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diff --git a/3311/CH10/EX10.1/Ex10_1.sce b/3311/CH10/EX10.1/Ex10_1.sce
new file mode 100755
index 000000000..de368d754
--- /dev/null
+++ b/3311/CH10/EX10.1/Ex10_1.sce
@@ -0,0 +1,25 @@
+// chapter 10
+// example 10.1
+// Determine required supply voltage, thyristor rating and power factor of the supply current
+// page-698-699
+clear;
+clc;
+// given
+m=3; // number of phases
+PF=0.7; // power factor (lagging)
+Edc=190; // in V (load voltage)
+I_L=45; // in A 
+// calculate
+// since Edc=(m/%pi)*Eph*sin(%pi/m), therefore we get
+Eph=Edc/((m/%pi)*sin(%pi/m)); // calculation of required supply voltage
+Eph_max=Eph*sqrt(2); // calculation of required supply voltage maximum value
+Imax=I_L*sqrt(2); // calculation of maximum value of cycloconvertor current
+Irms=Imax/sqrt(3); // calculation of thyristor rms current
+PIV=sqrt(3)*Eph_max; // calculation of peak inverse voltage
+Irms_1_3=sqrt(I_L^2/3); // calculation of rms current for one-third cycle
+Pin=(1/3)*Edc*I_L*PF; // calculation of input power per phase
+pf=Pin/(Eph*Irms_1_3); // calculation of power factor of the supply current
+printf("\nThe required supply voltage is \t\t\t Eph=%.2f V",Eph);
+printf("\nThe thyristor ratings are \t\t\t Irms==%.2f A \t PIV=%.2f V",Irms,PIV);
+printf("\nThe power factor of the supply current is \t pf=%.2f",pf);
+// Note: 1. The answers vary slightly due to precise calculation.
\ No newline at end of file
diff --git a/3311/CH10/EX10.2/Ex10_2.sce b/3311/CH10/EX10.2/Ex10_2.sce
new file mode 100755
index 000000000..0c806a74d
--- /dev/null
+++ b/3311/CH10/EX10.2/Ex10_2.sce
@@ -0,0 +1,27 @@
+// chapter 10
+// example 10.2
+// Estimate peak and rms value of load voltage
+// page-699-700
+clear;
+clc;
+// given
+E=600; // in V (line voltage)
+f=50; // in Hz (supply frequency)
+Ls=1.46; // in mH (inductance per phase)
+I_L=28; // in A (load current)
+p=6; // number of pulses
+alpha1=0,alpha2=30, alpha3=60; // in degrees (firing angles)
+// calculate
+Ls=Ls*1E-3; // changing unit from mH to H
+Em=E*sqrt(2); // calculation of peak value of supply voltage
+w=2*%pi*f; // calculation of angular frequency in radian
+// since Epeak=(p/%pi)*Em*sin(%pi/p)*cosd(alpha)-(p*w*Ls*I_L/(2*%pi)), therefore we get
+for alpha=0:30:60
+    Epeak=(p/%pi)*Em*sin(%pi/p)*cosd(alpha)-(p*w*Ls*I_L/(2*%pi)); // calculation of peak value of load voltage
+    Erms=Epeak/sqrt(2); // calculation of rms value of load voltage
+    printf("\n\nFor alpha=%.f degree,",alpha);
+    printf("\nThe peak value of load voltage is \t Epeak=%.1f V",Epeak);
+    printf("\nThe rms value of load voltage is  \t Erms=%.1f V",Erms);
+end
+// Note: 1. The value of E used in calculation in the book is 660 V while the value given is 600 V. So i have used 600 V for the calculationas given in the question statement. Therefore the answers do not match.
+//       2. The answers vary slightly due to precise calculation.
\ No newline at end of file
diff --git a/3311/CH10/EX10.3/Ex10_3.sce b/3311/CH10/EX10.3/Ex10_3.sce
new file mode 100755
index 000000000..c44add113
--- /dev/null
+++ b/3311/CH10/EX10.3/Ex10_3.sce
@@ -0,0 +1,25 @@
+// chapter 10
+// example 10.3
+// Determine the value of fundamental rms output voltage, rms output current and output power
+// page-700
+clear;
+clc;
+// given
+n=3/1; // transformer turn ratio
+wL=3; // in ohm (inductive reactance)
+R_L=4; // in ohm (load resistance)
+alpha=160; // in degree (firing angle)
+E=410; // in V (input voltage per phase)
+f=50; // in Hz (supply frequency)
+m=3; // number of phases
+// calculate
+Eph=E/2; // calculation of per phase voltage to convertor
+r=cosd(180-alpha); // calculation of voltage reduction factor
+Eor=r*Eph*(m/%pi)*sin(%pi/m); // calculation of fundamental rms output voltage,
+Ior_magnitude=Eor/sqrt(R_L^2+wL^2); // calculation of rms output current magnitude
+Ior_phase=-atand(wL/R_L); // calculation of rms output current phase
+P0=Ior_magnitude^2*R_L; // calculation of output power
+printf("\nThe fundamental rms output voltage is \t Eor=%.2f V",Eor);
+printf("\nThe rms output current is  \t Ior=%.2f A \t and phase is \t %.2f degree",Ior_magnitude,Ior_phase);
+printf("\nThe output power is \t P0=%.2f W",P0);
+// Note: The answers vary slightly due to precise calculation.
\ No newline at end of file
diff --git a/3311/CH10/EX10.4/Ex10_4.sce b/3311/CH10/EX10.4/Ex10_4.sce
new file mode 100755
index 000000000..f4c46d40f
--- /dev/null
+++ b/3311/CH10/EX10.4/Ex10_4.sce
@@ -0,0 +1,26 @@
+// chapter 10
+// example 10.4
+// Determine the value of fundamental rms output voltage, rms output current and output power
+// page-700-701
+clear;
+clc;
+// given
+n=3/1; // transformer turn ratio
+wL=3; // in ohm (inductive reactance)
+R_L=4; // in ohm (load resistance)
+alpha=160; // in degree (firing angle)
+E=410; // in V (input voltage per phase)
+f=50; // in Hz (supply frequency)
+m=6; // number of pulses
+// calculate
+Eph=E/2; // calculation of per phase voltage to convertor
+E_line=Eph*sqrt(3); // calculation of input to bridge invertor
+r=cosd(180-alpha); // calculation of voltage reduction factor
+Eor=r*E_line*(m/%pi)*sin(%pi/m); // calculation of fundamental rms output voltage,
+Ior_magnitude=Eor/sqrt(R_L^2+wL^2); // calculation of rms output current magnitude
+Ior_phase=-atand(wL/R_L); // calculation of rms output current phase
+P0=Ior_magnitude^2*R_L; // calculation of output power
+printf("\nThe fundamental rms output voltage is \t Eor=%.2f V",Eor);
+printf("\nThe rms output current is  \t Ior=%.2f A \t and phase is \t %.2f degree",Ior_magnitude,Ior_phase);
+printf("\nThe output power is \t P0=%.2f W",P0);
+// Note: The answers vary slightly due to precise calculation.
\ No newline at end of file
diff --git a/3311/CH10/EX10.5/Ex10_5.sce b/3311/CH10/EX10.5/Ex10_5.sce
new file mode 100755
index 000000000..c623747cf
--- /dev/null
+++ b/3311/CH10/EX10.5/Ex10_5.sce
@@ -0,0 +1,17 @@
+// chapter 10
+// example 10.5
+// Determine the input current to the convertors
+// page-701
+clear;
+clc;
+// given
+m=6; // number of pulses
+Pi=50; // in kVA ()power of cycloconvertor)
+E=415; // in V
+theta=45; // in degree (firing angle)
+alpha0=0.8; // power factor
+// calculate
+Pi=Pi*1E3; // changing unit from kVA to VA
+// since Pi=3*E*Im_phase=3*E*I*(cos(theta)/sqrt(2))*alpha0, therefore we get
+I=Pi/(3*E*(cosd(theta)/sqrt(2))*alpha0);// calculation of input current to the convertors
+printf("\nThe input current to the convertors is \t I=%.2f A",I);
\ No newline at end of file
diff --git a/3311/CH11/EX11.1/Ex11_1.sce b/3311/CH11/EX11.1/Ex11_1.sce
new file mode 100755
index 000000000..b10f4505e
--- /dev/null
+++ b/3311/CH11/EX11.1/Ex11_1.sce
@@ -0,0 +1,33 @@
+// chapter 11
+// example 11.1
+// Determine the peak values of average and rms thyristor currents, minimum circuit turn-off time, the ratio of third harmonic voltage to fundamental voltage , maximum value of di/dt and the angle at which greatest forward or reverse voltage is applied.
+// page-718-719
+clear;
+clc;
+// given
+R=4; // in ohm
+E=230; // in V (supply voltage)
+f=50; // in Hz
+alpha=%pi/3; // in degree
+n=3
+// calculate
+Em=E*sqrt(2);// calculation of peak input voltage
+I_T_av_m=Em/(%pi*R);// calculation of peak value of average thyristor current
+I_T_rms_m=Em/(2*R);// calculation of peak value rms thyristor current
+w=2*%pi*f;// calculation of angluar frequency
+Toff=%pi/w;// calculation of minimum circuit turn-off time
+A3=(Em/%pi)*(sin((n+1)*alpha)/(n+1)-sin((n-1)*alpha)/(n-1));
+B3=(Em/%pi)*((cos((n+1)*alpha)-1)/(n+1)-(cos((n-1)*alpha)-1)/(n-1));
+E_3m=sqrt(A3^2+B3^2);
+E_1m=(Em/%pi)*sqrt((sin((n-1)*alpha)/2+(%pi-alpha))^2+((cos((n-1)*alpha)-1)/(n-1))^2);// calculation of 
+ratio=E_3m/E_1m;// calculation of the ratio of third harmonic voltage to fundamental voltage
+di_dt=%inf// calculation of maximum value of di/dt
+alpha2=%pi/2;// calculation of the angle at which greatest forward or reverse voltage is applied.
+Em_max=sqrt(2)*E;// calculation of magnitude of maximum voltage
+printf("\nThe peak value of average thyristor current is \t\t\t\t I_T_av_m=%.2f A",I_T_av_m);
+printf("\nThe peak value rms thyristor current is \t\t\t\t I_T_rms_m=%.2f A",I_T_rms_m);
+printf("\nThe minimum circuit turn-off time is \t\t\t\t\t Toff_m=%.f ms",Toff*1E3);
+printf("\nThe ratio of third harmonic voltage to fundamental voltage is \t\t %.3f ",ratio);
+printf("\nThe maximum value of di/dt is \t\t\t\t\t\t di/dt=%f A/s",di_dt);
+printf("\nThe angle at which greatest forward or reverse voltage is applied is \t alpha=%.2f radian",alpha2);
+printf("\nThe magnitude of maximum voltage is \t\t\t\t\t Em_max=%.2f V",Em_max);
\ No newline at end of file
diff --git a/3311/CH11/EX11.2/Ex11_2.sce b/3311/CH11/EX11.2/Ex11_2.sce
new file mode 100755
index 000000000..d7ba73c56
--- /dev/null
+++ b/3311/CH11/EX11.2/Ex11_2.sce
@@ -0,0 +1,29 @@
+// chapter 11
+// example 11.2
+// fig. Ex.  11.2
+// Determine rms value of output voltage, input power factor and average input current
+// page-719-721
+clear;
+clc;
+// given
+R=6; // in ohm
+Es=230; // in V (supply voltage)
+f=50; // in Hz
+alpha=%pi/2; // in degree
+n=3
+// calculate
+E0_rms=sqrt((2*Es^2/(4*%pi))*(integrate('1-cos(2*wt)','wt',alpha,%pi)+integrate('1-cos(2*wt)','wt',%pi,(2*%pi))));// calculation of rms value of output voltage
+I0_rms=E0_rms/R;// calculation of rms value of output current
+P0=I0_rms^2*R;// calculation of load power
+Ea=Es*I0_rms;// calculation of input voltage-ampere rating
+pf=P0/Ea;// calculation of input power factor
+Edc=(1/(2*%pi))*(sqrt(2)*Es*integrate('sin(wt)','wt',alpha,%pi)+sqrt(2)*Es*integrate('sin(wt)','wt',%pi,(2*%pi)));// calculation of average output voltage
+Idc=Edc/R;// calculation of average input current
+printf("\nThe rms value of output voltage is \t E0_rms=%.2f V",E0_rms);
+printf("\nThe input power factor is \t\t pf=%.3f ",pf);
+if pf>0 then
+    printf(" (lagging)");
+else
+    printf(" (leading)");
+end
+printf("\nThe average input current is \t\t Idc=%.2f A",Idc);
diff --git a/3311/CH11/EX11.3/Ex11_3.sce b/3311/CH11/EX11.3/Ex11_3.sce
new file mode 100755
index 000000000..4835c8b91
--- /dev/null
+++ b/3311/CH11/EX11.3/Ex11_3.sce
@@ -0,0 +1,35 @@
+// chapter 11
+// example 11.3
+// Determine control range of firing angle, maximum value of rms load current, maximum power and power factor, maximum values of average and rms thyristor current, maximum possible of di/dt and the conduction angle for alpha=0 and alpha=120
+// page-721-722
+clear;
+clc;
+// given
+R=4; // in ohm
+Es=230; // in V (supply voltage)
+f=50; // in Hz
+wL=3; // in ohm (inductive reactance)
+alpha1=0, alpha2=120; // in degree
+// calculate
+w=2*%pi*f;// calculation of angular frequency
+Em=Es*sqrt(2);// calculation of peak value of input voltage
+alpha_min=atand(wL/R);// calculation of minimum firing angle
+alpha_max=180;// calculation of maximum firing angle
+Z=sqrt(R^2+wL^2);// calculation of impedence
+I0_rms_m=Es/Z;// calculation of maximum value of rms load current
+P0=I0_rms_m^2*R;// calculation of maximum power
+pf=P0/(Es*I0_rms_m);// calculation of power factor
+I_T_av=(Em/(%pi*Z));// calculation of maximum values of average thyristor current
+I_T_rms=Em/(2*Z);// calculation of maximum values of rms thyristor current
+di_dt=w*Em/Z;// calculation of maximum possible of di/dt
+gama1=180;// calculation of the conduction angle for alpha=0 
+gama2=95;// calculation of the conduction angle for alpha=120
+printf("\nThe control range of firing angle is \t %.2f degree  <=  alpha  <=  %.2f degree",alpha_min,alpha_max);
+printf("\nThe maximum value of rms load current is \t\t I0_rms_m=%.f A",I0_rms_m);
+printf("\nThe maximum power is \t\t\t\t\t P0=%.f W",P0);
+printf("\nThe power factor is \t\t\t\t\t pf=%.1f",pf);
+printf("\nThe maximum values of average thyristor current is \t I_T_av=%.3f A",I_T_av);
+printf("\nThe maximum values of rms thyristor current is \t\t I_T_rms=%.3f A",I_T_rms);
+printf("\nThe maximum possible of di/dt is \t\t\t di/dt=%1E A/s",di_dt);
+printf("\nThe conduction angle for alpha=0 is \t\t\t gama1=%.f degree",gama1);
+printf("\nThe conduction angle for alpha=120 is \t\t\t gama2=%.f degree",gama2);
diff --git a/3311/CH11/EX11.4/Ex11_4.sce b/3311/CH11/EX11.4/Ex11_4.sce
new file mode 100755
index 000000000..3677f6498
--- /dev/null
+++ b/3311/CH11/EX11.4/Ex11_4.sce
@@ -0,0 +1,29 @@
+// chapter 11
+// example 11.4
+// Plot a curve of load power against firing delay angle and determine required thyristor rating
+// page-722
+clear;
+clc;
+clf;
+// given
+R=10; // in ohm
+E1=100; // in V
+E2=70.7; // in V
+f=50; // in Hz (used by the author)
+// calculate
+w=2*%pi*f;
+alpha=[0:0.1:%pi];
+P0=1000-(500*alpha-250*sin(2*alpha))/%pi;
+plot2d(alpha,P0,nax=[2,3,2,3],rect=[0,0,%pi,1000]);
+PRV_12=E1*sqrt(2);
+PRV_34=E2*sqrt(2);
+printf("\nTHe peak reverse voltage for thyristor T1 and T2 is \t PRV=%.f V",PRV_12);
+printf("\nTHe peak reverse voltage for thyristor T3 and T3 is \t PRV=%.f V",PRV_34);
+I_T_max_12=E1*sqrt(2)/R;
+I_T_max_34=E2*sqrt(2)/R;
+I_T_rms_12=I_T_max_12/2;
+I_T_rms_34=I_T_max_34/2;
+printf("\nTHe maximum current for thyristor T1 and T2 is \t I_T_12=%.1f A",I_T_max_12);
+printf("\nTHe maximum current for thyristor T3 and T3 is \t I_T_34=%.1f A",I_T_max_34);
+printf("\nTHe rms current for thyristor T1 and T2 is \t I_T_12=%.1f A",I_T_rms_12);
+printf("\nTHe rms current for thyristor T3 and T3 is \t I_T_34=%.1f A",I_T_rms_34);
\ No newline at end of file
diff --git a/3311/CH11/EX11.5/Ex11_5.sce b/3311/CH11/EX11.5/Ex11_5.sce
new file mode 100755
index 000000000..be3f2e509
--- /dev/null
+++ b/3311/CH11/EX11.5/Ex11_5.sce
@@ -0,0 +1,30 @@
+// chapter 11
+// example 11.5
+// fig. 11.9
+// Determine rms current of tyristor T1 and T2, rms current of Thyristor T3 and T4 and input power factor
+// page-722-723
+clear;
+clc;
+// given
+e1=130; // in V
+e2=130; // in V
+Ep=260; // in V
+E0=195; // in V
+R=6; // in ohm 
+alpha=%pi/2; // in radian (firing angle)
+// calculate
+I1=sqrt((1/(2*%pi*R^2))*2*(e1+e2)^2*integrate('(sin(wt))^2','wt',alpha,%pi)); // calculation of rms current of tyristor T1 and T2
+I2=sqrt((1/(2*%pi*R^2))*2*(e1^2)*integrate('(sin (wt))^2','wt',0,alpha)); // calculation of rms current of Thyristor T3 and T4
+Iw2=sqrt(2)*I1; // calculation of rms current of second winding
+Iw1=sqrt((sqrt(2)*I1)^2+(sqrt(2)*I2)^2); // calculation of rms current of first winding
+Ea=e1*Iw1+e2*Iw2; // calculation of volt-ampere rating
+P0=E0^2/R; // calculation of maximum power
+PF=P0/Ea; // calculation of power factor
+printf("\nThe rms current of tyristor T1 and T2 is \t I1=%.2f A",I1);
+printf("\nThe rms current of Thyristor T3 and T4 is \t I2=%.2f A",I2);
+printf("\nThe power factor is \t\t\t pf=%.3f",PF);
+if PF>0 then
+    printf(" (lagging)");
+else
+    printf(" (laeding)");
+end
diff --git a/3311/CH11/EX11.6/Ex11_6.sce b/3311/CH11/EX11.6/Ex11_6.sce
new file mode 100755
index 000000000..4f6d63a5a
--- /dev/null
+++ b/3311/CH11/EX11.6/Ex11_6.sce
@@ -0,0 +1,26 @@
+// chapter 11
+// example 11.6
+// Determine rms output phase voltage, input power factor
+// page-741-742
+clear;
+clc;
+// given
+E_L=210; // in V
+R=5; // in ohm 
+alpha=%pi/3; // in radian (firing angle)
+// calculate
+Es=E_L/sqrt(3);
+E0=sqrt((2*Es^2/(4*%pi))*(integrate('1-cos(2*wt)','wt',alpha,%pi)+integrate('1-cos(2*wt)','wt',%pi,(2*%pi))));// calculation of rms output pahse voltage
+Ia=E0/R; // calculation of rms current
+P0=3*Ia^2*R; // calculation of maximum power
+I_L=Ia; // calculation of load current
+EA=3*Es*I_L; // calculation of volt-ampere rating
+pf=P0/EA; // calculation of power factor
+printf("\nThe rms output phase voltage is \t E0=%.3f V",E0);
+printf("\nThe power factor is \t\t\t pf=%.3f",pf);
+if pf>0 then
+    printf(" (lagging)");
+else
+    printf(" (laeding)");
+end
+// Note part-c of this question is a derivation type which i havenot done
\ No newline at end of file
diff --git a/3311/CH11/EX11.7/Ex11_7.sce b/3311/CH11/EX11.7/Ex11_7.sce
new file mode 100755
index 000000000..425ebb8be
--- /dev/null
+++ b/3311/CH11/EX11.7/Ex11_7.sce
@@ -0,0 +1,21 @@
+// chapter 11
+// example 11.7
+// Determine required ratings of triacs and thyrstors
+// page-742
+clear;
+clc;
+// given
+Es=415; // in V
+P0=15; // in kW
+// calculate
+P0=P0*1E3; // changing unit from kW to W
+E_line=Es*sqrt(3); // calculation of line voltage
+I_line_rms=P0/E_line; // calculation of rms line current for traics
+V_offstate=Es*sqrt(2); // calculation of peak offstate voltage for traics
+I_rms=I_line_rms/sqrt(2); // calculation of required rms current rating for thyristor
+printf("\n For Traics");
+printf("\n\t\tThe rms line current is \t I_line_rms=%.1f A",I_line_rms);
+printf("\n\t\tThe peak offstate voltage is \t V_offstate=%.f V",V_offstate);
+printf("\n\n For thyristors");
+printf("\n\t\tThe required rms current rating is \t\t I_rms=%.1f A",I_rms);
+printf("\n\t\tThe voltage requirement will be same as that of triacs  %.f V",V_offstate);
diff --git a/3311/CH12/EX12.1/Ex12_1.sce b/3311/CH12/EX12.1/Ex12_1.sce
new file mode 100755
index 000000000..bfb99f22f
--- /dev/null
+++ b/3311/CH12/EX12.1/Ex12_1.sce
@@ -0,0 +1,38 @@
+// chapter 12
+// example 12.1
+// Determine circuit turn-off time, maximum possible output frequency, capacitor voltage, rms load current, output power and average and rms SCR currents
+// page-755-756
+clear;
+clc;
+// given
+Edc=200; // in V (dc input)
+Lr=40; // in uH (resonant inductor)
+Cr=6.8; // in uF (resonant capacitor)
+F=6; // in Khz (frequency of output voltage)
+t_q=15; // in us (SCR turn-off time)
+R=3; // in ohm
+// calculate
+Lr=Lr*1E-6; // changing unit from uH to H
+Cr=Cr*1E-6; // changing unit from uF to F
+t_q=t_q*1E-6; // changing unit from us to s
+F=F*1E3; // changing unit from KHz to Hz
+wr=sqrt((1/(Lr*Cr))-R^2/(4*Lr^2));
+// since wr=2*%pi*fr, therefore we get,
+fr=wr/(2*%pi);
+w0=2*%pi*F;
+Toff=(%pi/w0)-(%pi/wr); // calculation of circuit turn-off time
+Fmax=1/(2*(t_q+(%pi/wr))); // calculation of maximum possible output frequency
+Ec=Edc*((exp(R*%pi/(2*Lr*wr))+1)/(exp(R*%pi/(2*Lr*wr))-1)); // calculation of capacitor voltage
+I_L_rms=((Edc+Ec)/(wr*Lr))*sqrt(F*(1-exp(-R*%pi/(2*wr*Lr)))*((Lr/R)-(R/Lr)*(1/((2*wr)^2+(R/Lr)^2)))); // calculation of rms load current
+P0=I_L_rms^2*R; // calculation of output power
+I_rms_SCR=I_L_rms/sqrt(2); // calculation of rms SCR current
+I_L_avg=(2*F*(Edc+Ec)/((wr^2+(R/(2*Lr)^2))*Lr))*1+exp(-R*%pi/(4*wr*Lr)); // calculation of average load current
+I_avg_SCR=I_L_avg/2; // calculation of average SCR current
+printf("\nThe circuit turn-off time is \t\t\t Toff=%.1f us",Toff*1E6);
+printf("\nThe maximum possible output frequency is \t Fmax=%.3f KHz",Fmax*1E-3);
+printf("\nThe capacitor voltage is \t\t\t Ec=%.2f V",Ec);
+printf("\nThe rms load current is \t\t\t I_L_rms=%.2f A",I_L_rms);
+printf("\nThe output power is \t\t\t\t P0=%.2f W",P0);
+printf("\nThe rms SCR current is \t\t\t\t I_rms_SCR=%.2f A",I_rms_SCR);
+printf("\nThe average SCR current is \t\t\t I_avg_SCR=%.3f A",I_avg_SCR);
+// Note : The answers vary slightly due to precise calculation
diff --git a/3311/CH12/EX12.2/Ex12_2.sce b/3311/CH12/EX12.2/Ex12_2.sce
new file mode 100755
index 000000000..bd7a36d5d
--- /dev/null
+++ b/3311/CH12/EX12.2/Ex12_2.sce
@@ -0,0 +1,42 @@
+// chapter 12
+// example 12.2
+// fig. 12.8
+// Determine resonant frequency, maximum operating frequency,Peak thyristor current, average thyristor current, rms thyristor current, rms load current and average supply current
+// page-760-762
+clear;
+clc;
+// given
+C1=4; // in uF
+C2=4; // in uF
+Lr=40; // in uH
+R=2; // in ohm
+Edc=120; // in V (input voltage)
+t_q=20; // in us (SCR turn-off time)
+// calculate
+Lr=Lr*1E-6; // changing unit from uH to H
+t_q=t_q*1E-6; // changing unit from us to s
+Ceq=C1+C2;
+Ceq=Ceq*1E-6; // changing unit from uF to F
+wr=sqrt((1/(Lr*Ceq))-R^2/(4*Lr^2)); // calculation of resonant angular frequency
+fr=wr/(2*%pi); // calculation of resonant frequency
+tr=1/fr; // calculation of resonant time-period
+fr_max=1/(2*t_q); // calculation of maximum frequency
+f0=0.4*fr; // calculation of output frequency
+T0=1/f0; // calculation of output period
+td=T0/2-tr; // calculation of delay time
+tp=(1/wr)*atan(2*wr*Lr/R); // calculation of time at which peak current is obtained
+Ec1=Edc/(exp(R*2*%pi/(2*Lr*wr))+1); // calculation of  initial capacitor voltage
+Ip=(Edc+Ec1)/(wr*Lr)*sin(wr*tp)*exp(-R*tp/(2*Lr)); // calculation of peak current
+I_av_SCR=(Edc+Ec1)/(wr*Lr)*(1/T0)*integrate('sin(wr*t)*exp(-R*t/(2*Lr))','t',0,tr/2); // calculation of average thyristor current
+I_rms_SCR=(Edc+Ec1)/(wr*Lr)*sqrt((1/T0)*(integrate('(sin(wr*t))^2*exp(-R*t/Lr)','t',0,tr/2))); // calculation of rms thyristor current
+I0=2*I_rms_SCR; // calculation of rms load current
+P0=I0^2*R; // calculation of output power
+Is=P0/Edc; // calculation of average supply current
+printf("\nThe resonant frequency is \t\t\t fr=%.3f KHz",fr*1E-3);
+printf("\nThe maximum possible operating frequency is \t fr_max=%.f KHz",fr_max*1E-3);
+printf("\nThe Peak thyristor current is \t\t\t Ip=%.2f A",Ip);
+printf("\nThe average thyristor current is \t\t I_av_SCR=%.3f A",I_av_SCR);
+printf("\nThe rms thyristor current is \t\t\t I_rms_SCR=%.2f A",I_rms_SCR);
+printf("\nThe rms load current is \t\t\t I0=%.1f A",I0);
+printf("\nThe average supply current is \t\t\t Is=%.2f A",Is);
+// Note : The answers vary slightly due to precise calculation
diff --git a/3311/CH12/EX12.3/Ex12_3.sce b/3311/CH12/EX12.3/Ex12_3.sce
new file mode 100755
index 000000000..eac32191b
--- /dev/null
+++ b/3311/CH12/EX12.3/Ex12_3.sce
@@ -0,0 +1,42 @@
+// chapter 12
+// example 12.3
+// Determine resonant frequency, maximum operating frequency,Peak thyristor current, average thyristor current, rms thyristor current, rms load current and average supply current
+// page-765-767
+clear;
+clc;
+// given
+Cr=8; // in uF
+Lr=40; // in uH
+R=2; // in ohm
+Edc=120; // in V (input voltage)
+t_q=20; // in us (SCR turn-off time)
+// calculate
+Lr=Lr*1E-6; // changing unit from uH to H
+t_q=t_q*1E-6; // changing unit from us to s
+Cr=Cr*1E-6; // changing unit from uF to F
+wr=sqrt((1/(Lr*Cr))-R^2/(4*Lr^2)); // calculation of resonant angular frequency
+fr=wr/(2*%pi); // calculation of resonant frequency
+f0=0.4*fr; // calculation of output frequency
+tr=1/fr; // calculation of resonant time-period
+T0=1/f0; // calculation of output period
+td=T0/2-tr; // calculation of delay time
+fr_max=1/(2*t_q); // calculation of maximum frequency
+f0_max=fr_max/2; // calculation of maximum foutput frequency
+tp=(1/wr)*atan(2*wr*Lr/R); // calculation of time at which peak current is obtained
+Ec1=Edc*((1-exp(-R*%pi/(Lr*wr)))/(1+exp(-R*%pi/(Lr*wr)))); // calculation of  initial capacitor voltage
+Ip=(Edc+Ec1)/(wr*Lr)*sin(wr*tp)*exp(-R*tp/(2*Lr)); // calculation of peak current
+I_avg_SCR=(Edc+Ec1)/(wr*Lr)*(1/T0)*integrate('sin(wr*t)*exp(-R*t/(2*Lr))','t',0,tr/2); // calculation of average thyristor current
+I_rms_SCR=(Edc+Ec1)/(wr*Lr)*sqrt((1/T0)*(integrate('(sin(wr*t))^2*exp(-R*t/Lr)','t',0,tr/2))); // calculation of rms thyristor current
+I0=2*I_rms_SCR; // calculation of rms load current
+P0=I0^2*R; // calculation of output power
+Is=P0/Edc; // calculation of average supply current
+printf("\nThe resonant frequency is \t\t\t fr=%.2f KHz",fr*1E-3);
+printf("\nThe maximum possible operating frequency is \t fr_max=%.f KHz",fr_max*1E-3);
+printf("\nThe maximum possible output frequency is \t f0_max=%.1f KHz",f0_max*1E-3);
+printf("\nThe Peak thyristor current is \t\t\t Ip=%.3f A",Ip);
+printf("\nThe average thyristor current is \t\t I_avg_SCR=%.3f A",I_avg_SCR);
+printf("\nThe rms thyristor current is \t\t\t I_rms_SCR=%.2f A",I_rms_SCR);
+printf("\nThe rms load current is \t\t\t I0=%.1f A",I0);
+printf("\nThe average supply current is \t\t\t Is=%.2f A",Is);
+// Note : 1. The answer for I_avg_SCR, I_rms_SCR, I0, P0 and Is are wrong in the book due to the use of wrong value of Ec1 in the calculation
+//        2.The answers vary slightly due to precise calculation
diff --git a/3311/CH12/EX12.4/Ex12_4.sce b/3311/CH12/EX12.4/Ex12_4.sce
new file mode 100755
index 000000000..2f28c7ddf
--- /dev/null
+++ b/3311/CH12/EX12.4/Ex12_4.sce
@@ -0,0 +1,28 @@
+// chapter 12
+// example 12.4
+// Design E-class resonant invertor
+// page-769-770
+clear;
+clc;
+// given
+R=12; // in ohm
+Edc=24; // in V (DC voltage)
+fs=20; // in KHz (switching frequency)
+Q=7; // assumption for quality factor as done in the book
+// calculate
+fs=fs*1E3; // changing unit from KHz to Hz
+ws=2*%pi*fs; // calculation of switching angular frequency
+Ldc=0.4*R/ws; // calculation of source inductance
+C1=2.165/(R*ws); // calculation of resonance element
+// since Q=ws*Lr/R, therefore we get,
+Lr=Q*R/ws; // calculation of inductance from series resonance
+// since ws*Lr-1/(ws*Cr)=0.353*R, therefore we get,
+Cr=(1/(ws*Lr-0.353*R))/ws; // calculation of capacitance from series resonance
+e=(R/2)*sqrt(Cr/Lr); // calculation of damping factor
+f0=1/(2*%pi*sqrt(Lr*Cr)); // calculation of resonance frequency
+printf("\nThe source inductance is \t\t\t Ldc=%.1f uH",Ldc*1E6);
+printf("\nThe resonance element is \t\t\t C1=%.1f uF",C1*1E6);
+printf("\nThe inductance from series resonance is \t Lr=%.1f uH",Lr*1E6);
+printf("\nThe capacitance from series resonance is \t Cr=%.2f uF",Cr*1E6);
+printf("\nThe resonance frequency is \t\t\t f0=%.2f KHz",f0*1E-3);
+// Note :The answers vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH12/EX12.5/Ex12_5.sce b/3311/CH12/EX12.5/Ex12_5.sce
new file mode 100755
index 000000000..8bc32b22a
--- /dev/null
+++ b/3311/CH12/EX12.5/Ex12_5.sce
@@ -0,0 +1,27 @@
+// chapter 12
+// example 12.5
+// Destermine values of resonant components Lr and Cr, peak switching current, peak voltage rating of the resonant capacitor
+// page-778-780
+clear;
+clc;
+// given
+Edc=18; // in V (unregulated DC voltage)
+E0=12; // in V (output voltage)
+fr=1; // in MHz
+P0=12; // in W
+// calculate
+fr=fr*1E6; // changing unit from MHz to Hz
+// since P0=E0*I0, therefore we get,
+I0=P0/E0; // calculation of load current
+Zr=Edc/I0; // calculation of load impedance
+// since Zr=sqrt(Lr/Cr) and fr=1/(2*%pi*sqrt(Lr*Cr)), multiplying two equations, we get
+// Zr*fr=1/(2*%pi*Cr), therefore
+Cr=1/(2*%pi*Zr*fr); // calculation of resonant capacitance
+Lr=Zr^2*Cr; // calculation of resonant inductance
+is_p=I0+Edc*sqrt(Cr/Lr); // calculation of peak switch current
+Vc_peak=2*Edc; // calculation of peak voltage rating of capacitor
+printf("\nThe resonant capacitance is \t\t\t Cr=%.5f uF",Cr*1E6);
+printf("\nThe resonant inductance is \t\t\t Lr=%.2f uH",Lr*1E6);
+printf("\nThe peak switch current is \t\t\t is_p=%.2f A",is_p);
+printf("\nThe peak voltage rating of capacitor is \t Vc_peak=%.f V",Vc_peak);
+// Note :The answer in the book are wrong due to calculation mistake while calculating Cr and hence all other answer are also wrong
diff --git a/3311/CH12/EX12.6/Ex12_6.sce b/3311/CH12/EX12.6/Ex12_6.sce
new file mode 100755
index 000000000..0b39132fc
--- /dev/null
+++ b/3311/CH12/EX12.6/Ex12_6.sce
@@ -0,0 +1,29 @@
+// chapter 12
+// example 12.6
+// Determine values of resonant components Lr and Cr, peak voltage rating of the resonant capacitor and charging and discharging period of capcaitor
+// page-785-786
+clear;
+clc;
+// given
+Edc=35; // in V
+E0=24; // in V (output voltage)
+fr=500; // in KHz
+P0=24; // in W
+// calculate
+fr=fr*1E3; // changing unit from KHz to Hz
+// since P0=E0*I0, therefore we get,
+I0=P0/E0; // calculation of load current
+Zr=Edc/I0; // calculation of load impedance
+// since Zr=sqrt(Lr/Cr) and fr=1/(2*%pi*sqrt(Lr*Cr)), multiplying two equations, we get
+// Zr*fr=1/(2*%pi*Cr), therefore
+Cr=1/(2*%pi*Zr*fr); // calculation of resonant capacitance
+Lr=Zr^2*Cr; // calculation of resonant inductance
+Vs_p=Edc+I0*Zr; // calculation of peak voltage rating of capacitor
+t1=Edc*Cr/I0; // calculation of charging period of capcaitor
+t3=sqrt(Lr*Cr)*asin(Edc*sqrt(Cr/Lr)/I0); // calculation of  discharging period of capcaitor
+printf("\nThe resonant capacitance is \t\t\t Cr=%.4f uF",Cr*1E6);
+printf("\nThe resonant inductance is \t\t\t Lr=%.2f uH",Lr*1E6);
+printf("\nThe peak voltage rating of capacitor is \t Vs_p=%.f V",Vs_p);
+printf("\nThe charging period of capcaitor is \t\t t1=%.3f us",t1*1E6);
+printf("\nThe discharging period of capcaitor is \t\t t3=%.3f us",t3*1E6);
+// Note :The answer vary slightly due to precise calculation
diff --git a/3311/CH12/EX12.7/Ex12_7.sce b/3311/CH12/EX12.7/Ex12_7.sce
new file mode 100755
index 000000000..be9db4e63
--- /dev/null
+++ b/3311/CH12/EX12.7/Ex12_7.sce
@@ -0,0 +1,43 @@
+// chapter 12
+// example 12.7
+// Design a ZVS three-level PWM convertor
+// page-791-792
+clear;
+clc;
+// given
+Edc=300; // in V
+E0=60; // in V (output voltage)
+I0=10; // in A
+fs=120; // in KHz
+Deff=0.5; // effective duty ratio
+del_D=25; // assumption for reduction in duty ratio in percentage of duty ratio as done in the book
+TLI=3.46; // in uH (assuming transformer leakage inductance as done in the book)
+C=500; // in pF (assuming intrinsic capacitance of MOSFET as done in the book)
+// calculate
+fs=fs*1E3; // changing unit from KHz to Hz
+TLI=TLI*1E-6; // changing unit from uH to H
+C=C*1E-12; // changing unit from pF to F
+// since Deff=2*n*E0/Edc,  therefore we get,
+n=Deff*Edc/(2*E0); // calculation of transformer turns ratio
+// since Deff=D-del_D*D, therefore we get,
+D=Deff/(1-del_D/100); // calculation of duty ratio
+Lr=((del_D*D/100)*Edc/2)/(4*(I0/n)*fs); // calculation of resonant inductance
+Lr_eff=Lr+TLI; // calculation of effecive inductance
+I0_min=(n*Edc/2)*sqrt(1.5*C/Lr_eff); // calculation of minimum load current
+I_Lr=I0/n; // calculation of inductor current
+X_Lr=2*%pi*fs*Lr_eff; // calculation of inductive reactance
+V_Lr=I_Lr*X_Lr; // calculation of voltage drop across Lr
+// since E0=Deff*Es, therefore we get
+Es=E0/Deff; // calculation of secondary voltage
+Ep=n*Es; // calculation of primary voltage
+VA=Ep*I_Lr; // calculation of transformer volt-ampere
+printf("\nThe duty ratio is \t\t D=%.2f",D);
+printf("\nThe resonant inductance is \t Lr=%.2f uH",Lr*1E6);
+printf("\nThe effective inductance is \t Lr_eff=%.f uH",Lr_eff*1E6);
+printf("\nThe minimum load current is \t I0_min=%.2f A",I0_min);
+printf("\nThe inductor current is \t I_Lr=%.f A",I_Lr);
+printf("\nThe voltage drop across Lr is \t V_Lr=%.2f V",V_Lr);
+printf("\nThe secondary voltage is \t Es=%.f V",Es);
+printf("\nThe primary voltage is \t\t Ep=%.f V",Ep);
+printf("\nThe transformer volt-ampere is \t VA=%.f VA",VA);
+// Note :The answer vary slightly due to precise calculation
diff --git a/3311/CH13/EX13.1/Ex13_1.sce b/3311/CH13/EX13.1/Ex13_1.sce
new file mode 100755
index 000000000..94bea3033
--- /dev/null
+++ b/3311/CH13/EX13.1/Ex13_1.sce
@@ -0,0 +1,22 @@
+// chapter 13
+// example 13.1
+// fig. 13.11
+// Compute the values of di/dt inductor and the snubber circuit component Rs and Cs
+// page-807-808
+clear;
+clc;
+// given
+E=400; // in V
+di_dt=50; // in A/us
+dv_dt=200; // in V/us
+// calculate
+// since di/dt=E/L, therefore we get
+L=E/di_dt; // calculation of 
+// since dV/dt=Rs*di/dt, therefore we get
+Rs=dv_dt/di_dt; // calculation of 
+Rs=10; // assuming the desired values
+Cs=0.1; // in uF assuming the desired value
+L=E*Rs/(dv_dt);
+printf("\nThe value of di/dt inductor is \t\t L=%.f uH",L);
+printf("\nThe snubber circuit component are \t Rs=%.f ohm \t Cs=%.1f uF",Rs,Cs);
+
diff --git a/3311/CH13/EX13.10/Ex13_10.sce b/3311/CH13/EX13.10/Ex13_10.sce
new file mode 100755
index 000000000..bc1c8a492
--- /dev/null
+++ b/3311/CH13/EX13.10/Ex13_10.sce
@@ -0,0 +1,18 @@
+// chapter 13

+// example 13.10

+// What is the minimum value of load inductance and what will be the new value of L

+// page-827

+clear;

+clc;

+// given

+di_dt=15; // in A/us

+Edc=150; //  in V

+R=620; // in ohm

+R_L=62; // in ohm

+// calculate

+di_dt=di_dt/1E-6; // changing unit from A/us to A/s

+L=Edc/di_dt; // calculation of minimum value of load inductance

+L1=Edc*((R+R_L)/R)/di_dt; // calculation of new value of L

+printf("\nThe minimum value of load inductance that will protect the device is \t L=%.f uH",L*1E6);

+printf("\nThe required new value of inductance \t\t\t\t\t L=%.f uH",L1*1E6);

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.11/Ex13_11.sce b/3311/CH13/EX13.11/Ex13_11.sce
new file mode 100755
index 000000000..6eab5485f
--- /dev/null
+++ b/3311/CH13/EX13.11/Ex13_11.sce
@@ -0,0 +1,16 @@
+// chapter 13

+// example 13.11

+// Compute the values of RF filter components

+// page-833

+clear;

+clc;

+// given

+R_L=120; // in ohm

+f0=50; // in KHz

+// calculate

+f0=f0*1E3; // changing unit from KHz to Hz

+L=R_L/(2*%pi*f0); // calculation of inductance

+C=1/(2*%pi*R_L*f0); // calculation of capacitance

+printf("\nThe inductance is \t L=%.2f uH",L*1E6);

+printf("\nThe capacitance is \t C=%.3f uF",C*1E6);

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.12/Ex13_12.sce b/3311/CH13/EX13.12/Ex13_12.sce
new file mode 100755
index 000000000..7da0db313
--- /dev/null
+++ b/3311/CH13/EX13.12/Ex13_12.sce
@@ -0,0 +1,19 @@
+// chapter 13

+// example 13.12

+// Determine the value of thermal resistance, heat sink and temperature at base

+// page-840

+clear;

+clc;

+// given

+Pa=30; // in W (power loss)

+Tc=125; // in degree C (junction temperature)

+Ta=40; // in degree C (ambient temperature)

+theta_CJ=0.7; // in degree C/W (junction to heat-sink thermal resistance)

+// calculate

+theta_CA=(Tc-Ta)/Pa; // calculation of total thermal resistance

+theta_CS=theta_CA-theta_CJ; // calculation of thermal resistance of heat sink

+T_base=Ta+(Pa*theta_CS); // calculation of temperature at base

+printf("\nThe  total thermal resistance is \t\t theta_CA=%.2f degree C/W",theta_CA);

+printf("\nThe  thermal resistance of heat sink is \t theta_CS=%.2f degree C/W",theta_CS);

+printf("\nThe temperature at base is \t\t\t T_base=%.f degree C",T_base);

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.13/Ex13_13.sce b/3311/CH13/EX13.13/Ex13_13.sce
new file mode 100755
index 000000000..8828881ea
--- /dev/null
+++ b/3311/CH13/EX13.13/Ex13_13.sce
@@ -0,0 +1,18 @@
+// chapter 13

+// example 13.13

+// Determine junction temperature

+// page-840

+clear;

+clc;

+// given

+E=440; // in V

+I0=960; // in A 

+Ta=80; // in ambient temperature

+Pa=150; // in W (on state power loss)

+Q_JC=0.15; // in degree C/W

+Q_CS=0.075; // in degree C/W

+Q_SA=0.45; // in degree C/W

+// calculate

+T_J=Ta+Pa*(Q_JC+Q_CS+Q_SA); // calculation of junction temperature

+printf("\nThe junction temperature is \t T_J=%.2f degree C",T_J);

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.14/Ex13_14.sce b/3311/CH13/EX13.14/Ex13_14.sce
new file mode 100755
index 000000000..51538e907
--- /dev/null
+++ b/3311/CH13/EX13.14/Ex13_14.sce
@@ -0,0 +1,20 @@
+// chapter 13

+// example 13.14

+// Determine total average power loss and percentage increase in deivce rating

+// page-840-841

+clear;

+clc;

+// given

+T_J=150; // in degree C (maximum junction temperature)

+Q_JC=0.015; // in degree C/W

+Q_CS=0.08; // in degree C/W

+Ta_1=60; // in degree (heat sink temperature1)

+Ta_2=50 // in degree (heat sink temperature2)

+// calculate

+Pav1=(T_J-Ta_1)/(Q_JC+Q_CS);

+Pav2=(T_J-Ta_2)/(Q_JC+Q_CS);

+percent_increase=((sqrt(Pav2)-sqrt(Pav1))/sqrt(Pav1))*100;

+printf("\nThe total average power loss is \t\t\t Pav1=%.2f W",Pav1);

+printf("\nThe required percentage increase in deivce rating is \t %.2f %%",percent_increase);

+

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.15/Ex13_15.sce b/3311/CH13/EX13.15/Ex13_15.sce
new file mode 100755
index 000000000..5e37948e6
--- /dev/null
+++ b/3311/CH13/EX13.15/Ex13_15.sce
@@ -0,0 +1,34 @@
+// chapter 13
+// example 13.15
+// fig. 13.40
+// Plot instantaneous junction temperature
+// page-841-842
+clear;
+clc;
+clf;
+// given
+P2=0, P4=0, P6=0; // in W
+P1=1000, P3=1400, P5=700; // in W
+t1=1, t3=1, t5=1; // in ms
+theta1=0.035, theta3=0.035, theta5=0.035; // in degree C/W
+t2=0.5, t4=0.5, t6=0.5; // in ms
+theta2=0.025, theta4=0.025, theta6=0.025; // in degree C/W
+// calculate
+del_TJ1=theta1*P1;
+del_TJ1_5=del_TJ1-theta2*P1;
+del_TJ2_5=del_TJ1_5+theta3*P3;
+del_TJ3=del_TJ2_5-theta4*P3;
+del_TJ4=del_TJ3+theta5*P5;
+del_TJ4_5=del_TJ4-theta6*P5;
+printf("\n\ndel_TJ1=%.f degree C",del_TJ1);
+printf("\n\ndel_TJ1_5=%.f degree C",del_TJ1_5);
+printf("\n\ndel_TJ2_5=%.f degree C",del_TJ2_5);
+printf("\n\ndel_TJ3=%.f degree C",del_TJ3);
+printf("\n\ndel_TJ4=%.f degree C",del_TJ4);
+printf("\n\ndel_TJ4_5=%.f degree C",del_TJ4_5);
+del_TJ=[del_TJ1 del_TJ1_5 del_TJ2_5 del_TJ3 del_TJ4 del_TJ4_5];
+plot2d(del_TJ,nax=[1,6,1,7],rect=[0,0,5,60]);
+xlabel("t (ms)");
+ylabel("del_TJ  (degree C)");
+title("Junction temperature rise plot");
+// Note :There is calculation mistake in the book while calculating del_TJ_3 and hence all other values are also affected. Thats why answers in the book are wrong
\ No newline at end of file
diff --git a/3311/CH13/EX13.16/Ex13_16.sce b/3311/CH13/EX13.16/Ex13_16.sce
new file mode 100755
index 000000000..d95e83cea
--- /dev/null
+++ b/3311/CH13/EX13.16/Ex13_16.sce
@@ -0,0 +1,30 @@
+// chapter 13

+// example 13.16

+// Determine the heat-sink required

+// page-841-842

+clear;

+clc;

+// given

+Vcc=100; // in V

+V_CE_on=1; // in V 

+I_on=20; // in A

+t_on=1; // in us

+t_off=2; // in us

+fs=10; // in kHz

+del=0.9; // duty cycle

+T_A=35; // in degree C

+T_J_max=125; // in degree C

+theta_JC=0.7; // in degree C/W

+theta_CS=0.1; // in degree C/W

+// calculate

+t_on=t_on*1E-6; // changing unit from us to s

+t_off=t_off*1E-6; // changing unit from us to s

+fs=fs*1E3; // changing unit from kHz to Hz

+P_cond=V_CE_on*I_on*del; // calcultion of average power

+P_loss=Vcc*I_on*(t_on+t_off)*fs/2; // calcultion of switching power loss

+P_diss=P_cond+P_loss; // calcultion of total power loss

+// since P_diss=(T_J_max-T_A)/(theta_JC+theta_CS+theta_SA), therefore we get

+theta_SA=((T_J_max-T_A)/P_diss)-theta_JC-theta_CS; // calcultion of heat-sink required

+printf("\nThe required heat sink is \t theta_SA=%.1f degree C/W",theta_SA);

+

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.17/Ex13_17.sce b/3311/CH13/EX13.17/Ex13_17.sce
new file mode 100755
index 000000000..3bd988b71
--- /dev/null
+++ b/3311/CH13/EX13.17/Ex13_17.sce
@@ -0,0 +1,27 @@
+// chapter 13

+// example 13.17

+// Determine the thermal resistance of the heat sink

+// page-842-843

+clear;

+clc;

+// given

+I_D=20; // in A

+t_on=10; // in us

+del=0.1; // in % (duty cycle)

+T_A=40; // in degree C

+T_J_max=150; // in degree C

+theta_JC=1.5; // in degree C/W

+R_ds_on=5; // in ohm

+T_pr=0.03; // assumption as done in the book

+// calculate

+t_on=t_on*1E-6; // changing unit from us to s

+P_cond=I_D^2*R_ds_on;

+P_peak=P_cond;

+// since P_peak=(T_J_max-T_C)/(T_pr*theta_JC), therefore we get

+T_C=T_J_max-P_peak*T_pr*theta_JC; 

+P_diss=(del/100)*P_peak;

+// since P_diss=(T_C-T_A)/theta_CA, therefore we get

+theta_CA=(T_C-T_A)/P_diss;

+printf("\nThe thermal resistance of the heat sink is \t theta_CA=%.f degree C/W",theta_CA);

+

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.18/Ex13_18.sce b/3311/CH13/EX13.18/Ex13_18.sce
new file mode 100755
index 000000000..5ee0cdf00
--- /dev/null
+++ b/3311/CH13/EX13.18/Ex13_18.sce
@@ -0,0 +1,19 @@
+// chapter 13
+// example 13.18
+// Determine the maximum power disspation
+// page-843
+clear;
+clc;
+// given
+Cs=0.2; // in J/degree C (thermal capacity)
+theta=0.7; // in degree C/W (thermal resistance)
+T_J=40; // in degree C (junction temperature)
+t=0.1; // in s
+// calculate
+power_diss_per_degreeC=1/theta; // calculation of power dissipation per degree Celsius rise
+tou=Cs/power_diss_per_degreeC; //  calculation of thermal time constant
+// since T_J=T_J_max*(1-exp(-t/tou)), therefore we get
+T_J_max=T_J/(1-exp(-t/tou)); //  calculation of maximum junction temperature
+P_max_diss=T_J_max*power_diss_per_degreeC; //  calculation of maximum power disspation
+printf("\nThe maximum power disspation is \t P_max_diss=%.f W",P_max_diss);
+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.2/Ex13_2.sce b/3311/CH13/EX13.2/Ex13_2.sce
new file mode 100755
index 000000000..921e37ed5
--- /dev/null
+++ b/3311/CH13/EX13.2/Ex13_2.sce
@@ -0,0 +1,19 @@
+// chapter 13

+// example 13.2

+// Compute the required parameters snubber circuit

+// page-809

+clear;

+clc;

+// given

+Em=380; // in V

+dv_dt=50; // in V/us

+L=0.1; // in mH

+sigma=0.65; // assumption for damping factor as done in the book

+// calculate

+dv_dt=dv_dt/1E-6; // changing unit from V/us to V/s

+L=L*1E-3; // changing unit from mH to H

+C=(1/(2*L))*(0.564*Em/dv_dt)^2;

+R=2*sigma*sqrt(L/C);

+printf("\nThe capacitance is \t C=%.3f uF",C*1E6);

+printf("\nThe resistance is \t R=%.2f ohm",R);

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.3/Ex13_3.sce b/3311/CH13/EX13.3/Ex13_3.sce
new file mode 100755
index 000000000..172f24b22
--- /dev/null
+++ b/3311/CH13/EX13.3/Ex13_3.sce
@@ -0,0 +1,24 @@
+// chapter 13

+// example 13.3

+// Design a snubber circuit

+// page-809

+clc;

+clear;

+// given

+VA=5; // in kVA

+Es=120; // in V (secondary voltage)

+f=400; // in Hz (switching frequency)

+L=100; // in uH 

+Ep=200; // in V (peak transient voltage)

+sigma=0.75; // assumption for damping factor as done in the book

+// calculate

+VA=VA*1E3; // changing unit from kVA to VA

+L=L*1E-6; // changing unit from uH to H

+C=10*VA*60/(Es^2*f); // calculation of capacitance in uF

+Esp=Es*sqrt(2); // calculation of peak switching voltage ratio

+Ep_Esp=Ep/Esp; // calculation of peak transient voltage Vs peak switching voltage ratio

+R=2*sigma*sqrt(L/(C*1E-6)); // calculation resistance

+printf("\nThe capacitance is \t C=%.2f uF",C);

+printf("\nThe peak transient voltage Vs peak switching voltage ratio is \t %.2f",Ep_Esp);

+printf("\nThe resistance is \t R=%.1f ohm",R);

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.4/Ex13_4.sce b/3311/CH13/EX13.4/Ex13_4.sce
new file mode 100755
index 000000000..3014f283b
--- /dev/null
+++ b/3311/CH13/EX13.4/Ex13_4.sce
@@ -0,0 +1,24 @@
+// chapter 13

+// example 13.4

+// fig. 13.13

+// Compute initial capacitor voltage, magnetizing current and capacitor value to limit the transient capcaitor voltage to Ep=330 V

+// page-809-810

+clear;

+clc;

+// given

+Es=140; // in V

+f=50; // in Hz

+Lm=3; // in mH

+theta=180; // in degree

+Ep=330; // in V 

+// calculate

+Lm=Lm*1E-3; // changing unit from mH to H

+Em=sqrt(2)*Es; // calculation of peak voltage

+Vc_0=Em*sind(theta); // calculation of initial capacitor voltage

+w=2*%pi*f; // calculation of angular frequency

+Im=(-Em/(w*Lm))*cosd(theta); // calculation of magnetizing current 

+C=Im*Em/(Ep^2*w); // calculation of capacitor value to limit the transient capcaitor voltage

+printf("\nThe initial capacitor voltage is \t\t\t\t\t\t Vc_0= %.f V",abs(Vc_0));

+printf("\nThe magnetizing current is \t\t\t\t\t\t\t Im= %.f A",Im);

+printf("\nThe capacitor value to limit the transient capcaitor voltage to Ep=%.f V is \t C= %.1f uF",Ep,C*1E6);

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.5/Ex13_5.sce b/3311/CH13/EX13.5/Ex13_5.sce
new file mode 100755
index 000000000..a4ae1caf9
--- /dev/null
+++ b/3311/CH13/EX13.5/Ex13_5.sce
@@ -0,0 +1,29 @@
+// chapter 13

+// example 13.5

+// fig. 13.14

+// Determine the snubber component values for critical damping, value of R and power loss

+// page-810-811

+clear;

+clc;

+// given

+Edc=30; // in V

+fs=40; // in kHz

+i_L=30; // in A (load current)

+t_r=80; // in ns (rise time)

+t_f=30; // in ns (fall time)

+neta=10; // in % (ratio of maximum discharge current to load current)

+// calculate

+fs=fs*1E3; // changing unit from kHz to Hz

+t_r=t_r*1E-9; // changing unit from ns to s

+t_f=t_f*1E-9; // changing unit from ns to s

+L=Edc*t_r/i_L; // calculation of inductance

+C=i_L*t_f/Edc; // calculation of capacitance

+R=sqrt(4*L/C); // calculation of resistance for critical damping

+R1=Edc/((neta/100)*i_L); // calculation of resistance if maximum discharge current is limited to 10 % of load current

+Ploss=(1/2)*C*Edc^2*fs; // calculation of power loss

+printf("\nThe inductance is \t L=%.f nH",L*1E9);

+printf("\nThe capacitance is \t C=%.f nF",C*1E9);

+printf("\nThe resistance is \t R=%.2f ohm",R);

+printf("\nThe resistance if maximum discharge current is limited to 10 %% of load current is \t R=%.f ohm",R1);

+printf("\nThe power loss due to RC snubber circuit is \t Ploss=%.2f W",Ploss);

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.6/Ex13_6.sce b/3311/CH13/EX13.6/Ex13_6.sce
new file mode 100755
index 000000000..d72a72a3d
--- /dev/null
+++ b/3311/CH13/EX13.6/Ex13_6.sce
@@ -0,0 +1,25 @@
+// chapter 13

+// example 13.6

+// Design a suitable selenium voltage protection circuit and compute energy dissipated per plate

+// page-814

+clear;

+clc;

+// given

+Edc=440; // in V

+Imax=120; // in A

+R=0.175; // in ohm

+T=25; // in ms (time constant)

+V=40; // in V

+// calculate

+T=T*1E-3; // changing unit from ms to s

+n=Edc/V; // calculation of number of plates in each branch

+N=3*n; // calculation of total number of plates

+L=T*R; // calculation of armature circuit inductance

+E_stored=(1/2)*L*Imax^2; // calculation of energy stored in armature

+E_dissipated=E_stored/11; // calculation of energy dissipated per plate

+printf("\nThe number of plates in each branch is \t n=%.f",n);

+printf("\nThe total number of plates is \t N=%.f",N);

+printf("\nThe armature circuit inductance is \t L=%.2f mH",L*1E3);

+printf("\nThe energy stored in armature is \t E_stored=%.1f W",E_stored);

+printf("\nThe energy dissipated per plate is \t E_dissipated=%.2f W",E_dissipated);

+// Note : The value of time constant given in the book is 25 ms but in calculation the author has used 30 ms. Thats why answers in the book are wrong
\ No newline at end of file
diff --git a/3311/CH13/EX13.7/Ex13_7.sce b/3311/CH13/EX13.7/Ex13_7.sce
new file mode 100755
index 000000000..7fa3eeb0c
--- /dev/null
+++ b/3311/CH13/EX13.7/Ex13_7.sce
@@ -0,0 +1,13 @@
+// chapter 13

+// example 13.7

+// Design a suitable circuit

+// page-814

+clear;

+clc;

+// given

+Edc=200; // in V

+V=30; // in V

+// calculate

+n=Edc/V; // calculation of number of plates in each branch

+printf("\nThe number of plates is \t n=%.f is series",n);

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.8/Ex13_8.sce b/3311/CH13/EX13.8/Ex13_8.sce
new file mode 100755
index 000000000..43ebd819e
--- /dev/null
+++ b/3311/CH13/EX13.8/Ex13_8.sce
@@ -0,0 +1,16 @@
+// chapter 13

+// example 13.8

+// Calculate the peak value of the fault current

+// page-825-826

+clear;

+clc;

+// given

+I_2_t=150; // in A^2 sec

+f=50; // in Hz

+tc=6; // in ms

+// calculate

+tc=tc*1E-3; // changing unit from ms to s

+// since tc=3*I^2*t/Ip^2, therefore we get,

+Ip=sqrt(3*I_2_t/tc); // calculation of peak value of the fault current

+printf("\nThe peak value of the fault current is \t Ip=%.2f A",Ip);

+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH13/EX13.9/Ex13_9.sce b/3311/CH13/EX13.9/Ex13_9.sce
new file mode 100755
index 000000000..a56e45805
--- /dev/null
+++ b/3311/CH13/EX13.9/Ex13_9.sce
@@ -0,0 +1,16 @@
+// chapter 13

+// example 13.9

+// Compute the required fusing time

+// page-826-827

+clear;

+clc;

+// given

+I=250; // in A (non-repetitive surge current)

+f=50; // in Hz

+Ip=400; // in A (peak short circuit current)

+// calculate

+t=1/f; // calculation of time period

+I_subcycle=sqrt(I^2*(1/100)/t); // calculation of subcycle surge current rating

+tc=3*I_subcycle^2/Ip^2; // calculation of required fusing time

+printf("\nThe required fusing time is \t tc=%.2f ms",tc*1E3);

+// Note :The formula used in the book is wrong. The value of I_subcycle also needs to be squared but is not done in the book. Thats why the answer in the book is wrong.
\ No newline at end of file
diff --git a/3311/CH14/EX14.1/Ex14_1.sce b/3311/CH14/EX14.1/Ex14_1.sce
new file mode 100755
index 000000000..25d2bbe35
--- /dev/null
+++ b/3311/CH14/EX14.1/Ex14_1.sce
@@ -0,0 +1,37 @@
+// chapter 14
+// example 14.1
+// Determine motor terminal voltage and the value of flux as a percentage of rated flux
+// page-862-863
+clear;
+clc;
+// given
+E=220; // in V
+N1=960; // in rpm
+Ia=80; // in A (armature current)
+Ra=0.06; // in ohm (armature resistance)
+N2=620; // in rpm
+N3=1200; // in rpm
+// calculate
+Eb1=E-Ia*Ra; // calculation of bcak emf at 960 rpm
+w1=N1*2*%pi/60; // calculation of rated speed
+// since K1*phi1*w1=Eb1, therefore we get
+K1_phi1=Eb1/w1;
+// since Eb1/Eb2=N1/N2,  therefore we get
+Eb2=(N2/N1)*Eb1; // calculation of back emf at 620
+Em=Eb2+Ia*Ra; // calculation of motor terminal voltage
+w3=N3*2*%pi/60;
+// since Eb3=Ka*phi2*w3 and phi2=k*phi1, therefore we get
+// Eb3=K*phi1*w3  (i)
+// since T1=T2 or Ka*phi1*Ia1=Ka*phi2*Ia2 or Ia2=(phi1/phi2)*Ia1 or
+//   Ia2=Ia1/K   (ii)
+// since E=Eb3+Ia2*Ra , therefore Ia2=(E-Eb3)/Ra     (iii)
+// from (i) (ii) and (iii), we get  E=K*K1_phi1*w3+(Ia1/K)*Ra
+// and hence solving for K we get a quadratic equation (K1_phi1*w3)K^2-(E)K+Ia*Ra=0
+// solving the quadratic equation
+K1=(-(-E)+sqrt((-E)^2-4*K1_phi1*w3*Ia*Ra))/(2*K1_phi1*w3); // calculation of value of flux1
+K2=(-(-E)-sqrt((-E)^2-4*K1_phi1*w3*Ia*Ra))/(2*K1_phi1*w3); // calculation of value of flux2
+printf("\nThe motor terminal voltage is \t Em=%.2f V",Em);
+printf("\nThe value of flux is \t K1=%.1f ",K1);
+printf("\nThe value of flux is \t K2=%.3f ",K2);
+printf("\nThe feasible value of K is %.1f",K1)
+// Note :The answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH14/EX14.10/Ex14_10.sce b/3311/CH14/EX14.10/Ex14_10.sce
new file mode 100755
index 000000000..e45629a90
--- /dev/null
+++ b/3311/CH14/EX14.10/Ex14_10.sce
@@ -0,0 +1,43 @@
+// chapter 14
+// example 14.10
+// Determine the firing angle of the armature convertor, speed of the motor and firing angle of the field convertor
+// page-885-886
+clear;
+clc;
+// given
+P=25; // in HP (power rating of motor)
+E0=320; // in V (voltgae rating of motor)
+N=960; // in rpm
+Eac=210; // in V (ac input voltage)
+Ra=0.2; // in ohm (armature resistance)
+Rf=130; // in ohm (field resistance)
+K_a=1.2; // in V/A rad/s (motor voltage constant)
+T=110; // in Nm (torque developed)
+alpha_a=0; // in degree (firing angle for armature convertor)
+N2=1750; // in rpm
+// calculate
+Ep=Eac/sqrt(3);
+Em=sqrt(2)*Ep; // calculation of peak value of phase voltage
+Ef=(3*sqrt(3)*Em/%pi)*cosd(alpha_a);
+If=Ef/Rf;
+// since T=Ia*Ka*If, therefore we get
+Ia=T/(K_a*If);
+w=N*(2*%pi/60);
+Eb=K_a*If*w;
+Ea=Eb+Ia*Ra;
+// since Ea=(3*sqrt(3)*Em/%pi)*cosd(alpha), therefore we get
+alpha=acosd((Ea/Em)*(%pi/(3*sqrt(3))));
+Ea1=(3*sqrt(3)*Em/%pi)*cosd(alpha_a);
+Eb1=Ea1-Ia*Ra;
+w1=Eb1/(K_a*If);
+N1=w1*(60/(2*%pi));
+w2=N2*(2*%pi/60);
+// since Eb=K_a*If*w, therefore we get
+If=Eb1/(K_a*w2);
+Ef=If*Rf;
+// since Ef=(3*sqrt(3)*Em/%pi)*cosd(alpha_f), therefore we get
+alpha_f=acosd((Ef/Em)*(%pi/(3*sqrt(3))));
+printf("\nThe firing angle of the armature convertor is \talpha= %.2f degree",alpha);
+printf("\nThe speed of the motor is \t\t\t N1= %.2f rpm",N1);
+printf("\nThe firing angle of the field convertor is \t alpha_f= %.2f",alpha_f);
+// Note: The answer varies slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH14/EX14.11/Ex14_11.sce b/3311/CH14/EX14.11/Ex14_11.sce
new file mode 100755
index 000000000..9299b68f1
--- /dev/null
+++ b/3311/CH14/EX14.11/Ex14_11.sce
@@ -0,0 +1,35 @@
+// chapter 14
+// example 14.11
+// Determine the firing angle, power factor, active power and reactive power at rated speed and its 10 % and their ratio
+// page-886-887
+clear;
+clc;
+// given
+P=100; // in kW (power rating of motor)
+N=1000; // in rpm
+Ea=460; // in V
+I=300; // in A
+E=415; // in V (3 phase input voltage)
+neta=10; // in % (% of rated speed for new speed)
+// calculate
+P=P*1E3;
+Em=sqrt(2/3)*E; // calculation of peak value of phase voltage
+// since Ea=(3*sqrt(3)*Em/%pi)*cosd(alpha), therefore we get
+alpha1=acosd((Ea/Em)*(%pi/(3*sqrt(3))));
+PF1=cosd(alpha1);
+Ea_alpha=(neta/100)*Ea;
+alpha2=acosd((Ea_alpha/Em)*(%pi/(3*sqrt(3))));
+PF2=cosd(alpha2);
+Ia=P/Ea;
+I=sqrt(2/3)*Ia;
+P_active1=sqrt(3)*E*I*cosd(alpha1);
+P_reactive1=sqrt(3)*E*I*sind(alpha1);
+P_active2=sqrt(3)*E*I*cosd(alpha2);
+P_reactive2=sqrt(3)*E*I*sind(alpha2);
+ratio=P_reactive2/P_reactive1;
+printf("\nAt rated speed, the firing angle is \t alpha=%.2f degree and the power factor is \t PF=%.2f",alpha1,PF1);
+printf("\n\nAt %.f %% rated speed, the firing angle is \t alpha=%.2f degree and the power factor is \t PF=%.3f",neta,alpha2,PF2);
+printf("\n\nAt rated speed, the active power is \t P_active=%.1f kW and reactive power is \t P_reactive=%.2f kVAR",P_active1*1E-3,P_reactive1*1E-3);
+printf("\n\nAt %.f %% rated speed, the active power is \t P_active=%.2f kW and reactive power is \t P_reactive=%.2f kVAR",neta,P_active2*1E-3,P_reactive2*1E-3);
+printf("\n\nThe ratio of reactive power at  %.f %% rated speed and rated speed is %.2f",neta,ratio);
+// Note: The answer vary slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH14/EX14.12/Ex14_12.sce b/3311/CH14/EX14.12/Ex14_12.sce
new file mode 100755
index 000000000..85216256d
--- /dev/null
+++ b/3311/CH14/EX14.12/Ex14_12.sce
@@ -0,0 +1,30 @@
+// chapter 14
+// example 14.12
+// Determine the range of frequencies of the chopper
+// page-893
+clear;
+clc;
+// given
+I=80; // in A
+E=480; // in V
+N=960; // in rpm
+Ra=0.25; // in ohm (armature resistance)
+Rf=120; // in ohm (field resistance)
+N1=400, N2=750; // in rpm (range of speed)
+Ton=3; // in ms
+Ef=480; // in V
+// calculate
+Ton=Ton*1E-3; // changing unit from ms to s
+If=E/Rf; // calculation of field current
+Ia=I-If; // calculation of armature current
+Eb=E-Ia*Ra; // calculation of back emf
+Eb1=(N1/N)*Eb; // calculation of back emf corresponding to N1=400 rpm
+Ea1=Eb1+Ia*Ra; // calculation of terminal voltage corresponding to N1=400 rpm
+T1=(E/Ea1)*Ton; // calculation of chopping period corresponding to N1=400 rpm
+F1=1/T1; // calculation of frequency corresponding to N1=400 rpm
+Eb2=(N2/N)*Eb; // calculation of back emf corresponding to N2=400 rpm
+Ea2=Eb2+Ia*Ra; // calculation of terminal voltage corresponding to N2=400 rpm
+T2=(E/Ea2)*Ton; // calculation of chopping period corresponding to N2=400 rpm
+F2=1/T2; // calculation of frequency corresponding to N2=400 rpm
+printf("\n\nThe range of frequencies of the chopper is \t %.2f Hz <= f <= %.2f Hz",F1,F2);
+// Note: The answer vary slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH14/EX14.2/Ex14_2.sce b/3311/CH14/EX14.2/Ex14_2.sce
new file mode 100755
index 000000000..446d5bf84
--- /dev/null
+++ b/3311/CH14/EX14.2/Ex14_2.sce
@@ -0,0 +1,24 @@
+// chapter 14
+// example 14.2
+// Compute the speed at which motor can hold the load by regenerative braking
+// page-863-864
+clear;
+clc;
+// given
+T=100; // in Nm (torque)
+E=220; // in V
+N1=960; // in rpm
+Ia=80; // in A (armature current)
+Ra=0.06; // in ohm (armature resistance)
+// calculate
+Eb1=E-Ia*Ra; // calculation of bcak emf at 960 rpm
+w1=N1*2*%pi/60; // calculation of rated speed
+T1=Eb1*Ia/w1; // calculation of rated motor torque 
+// since T=Ka*phi*Ia, therefore we get
+Ka_phi=T1/Ia;
+Ia2=T/Ka_phi; // calculation of armature current at T=100 Nm
+Eb2=E+Ia2*Ra; // calculation of corresponding back emf
+w2=(Eb2/Eb1)*w1; // calculation of speed at which motor can hold the load by regenerative braking
+N2=w2*(60/(2*%pi));
+printf("\nThe speed at which motor can hold the load by regenerative braking is \t w2=%.2f rad/s or \t N2=%.f rpm",w2,N2)
+// Note :The value of torque given is T=100 Nm but the author has used T=1000 Nm in the calculation. Thats why the answer in the book is wrong
\ No newline at end of file
diff --git a/3311/CH14/EX14.3/Ex14_3.sce b/3311/CH14/EX14.3/Ex14_3.sce
new file mode 100755
index 000000000..1a11d97cc
--- /dev/null
+++ b/3311/CH14/EX14.3/Ex14_3.sce
@@ -0,0 +1,39 @@
+// chapter 14
+// example 14.3
+// Compute the field current, firing angle of the convertor and the input power factor
+// page-864-865
+clear;
+clc;
+// given
+E=230; // in V
+f=50; // in Hz
+La=0.06; // in H (armature inductance)
+Ra=0.3; // in ohm (armature resistance)
+Ka=0.9; // in V/A rad/s (motor voltage constant)
+Rf=104; // in ohm (field resistance)
+T_L=50; // in Nm (load torque)
+N=800; // in rpm (speed)
+alpha0=0; // in radian (firing angle for maximum field voltage)
+// calculate
+Em=E*sqrt(2); // calculation of peak voltage
+Ef=(Em/%pi)*(1+cos(alpha0)); // calculation of maximum field voltage
+If=Ef/Rf; // calculation of field current
+Ia=T_L/(Ka*If); // calculation of armature current
+w=N*(2*%pi/60); // calculation of angular speed
+Eb=Ka*w*If; // calculation of back emf
+Ea=Eb+Ia*Ra; // calculation of armature voltage
+// since Ea=(Em/%pi)*(1+cos(alpha)), therefore we get
+alpha=acosd(Ea*(%pi/Em)-1); // calculation of firing angle
+P0=Ea*Ia; // calculation of output power
+Pa=P0; // calculation of power from supply
+Irms=sqrt((2/(2*%pi))*Ia^2*integrate('1','wt',alpha*(%pi/180),%pi)); // calculation of rms current
+EI=E*Irms; // calculation of volt-ampere rating
+Pf=Pa/(EI); // calculation of power factor
+printf("\nThe field current is \t\t\t If=%.2f A",If);
+printf("\nThe firing angle of the convertor is \t alpha=%.f degree",alpha);
+printf("\nThe power factor is \t\t\t Pf=%.2f",Pf);
+if Pf>0 then
+    printf(" (lagging)");
+else
+    printf(" (leading)");
+end
\ No newline at end of file
diff --git a/3311/CH14/EX14.4/Ex14_4.sce b/3311/CH14/EX14.4/Ex14_4.sce
new file mode 100755
index 000000000..72a878a27
--- /dev/null
+++ b/3311/CH14/EX14.4/Ex14_4.sce
@@ -0,0 +1,40 @@
+// chapter 14
+// example 14.4
+// fig. 14.13
+// Determine motor torque, speed of the motor, supply power factor, firing angle and power fed back to the supply
+// page-865-866
+clear;
+clc;
+// given
+HP=10; // in HP (power of motor)
+E=210; // in V
+N=1000; // in rpm (speed)
+Ia=30; // in A (armature current)
+Ra=0.25; // in ohm (armature resistance)
+Es=230; // in V (supply voltage)
+Ka_phi=0.172; // in V/rpm (motor voltage constant)
+alpha=45; // in degree
+// calculate
+Em=Es*sqrt(2); // calculation of peak voltage
+// part- (a)
+Ka_phi_rad=Ka_phi*(60/(2*%pi)); // changing unit from V/rpm to V/rad/s
+T=Ka_phi_rad*Ia; // calculation of motor torque
+Ea=(2*Em/%pi)*cosd(alpha); // calculation of armature voltage
+Eb=Ea-Ia*Ra; // calculation of back emf
+N=Eb/Ka_phi; // calculation of speed
+EI=Es*Ia; // calculation of volt-ampere rating
+Ps=Ea*Ia; // calculation of supplied power
+Pf=Ps/EI; // calculation of power factor
+printf("\nThe motor torque is \t\t T=%.1f Nm",T);
+printf("\nThe speed of the motor is \t N=%.2f rpm",N);
+printf("\nThe supply power factor is \t Pf=%.2f",Pf);
+// part  (b)
+Ea2=-Eb+Ia*Ra; // calculation of back emf when in regenerative action Here minus sign indicates regenerative action
+// since Ea=(2*Em/%pi)*cosd(alpha), therefore we get
+alpha2=acosd(Ea2*(%pi/(2*Em))); // calculation of corresponding firing angle
+Pg=Eb*Ia; // calculation of power from dc machine
+Pr=Ia^2*Ra; // calculation of power lost in armature resistance
+Ps=Pg-Pr; // calculation of supplied power
+printf("\n\nThe firing angle to keep the motor current at its rated value is \t alpha2=%.2f degree",alpha2);
+printf("\nThe fpower fed back from the supply is \t Ps=%.1f W",Ps);
+// Note :The answers vary due to precise calculations
\ No newline at end of file
diff --git a/3311/CH14/EX14.5/Ex14_5.sce b/3311/CH14/EX14.5/Ex14_5.sce
new file mode 100755
index 000000000..e62f1abf4
--- /dev/null
+++ b/3311/CH14/EX14.5/Ex14_5.sce
@@ -0,0 +1,34 @@
+// chapter 14
+// example 14.5
+// What should be firing angle different speeds and calculate the motor speed
+// page-866-867
+clear;
+clc;
+// given
+Ea=210; // in V
+N=1200; // in rpm (speed)
+Ia=10; // in A (armature current)
+Ra=1.5; // in ohm (armature resistance)
+Es=230; // in V (supply voltage)
+N1=800; // in rpm (rated torque)
+N2=1200; // in rpm (braking torque)
+alpha3=165; // in degree
+// calculate
+Em=Es*sqrt(2); // calculation of peak voltage
+Eb=Ea-Ia*Ra; // calculation of rated back emf
+w=abs(N2)*(2*%pi/60); // calculation of rated angular speed
+Ka_phi=Eb/w; // calculation of motor voltage constant
+Eb1=(N1/N2)*Eb; // calculation of back emf at speed N1
+Ea1=Eb1+Ia*Ra; // calculation of armature voltage at speed N1
+// since Ea=(2*Em/%pi)*cosd(alpha), therefore we get
+alpha1=acosd(Ea1*(%pi/(2*Em))); // calculation of firing angle at speed N1
+Ea2=-Eb+Ia*Ra; // calculation of armature voltage at speed N2
+alpha2=acosd(Ea2*(%pi/(2*Em))); // calculation of firing angle at speed N2
+Ea3=(2*Em/%pi)*cosd(alpha3); // calculation of armature voltage at aplha3
+Eb3=Ea3-Ia*Ra; // calculation of back emf at alpha3
+w3=abs(Eb3/Ka_phi); // calculation of speed at alpha3
+N3=w3*(60/(2*%pi)); // calculation of speed in rpm
+printf("\nThe firing angle at N1=%.f rpm is \t alpha1=%.2f degree",N1,alpha1);
+printf("\nThe firing angle at N2=%.f rpm is \t alpha2=%.2f degree",N2,alpha2);
+printf("\n\nThe speed of the motor is \t w3=%.2f rad/s or \t N3=%.1f rpm",w3,N3);
+// Note : The answers vary slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH14/EX14.6/Ex14_6.sce b/3311/CH14/EX14.6/Ex14_6.sce
new file mode 100755
index 000000000..bf990385f
--- /dev/null
+++ b/3311/CH14/EX14.6/Ex14_6.sce
@@ -0,0 +1,24 @@
+// chapter 14
+// example 14.6
+// Determine the motor speed
+// page-867-868
+clear;
+clc;
+// given
+E=240; // in V
+alpha1=110; // in degree (triggering angle)
+alpha2=50; // in degree
+T=1.8; // in Nm (torque)
+Ka_phi=1; // in Nm/A (torque motor characteristics)
+Ra=6; // in ohm (armature resistance)
+// calculate
+Em=E*sqrt(2); // calculation of peak voltage
+Ia=T/Ka_phi;
+VARIABLE=(1/%pi)*Em*integrate('sin(wt)','wt',alpha1*(%pi/180),%pi);
+// since Ea=(VARIABLE+Eb*%pi*(alpha1-alpha2)/(%pi*180)) and Eb=Ea-Ia*Ra, putting the value in it, we get
+// Eb=VARIABLE+Eb*(alpha1-alpha2)/180)-Ia*Ra, or
+// Eb-Eb*(alpha1-alpha2)/180=VARIABLE/%pi-Ia*Ra or
+Eb=(VARIABLE-Ia*Ra)/(1-(alpha1-alpha2)/180); // calculation of back emf
+w=Eb/Ka_phi; // calculation of motor speed in rad/s
+N=w*(60/(2*%pi)); // calculation of motor speed in rpm
+printf("\n\nThe motor speed is \t w=%.2f rad/s or \t N=%.f rpm",w,N);
\ No newline at end of file
diff --git a/3311/CH14/EX14.7/Ex14_7.sce b/3311/CH14/EX14.7/Ex14_7.sce
new file mode 100755
index 000000000..d987c7aa0
--- /dev/null
+++ b/3311/CH14/EX14.7/Ex14_7.sce
@@ -0,0 +1,27 @@
+// chapter 14
+// example 14.7
+// Determine the triggering angle of the convertor 
+// page-868
+clear;
+clc;
+// given
+P=80; // in kW (power rating of motor)
+E=440; // in V
+N1=800; // in rpm
+N2=600; // in rpm
+neta=75; // in % (% torque with respect to rated torque)
+Eb1=410; // in V (back emf)
+Eac=415; // in V (three-phase input)
+// calculate
+P=P*1E3; // changing unit from kW to W
+Em=sqrt(2/3)*Eac; // calculation of peak value of input voltage
+// since Eb1/Eb2=N1/N2, therefore we get
+Eb2=Eb1*(N2/N1); // calculation of back emf corresponding to N2=600 rpm
+Ia=P/E; // calculation of armature current
+// since Eb1=E-Ia*Ra, therefore we get
+Ra=(E-Eb1)/Ia; // calculation of armature resistance
+Ea=Eb2+((neta/100)*Ia*Ra); // calculation of armature volage
+// since Ea=(3*sqrt(3)/%pi)*Em*cosd(alpha), therefore we get
+alpha=acosd((Ea/Em)*(%pi/(3*sqrt(3)))); // calculation of triggering angle of the convertor 
+printf("\n\nThe triggering angle of the convertor  is \t alpha=%.2f rdegree",alpha);
+// Note: The answer varies slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH14/EX14.8/Ex14_8.sce b/3311/CH14/EX14.8/Ex14_8.sce
new file mode 100755
index 000000000..c7b8ed502
--- /dev/null
+++ b/3311/CH14/EX14.8/Ex14_8.sce
@@ -0,0 +1,44 @@
+// chapter 14
+// example 14.8
+// Determine no load speeds, firing angle, supply power factor and the speed regulation
+// page-868-870
+clear;
+clc;
+// given
+P=150; // in HP (power rating of motor)
+E0=650; // in V (voltgae rating of motor)
+N1=1750; // in rpm
+Eac=460; // in V (three-phase input)
+Ia=170; // in A (rated armature current)
+Ra=0.099; // in ohm (armature resistance)
+La=0.73; // in mH (armature inductance)
+Ka_phi=0.33; // in V/rpm (motor voltage constant)
+alpha1=0, alpha2=30; // in degrees (firing angle)
+neta=10; // in % (armature current at no load as a percentage of rated armature current)
+// calculate
+E=Eac/sqrt(3);
+Em=E*sqrt(2);
+Ea1=(3*sqrt(3)/%pi)*Em*cosd(alpha1);
+Eb1=Ea1-Ia*Ra;
+N_NL1=Eb1/Ka_phi;
+Ea2=(3*sqrt(3)/%pi)*Em*cosd(alpha2);
+Eb2=Ea2-Ia*Ra;
+N_NL2=Eb2/Ka_phi;
+Eb3=Ka_phi*N1;
+Ea3=Eb3+Ia*Ra;
+// since Ea=(3*sqrt(3)/%pi)*Em*cosd(alpha), therefore we get
+alpha3=acosd((Ea3/Em)*(%pi/(3*sqrt(3))));
+I_A=sqrt((1/%pi)*Ia^2*(2*%pi/3));
+VA=3*E*I_A;
+Ps=Ea3*Ia;
+PF=Ps/VA;
+Eb4=Ea3-((neta/100)*Ia*Ra);
+N_NL3=Eb4/Ka_phi;
+SR=((N_NL3-N1)/N1)*100;
+printf("\nThe no load speeds are");
+printf("\n\t\t\t For alpha=%.f degree, N_NL= %.2f rpm",alpha1,N_NL1);
+printf("\n\t\t\t For alpha=%.f degree, N_NL= %.2f rpm",alpha2,N_NL2);
+printf("\n\nThe firing angle to obtain a speed of N=%.f rpm is \t alpha= %.2f degree",N1,alpha3);
+printf("\nThe supply power factor is \t\t\t\t PF= %.2f",PF);
+printf("\nThe speed regulation is \t\t\t\t\t SR= %.2f %%",SR);
+// Note: The answer varies slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH14/EX14.9/Ex14_9.sce b/3311/CH14/EX14.9/Ex14_9.sce
new file mode 100755
index 000000000..e322eacff
--- /dev/null
+++ b/3311/CH14/EX14.9/Ex14_9.sce
@@ -0,0 +1,41 @@
+// chapter 14
+// example 14.9
+// Determine motor torque, motor current and supply power factor
+// page-878-879
+clear;
+clc;
+// given
+P=20; // in HP (power rating of motor)
+E0=650; // in V (voltgae rating of motor)
+N=1000; // in rpm
+Ra=0.25; // in ohm (armature resistance)
+K_af=0.03; // in NmA^2
+K_res=0.075; // in Vs/rad
+Es=230; // in V (supply voltage)
+alpha=30; // in degree (firing angle)
+// calculate
+Em=sqrt(2)*Es; // calculation of peak value of supply voltage
+// part- (a) // semiconvertor controlled dc drive
+w=N*(2*%pi/60); // calculation of angular speed
+T=K_af*((((Em/%pi)*(1+cosd(alpha)))-K_res*w)/(Ra+K_af*w))^2; // calculation of motor torque
+Ia=sqrt(T/K_af); // calculation of motor current
+Ea=(sqrt(2)*Es/%pi)*(1+cosd(alpha)); // calculation of motor terminal voltage
+Ps=Ea*Ia; // calculation of input power
+VA=Es*Ia*sqrt(5/6); // calculation of input volt-ampere
+PF=Ps/VA; // calculation of supply power factor
+printf("\nFor semiconvertor controlled DC drives");
+printf("\nThe motor torque is \t\t T= %.2f Nm",T);
+printf("\nThe motor current is \t\t Ia= %.2f A",Ia);
+printf("\nThe supply power factor is \t PF= %.2f",PF);
+// part  (b)
+T=K_af*((((2*Em/%pi)*cosd(alpha))-K_res*w)/(Ra+K_af*w))^2; // calculation of motor torque
+Ia=sqrt(T/K_af); // calculation of motor current
+Ea=(2*sqrt(2)*Es/%pi)*cosd(alpha); // calculation of motor terminal voltage
+Ps=Ea*Ia; // calculation of input power
+VA=Es*Ia; // calculation of input volt-ampere
+PF=Ps/VA; // calculation of supply power factor
+printf("\n\nFor fullconvertor controlled DC drives");
+printf("\nThe motor torque is \t\t T= %.2f Nm",T);
+printf("\nThe motor current is \t\t Ia= %.2f A",Ia);
+printf("\nThe supply power factor is \t PF= %.2f",PF);
+// Note: The answer varies slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH15/EX15.1/Ex15_1.sce b/3311/CH15/EX15.1/Ex15_1.sce
new file mode 100755
index 000000000..5cb74cbaa
--- /dev/null
+++ b/3311/CH15/EX15.1/Ex15_1.sce
@@ -0,0 +1,17 @@
+// chapter 15
+// example 15.1
+// Determine the new value of torque developed by motor
+// page-912
+clear;
+clc;
+// given
+T1=1500; // in sync Watts
+f1=50; // in Hz
+N=1440; // in rpm
+NS=1500; // in rpm (synchronoous speed)
+f2=75; // in Hz
+// calculate
+// since T1/T2=f2/f1, therefore we get
+T2=(f1/f2)*T1;
+printf("\n\nThe new value of torque developed by motor is \t T2=%.2f sync. watts",T2);
+// Note: The answer vary slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH15/EX15.2/Ex15_2.sce b/3311/CH15/EX15.2/Ex15_2.sce
new file mode 100755
index 000000000..bca14e58e
--- /dev/null
+++ b/3311/CH15/EX15.2/Ex15_2.sce
@@ -0,0 +1,45 @@
+// chapter 15
+// example 15.2
+// Determine the angle of firing advance in different cases, voltage ratio and power flow
+// page-958-959
+clear;
+clc;
+// given
+P=6; // number of poles
+f=50; // in Hz
+N1=600, N2=800; // in rpm
+E=600; // in V open circuit standstill slip-ring voltage
+Es=415; // in V (supply voltage)
+gama1=10; // in degree (overlap angle in rectifier)
+gama2=5; // in degree (overlap angle in invertor)
+V_diode=1.5; // in V (voltage drop across SCR)
+V_SCR=0.7; // in V (voltage drop across SCR)
+alpha=0; // in degree (used by the author in the book)
+Pin=100; // assumption as done in the book
+// calculate
+Ns=(f/P)*120; // calculation of synchronous speed
+S1=(Ns-N1)/Ns; // calculation of slip corresponding to N1=600
+Er1=N1*S1; // calculation of rotor voltage corresponding to N1=600
+Edc1=(P*Er1*sqrt(2)/%pi)*sin(%pi/P); // calculation of dc link voltage corresponding to N1=600
+Edc_inv1=Edc1;
+Emax=Es*sqrt(2);
+// since Edc_inv=(P*Emax/(2*%pi))*sin(%pi/P)*(cos(Beta)+cos(Beta-gama)), and gama=0,  therefore we get
+Beta1=(acosd((2*%pi/(P*Emax*sin(%pi/P)))*Edc_inv1/2)); // calculation of angle of firing advance corresponding to N1=600
+S2=(Ns-N2)/Ns; // calculation of slip corresponding to N2=800
+Er2=N2*S2; // calculation of rotor voltage corresponding to N2=800
+Edc2=(P*Er2*sqrt(2)/%pi)*sin(%pi/P); // calculation of dc link voltage corresponding to N2=800
+Edc_inv2=Edc2;
+// since Edc_inv=(P*Emax/(2*%pi))*sin(%pi/P)*(cos(Beta)+cos(Beta-gama)), and gama=0,  therefore we get
+Beta2=(acosd((2*%pi/(P*Emax*sin(%pi/P)))*Edc_inv2/2)); // calculation of angle of firing advance corresponding to N2=800
+Edc3=(P*Emax/(2*%pi))*sin(%pi/P)*(cos(alpha)+cos(alpha+gama1))-2*V_SCR;
+Beta3=acosd(((2*%pi/(P*Emax*sin(%pi/P)))*(Edc3-2*V_diode))/(2*cosd(gama2/2)))+gama2/2;
+K=Es/Er1;
+P0_rotor=Pin*S1;
+P0_shaft=Pin-P0_rotor;
+printf("\n\nThe angle of firing advance corresponding to N1=%.f rpm is \t Beta1=%.1f degree",N1,Beta1);
+printf("\nThe angle of firing advance corresponding to N2=%.f rpm is \t Beta2=%.1f degree",N2,Beta2);
+printf("\nThe angle of firing advance in overlapping case is \t\t Beta3=%.1f degree",Beta3);
+printf("\n\nThe transfromer ratio is \t K=%.2f",K);
+printf("\n\nThe power out of the rotor is \t P0_rotor=%.f %% of power input to the stator",P0_rotor);
+printf("\nThe shaft output power is \t P0_shaft=%.f %% of power input to the stator",P0_shaft);
+// Note: The answer in the book is wrong for Beta3 due to use of wrong values of Emax and gama1 in the calculation. I have used the correct values
\ No newline at end of file
diff --git a/3311/CH15/EX15.3/Ex15_3.sce b/3311/CH15/EX15.3/Ex15_3.sce
new file mode 100755
index 000000000..6448f2cb4
--- /dev/null
+++ b/3311/CH15/EX15.3/Ex15_3.sce
@@ -0,0 +1,45 @@
+// chapter 15
+// example 15.3
+// Determine the input voltage, armature current, excitation voltage, torque angle and pull-out torque
+// page-977-978
+clear;
+clc;
+// given
+P=6; // number of poles
+f=50; // in Hz
+E=400; // in V
+Xs=%i*2; // in ohm (reactance per phase)
+T_L=300; // in Nm
+N=1000; // in rpm
+f_inv=40; // in Hz (invertor frequency)
+Nm=560; // in rpm (motor speed)
+phi=0; // in degree (used in the book)
+// calculate
+Pf=cosd(phi);
+Es=E/sqrt(3);
+Eb=Es;
+Ea_rated=Es;
+w=2*%pi*f;
+ws=2*w/P;
+wb=ws;
+Ns=(60/(2*%pi))*ws;
+K=Eb/wb;
+T_L1=T_L*(Nm/N)^2;
+wm1=Nm*(2*%pi/60);
+ws1=wm1;
+P0=T_L1*wm1;
+Ea=K*ws1;
+// since P0=3*Ea*Ia*Pf, therefore we get
+Ia=P0/(3*Ea*Pf);
+Ef=Ea-Ia*(Xs);
+Ef_abs=abs(Ef);
+Ef_phase=atand(imag(Ef)/real(Ef));
+del=Ef_phase;
+T_P=3*Ea*Ef_abs/(2*wm1);
+printf("\nThe input voltage is \t\t Ea=%.2f V",Ea);
+printf("\nThe armature current is \t Ia=%.2f A",Ia);
+printf("\nThe excitation voltage is \t Ef=%.2f V <%.2f degree",Ef_abs,Ef_phase);
+printf("\nThe torque angle is \t\t %.2f degree",del);
+printf("\nThe pull-out torque is \t\t T_P=%.2f Nm",T_P);
+// Note: 1. In the book, the value of N given is N=100 rpm, but hte author hase used N=1000 rpm while solving. I have also used N=1000 rpm to make the answers to have practical values.
+//       2. The answers in the book vary slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH16/EX16.1/Ex16_1.sce b/3311/CH16/EX16.1/Ex16_1.sce
new file mode 100755
index 000000000..80b358018
--- /dev/null
+++ b/3311/CH16/EX16.1/Ex16_1.sce
@@ -0,0 +1,22 @@
+// chapter 16
+// example 16.1

+// Determine kVA rating of invertor, Wattage of the rectifier and A-H rating of  battery

+// page-996

+clear;

+clc;

+// given

+Load=600; // in W

+PF=0.8; // (lagging power factor)

+efficiency=80; // in %

+Edc=24; // in V

+backup_time=30; // in min

+// calculate

+// since PF=Load/kVA_rating, therefore we get

+kVA_rating=Load/PF; // calculation of kVA rating of invertor

+wattage=kVA_rating*PF/(efficiency/100); // calculation of Wattage of the rectifier

+Idc=kVA_rating/Edc; // calculation of dc current

+AH_rating=Idc*backup_time/60; // calculation of A-H rating of  battery

+printf("\nThe kVA rating of invertor is \t\t %.2f kW",kVA_rating*1E-3);

+printf("\nThe Wattage of the rectifier is \t %.2f kW",wattage*1E-3);

+printf("\nThe A-H rating of  battery is \t\t %.2f AH",AH_rating);

+// The battery voltage is given as Edc=24 V but the author has  used Edc=48 V. Thats why the answer in the book for AH_rating is wrong.
\ No newline at end of file
diff --git a/3311/CH16/EX16.10/Ex16_10.sce b/3311/CH16/EX16.10/Ex16_10.sce
new file mode 100755
index 000000000..3dc6a0344
--- /dev/null
+++ b/3311/CH16/EX16.10/Ex16_10.sce
@@ -0,0 +1,19 @@
+// chapter 16
+// example 16.10

+// fig. 16.20

+// Determine rms current and peak reverse voltage

+// page-1028-1029

+clear;

+clc;

+// given

+P0=500; // in MW

+E=250; // in kV

+// calculate

+P0=P0*1E6; // changing unit from MW to W

+E=E*1E3; // changing unit from kV to V

+Id=P0/(2*E); // calculation of direct current

+Irms=Id/sqrt(3); // calculation of rms current

+E_line_max=E/2; // calculation of maximum line voltage
 for 6 pulse group
+PIV=E_line_max*(%pi/3); // calculation of peak reverse voltage

+printf("\nThe rms current is \t\t Irms=%.2f A",Irms);

+printf("\nThe peak reverse voltage is \t PIV=%.f kV",PIV*1E-3);

diff --git a/3311/CH16/EX16.11/Ex16_11.sce b/3311/CH16/EX16.11/Ex16_11.sce
new file mode 100755
index 000000000..6fcf0fe57
--- /dev/null
+++ b/3311/CH16/EX16.11/Ex16_11.sce
@@ -0,0 +1,23 @@
+// chapter 16

+// example 16.11

+// Determine depth of heating and heat generated per unit surface area

+// page-1036

+clear;

+clc;

+// given

+L=10; // in cm (length)

+d=1; // in cm  (diameter)

+N=15; // number of turns

+I=80; // in A

+f=200; // in kHz

+ur=1; // relative permeability

+rho=5E-8; // in ohm-m (resistivity)

+// calculate

+L=L*1E-2; // changing unit from cm to m

+d=d*1E-2; // changing unit from cm to m

+f=f*1E3; // changing unit from KHz to Hz

+del=503*sqrt(rho/(ur*f)); // calculation of depth of heating

+H=2*%pi*(N*I/L)^2*sqrt(rho*ur*f/1E7); // calculation of heat generated per unit surface area

+printf("\nThe depth of heating is \t\t\t del=%.3f mm",del*1E3);

+printf("\nThe heat generated per unit surface area is \t H=%.2f kW/m^2",H*1E-3);

+// Note : The value of L given is L=10 cm but the author has used L=1 cm in the calculation. Thats why answer in the book is wrong.
\ No newline at end of file
diff --git a/3311/CH16/EX16.12/Ex16_12.sce b/3311/CH16/EX16.12/Ex16_12.sce
new file mode 100755
index 000000000..64e8213b6
--- /dev/null
+++ b/3311/CH16/EX16.12/Ex16_12.sce
@@ -0,0 +1,15 @@
+// chapter 16
+// example 16.12
+// Determine supply frequency
+// page-1037
+clear;

+clc;

+// given
+del=2.5; // in mm (depth of heating)
+rho=5E-5; // in ohm-cm (resistivity)
+ur=1; // relative permeability
+// calculate

+del=del*1E-3; // changing unit from mm to m
+rho=rho*1E-2; // changing unit from ohm-cm to ohm-m
+f=(rho/ur)*(503/del)^2; // calculation of supply frequency
+printf("\nThe supply frequency is \t f=%.2f kHz",f*1E-3);
\ No newline at end of file
diff --git a/3311/CH16/EX16.13/Ex16_13.sce b/3311/CH16/EX16.13/Ex16_13.sce
new file mode 100755
index 000000000..4ba56f22b
--- /dev/null
+++ b/3311/CH16/EX16.13/Ex16_13.sce
@@ -0,0 +1,27 @@
+// chapter 16
+// example 16.13
+// Determine voltage and current
+// page-1041
+clear;
+clc;
+// given
+l=25, b=15, t=1; // in cm (dimensions of piece)
+P=1; // in kW
+Er=4; // relative permittivity
+PF=0.6; // power factor
+f=40; // in MHz
+Eo=8.854E-12; // absolute permittivity
+// calculate
+l=l*1E-2; // changing unit from cm to m
+b=b*1E-2; // changing unit from cm to m
+t=t*1E-2; // changing unit from cm to m
+P=P*1E3; // changing unit from kW to W
+f=f*1E6; // changing unit from MHz to Hz
+A=l*b; // calculation of area
+C=Eo*Er*A/t; // calculation of capacitance
+// since P=2*%pi*f*C*V^2*PF, therefore we get
+V=sqrt(P/(2*%pi*f*C*PF)); // calculation of voltage
+Xc=1/(2*%pi*f*C); // calculation of capacitive reactance
+I=V/Xc; // calculation of current
+printf("\nThe voltage is \t V=%.2f V",V);
+printf("\nThe current is \t I=%.2f A",I);
\ No newline at end of file
diff --git a/3311/CH16/EX16.14/Ex16_14.sce b/3311/CH16/EX16.14/Ex16_14.sce
new file mode 100755
index 000000000..9455ab440
--- /dev/null
+++ b/3311/CH16/EX16.14/Ex16_14.sce
@@ -0,0 +1,16 @@
+// chapter 16
+// example 16.14
+// Determine supply frequency
+// page-1041
+clear;
+clc;
+// given
+C=5.3; // in uF
+V=600; // in V
+I=100; // in A
+// calculate
+C=C*1E-6; // changing unit from uF to F
+Xc=V/I;
+// since Xc=1/(2*%pi*f*C), therefore we get
+f=1/(2*%pi*C*Xc); // calculation of supply frequency
+printf("\nThe supply frequency is \t f=%.f kHz",f*1E-3);
\ No newline at end of file
diff --git a/3311/CH16/EX16.15/Ex16_15.sce b/3311/CH16/EX16.15/Ex16_15.sce
new file mode 100755
index 000000000..361d8a00b
--- /dev/null
+++ b/3311/CH16/EX16.15/Ex16_15.sce
@@ -0,0 +1,21 @@
+// chapter 16
+// example 16.15
+// fig. Ex 16.15
+// Calculate the value of load resistance, commutating capacitor and resistance connected in series
+// page-1046
+clear;
+clc;
+// given
+Edc=50; // in V (supply voltage)
+I_L=10; // in A (load current)
+Toff=20; // in us (turn-off time)
+I_H=5; // in mA (holding current)
+// calculate
+Toff=Toff*1E-6; // changing unit from us to s
+I_H=I_H*1E-3; // changing unit from mA to A
+R2=Edc/I_H; // calculation of resistance connected in series
+R1=Edc/I_L; // calculation of load resistance
+C=1.5*Toff*I_L/Edc; // calculation of ommutating capaitor
+printf("\nThe value of resistance connected in series is \t R2=%.f k-ohm",R2*1E-3);
+printf("\nThe value of load resistance is \t R1=%.f ohm",R1);
+printf("\nThe value of commutating capacitor is \t C>=%.f uF",C*1E6);
\ No newline at end of file
diff --git a/3311/CH16/EX16.16/Ex16_16.sce b/3311/CH16/EX16.16/Ex16_16.sce
new file mode 100755
index 000000000..2372f6b0b
--- /dev/null
+++ b/3311/CH16/EX16.16/Ex16_16.sce
@@ -0,0 +1,19 @@
+// chapter 16
+// example 16.16
+// What will be the firing angle and output power available
+// page-1051
+clear;
+clc;
+// given
+f=50; // in Hz
+neta=60; // in % 
+T=0.24; // in s (repition period)
+// calculate
+// part (i) can not be solved
+// since T=0.24 s represents 12 cycles at 50 Hz or T=24 half cycles, therefore 
+T=24;
+// since Pload/Pmax=N/24, therefore
+N1=1, N2=24
+Pload1=N1/T;
+Pload2=N2/T;
+printf("The available power range from %.2f %% of Pmax (N=%.f) to %.f %% of Pmax (N=%.f) varying in steps of %.2f %% of Pmax",Pload1*1E2,N1,Pload2*1E2,N2,Pload1*1E2);
diff --git a/3311/CH16/EX16.2/Ex16_2.sce b/3311/CH16/EX16.2/Ex16_2.sce
new file mode 100755
index 000000000..afe83c53e
--- /dev/null
+++ b/3311/CH16/EX16.2/Ex16_2.sce
@@ -0,0 +1,25 @@
+// chapter 16
+// example 16.2

+// Select a suitable battery

+// page-996-997

+clear;

+clc;

+// given

+UPS_rating=20; // in kVA

+backup_time=15; // in min

+efficiency=85; // in %

+PF=0.8; // (lagging power factor)

+Edc1=147, Edc2=190; // in V (Battery voltage range)

+V_cell=1.75; // in V (voltage per cell)

+N=6; // in cell groups per jar

+// calculate

+
+Battery_kW=UPS_rating*PF/(efficiency/100); // calculation of battery power

+num_cell=Edc1/V_cell; // calculation of number of cells

+num_jar=num_cell/N; // calculation of number of jars

+cell_size_kW=Battery_kW/num_cell // calculation of cell size

+printf("\nThe battery power is \t %.2f kW",Battery_kW);

+printf("\nThe number of cells is \t %.f",num_cell);

+printf("\nThe number of jars is \t %.f",num_jar);

+printf("\nThe cell size is \t %.3f kW",cell_size_kW);

+printf("\n\nBased on this data, we can choose 90 A-H battery which has 0.255 kW discharge rate at %.f min back-up time",backup_time);
\ No newline at end of file
diff --git a/3311/CH16/EX16.3/Ex16_3.sce b/3311/CH16/EX16.3/Ex16_3.sce
new file mode 100755
index 000000000..2ecd8eb90
--- /dev/null
+++ b/3311/CH16/EX16.3/Ex16_3.sce
@@ -0,0 +1,18 @@
+// chapter 16
+// example 16.3

+// Determine AH efficiency and WH efficiency

+// page-997

+clear;

+clc;

+// given

+V_cell=2; // in V (voltage of lead acid cell)

+I_discharge=35; // in A (discharge current)

+T_discharge=5; // in Hrs

+Eavg=1.95; // in V

+I_charge=45; // in A (4charge current)

+T_charge=4; // in Hrs

+// calculate

+AH_efficiency=((I_discharge*T_discharge)/(I_charge*T_charge))*100; // calculation of AH efficiency

+WH_efficiency=AH_efficiency*Eavg/V_cell; // calculation of WH efficiency


+printf("\nThe AH efficiency is \t %.2f %%",AH_efficiency);

+printf("\nThe WH efficiency is \t %.2f %%",WH_efficiency);
\ No newline at end of file
diff --git a/3311/CH16/EX16.4/Ex16_4.sce b/3311/CH16/EX16.4/Ex16_4.sce
new file mode 100755
index 000000000..06b0cedd2
--- /dev/null
+++ b/3311/CH16/EX16.4/Ex16_4.sce
@@ -0,0 +1,25 @@
+// chapter 16
+// example 16.4

+// Determine dc supply voltage and charging current

+// page-997

+clear;

+clc;

+// given

+num_cell=18; // number of cells

+AH_output=90; // in AH (AH output per cell)

+T=10; // in Hrs

+charging_time=8; // in Hrs

+AH_efficiency=85; // in %

+V_cell=2.4; // in V (voltage per cell)

+r=0.1; // in ohm (internal resistance of battery)

+// calculate

+// since AH_efficiency=AH_output/AH_input, therefore we get

+AH_input=AH_output/(AH_efficiency/100); // calculation of input AH per cell

+// since AH_input=charging_current*charging_time, therefore we get

+charging_current=AH_input/charging_time; // calculation of charging current

+V_total=num_cell*V_cell; // calculation of total terminal voltage of 18 cells

+V_drop=r*charging_current; // calculation of voltage drop across internal resistance

+Edc=V_total+V_drop; // calculation of dc supply voltage

+printf("\nThe charging current is \t %.2f A",charging_current);

+printf("\nThe dc supply voltage is \t %.3f V",Edc);

+// Note: the answers vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH16/EX16.5/Ex16_5.sce b/3311/CH16/EX16.5/Ex16_5.sce
new file mode 100755
index 000000000..a0aa10dd5
--- /dev/null
+++ b/3311/CH16/EX16.5/Ex16_5.sce
@@ -0,0 +1,32 @@
+// chapter 16
+// example 16.5

+// Calculate back-up time and charger peak output power

+// page-997-998

+clear;

+clc;

+// given

+VA_rating=6; // in kVA

+V=230; // in V

+E=144; // in V

+PF=0.8;

+neta=0.85; // invertor efficiency

+AH_rating=500; // in AH

+E1=10.6, E2=13.4; // in V (range of battery voltage)

+E_normal=12; // in V (normal battery voltage)

+T=4; // in Hrs (charging time)

+t=8; // in Hrs

+capacity_derating=0.5;

+// calculate

+VA_rating=VA_rating*1E3;
+Battery_kW=VA_rating*PF/neta; // calculation of battery power

+num_Battery=E/E_normal; // calculation of number of batteries

+// considering worst case for calculation of discharge current

+Total_battery_voltage=E1*num_Battery; // calculation of total battery voltage

+// since Battery_kW=Total_battery_voltage*I_dc, therefore we get,

+I_dc=Battery_kW/Total_battery_voltage; // calculation of battery discharge current 

+T_backup=AH_rating*capacity_derating/I_dc; // calculation of back-up time

+Ic=AH_rating*capacity_derating/T; // calculation of charging current

+P_peak=E*Ic; // calculation of charging peak power

+printf("\nThe back-up time is \t\t %.3f hours",T_backup);

+printf("\nThe charging peak power is \t %.f kW",P_peak*1E-3);

+// Note : There is calculation mistake in the book while calculating T_backup. Thats why answer in the book is wrong
\ No newline at end of file
diff --git a/3311/CH16/EX16.6/Ex16_6.sce b/3311/CH16/EX16.6/Ex16_6.sce
new file mode 100755
index 000000000..fce1638ef
--- /dev/null
+++ b/3311/CH16/EX16.6/Ex16_6.sce
@@ -0,0 +1,22 @@
+// chapter 16
+// example 16.6

+// Determine maximum duty cycle and flyback convertor turns ratio

+// page-1007

+clear;

+clc;
+// given

+fs=60; // in kHz (switching frequency)

+Esp=180; // in V (spike voltage)

+Mains=230; // in V (mains supply)

+f=50; // in Hz (supply frequency)

+E0=12; // in V

+E_DS=1200; // in V (used in the book, voltage across MOSFET)

+// calculate

+Edc=Mains*sqrt(2); // calculation of peak mains voltage

+// since E_DS=(Edc/(1-alpha_max)+Esp, therefore we get

+alpha_max=1-(Edc/(E_DS-Esp)); // calculation of maximum duty cycle

+// since E0=(alpha_max/(1-alpha_max))*(N2/N1)*Edc, therefore we get

+K=(Edc/E0)*(alpha_max/(1-alpha_max)); // calculation of flyback convertor turns ratio

+printf("\nThe maximum duty cycle is \t\t alpha_max=%.2f",alpha_max);

+printf("\nThe flyback convertor turns ratio is \t N2/N1=%.1f",K);

+// Note : the answer vary slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH16/EX16.7/Ex16_7.sce b/3311/CH16/EX16.7/Ex16_7.sce
new file mode 100755
index 000000000..dcb52872d
--- /dev/null
+++ b/3311/CH16/EX16.7/Ex16_7.sce
@@ -0,0 +1,41 @@
+// chapter 16
+// example 16.7

+// Determine average input power and current, ratings of the trasistor, primary winding indutance and number of turns, and ratings of the diode

+// page-1007-1009

+clear;

+clc;

+// given

+Edc_min=14, Edc_max=30; // in V (range of supply voltage)

+V1=12, V2=-12, // in V (output voltages)

+I1=0.6, I2=0.6; // in A (output current)

+i_1=0.1, i_2=0.5; // in A (range of load current)

+neta=80; // in % (efficiency of the convertor)

+fs=50; // in kHz (switching frequency)

+alpha_max=0.5; // assumption as done in the book

+L0=80; // in mH  (assumption as done in the book)

+N0=1100; //  (assumption as done in the book)

+// calculate

+fs=fs*1E3; // changing unit from kHz to Hz

+L0=L0*1E-3; // changing unit from mH to H

+P0=(V1*I1)+(-V2*I2); // calculation of full-load power

+Pi=P0/(neta/100); // calculation of input power

+I_avg_max=Pi/Edc_min; // calculation of maximum average input current

+I_avg_min=Pi/Edc_max; // calculation of minimum average input current

+Ic_max=2*P0/((neta/100)*Edc_min*alpha_max); // calculation of transistor current rating

+V_CE_max=Edc_max/(1-alpha_max); // calculation of transistor voltage rating

+Pd_max=V_CE_max*Ic_max; // calculation of transistor power rating

+L_prim=Edc_min*alpha_max/(Ic_max*fs); // calculation of primary inductance

+N_prim=N0*sqrt(L_prim/L0); // calculation of number of turns in primary winding

+// since E0=(alpha_max/(1-alpha_max))*(N2/N1)*Edc, therefore we get

+N_sec=(V1/Edc_min)*N_prim*((1-alpha_max)/alpha_max); // calculation of number of turns in secondary winding

+Id=(N_prim/N_sec)*Ic_max; // calculation of peak diode current

+PIV=V1+(Edc_max/(N_prim/N_sec)); // calculation of peak inverse voltage

+printf("\nThe average input power is \t Pi=%.f W",Pi);

+printf("\nThe maximum average input current is \t I_avg_max=%.3f A",I_avg_max);

+printf("\nThe minimum average input current is \t I_avg_min=%.3f A",I_avg_min);

+printf("\n\nThe ratings of the transistor are \t Ic_max=%.2f A \t V_CE_max=%.f V \t Pd_max=%.f W",Ic_max,V_CE_max,Pd_max);

+printf("\n\nThe number of turns in primary winding is \t N_prim=%.f",N_prim);

+printf("\n\nThe number of turns in secondary winding is \t N_sec=%.f",N_sec);

+printf("\n\nThe ratings of the diode are \t Id>=%.1f A \t PIV>= %.2f V",Id,PIV);

+// Note : 1.There is calculation mistake while calculating Id. Thats why answer in the book is wrong.
+//        2. The answers vary slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH16/EX16.8/Ex16_8.sce b/3311/CH16/EX16.8/Ex16_8.sce
new file mode 100755
index 000000000..56930df4d
--- /dev/null
+++ b/3311/CH16/EX16.8/Ex16_8.sce
@@ -0,0 +1,30 @@
+// chapter 16
+// example 16.8

+// Determine turn ratio of demagnetizing winding with primary winding, switch voltagae rating and dc supply current

+// page-1015

+clear;

+clc;

+// given

+E0=12; // in V

+I0=12; // in A

+fs=60; // in kHz (switching frequency)

+E=230; // in V (rectified ac mains)

+alpha_max=0.6; // maximum duty cycle

+neta1=50; // in % (spike voltage percentage)

+neta2=20; // in %

+// calculate

+fs=fs*1E3; // changing unit from kHz to Hz

+Edc=E*sqrt(2); // calculation of dc voltage

+Esp=(neta1/100)*Edc; // calculation of spike voltage

+// since alpha_max=1/(1+(N3/N1)), therefore we get

+// K=N1/N3=1/((1/alpha_max)-1),

+K=1/((1/alpha_max)-1); // calculation of turns ratio

+Vsw=Edc+K*Edc+Esp; // calculation of switch voltage

+// since K1=N1/N2=V1/V2, therefore we get

+K1=(1-(neta2/100))*Edc/E0; 

+// since I1/I2=N2/N1, therefore we get

+I1=I0/K1; // calculation of dc supply current

+printf("\nThe turn ratio of demagnetizing winding with primary winding is \t N1/N3=%.1f",K);

+printf("\nThe required switch voltage is \t\t\t\t\t\t Vsw=%.2f V",Vsw);

+printf("\nThe dc supply current at full current is \t\t\t\t I1=%.2f A",I1);

+// Note: The answer vary slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH16/EX16.9/Ex16_9.sce b/3311/CH16/EX16.9/Ex16_9.sce
new file mode 100755
index 000000000..3de75387c
--- /dev/null
+++ b/3311/CH16/EX16.9/Ex16_9.sce
@@ -0,0 +1,39 @@
+// chapter 16
+// example 16.9
+// Determine the value of coupling capacitor, verfiy if the value is acceptable or not, If not then determine the new value
+// page-1019-1020
+clear;
+clc;
+// given
+P0=200; // in W
+fs=20; // in kHz
+n=10; // turns ratio
+L=20; // in uH
+e=80; // in % (efficiency)
+E=230; // in V (used in the book)
+alpha_max=0.8; // assumption for duty cycle as done in the book
+tolerance=20; // assumption for voltage tolerance as done in the book
+// calculate
+fs=fs*1E3; // changing unit from kHz to Hz
+L=L*1E-6; // changing unit from uH to H
+L_R=n^2*L;// calculation of resonant inductance
+f_R=0.25*fs;// calculation of resonant freuquency
+Cc=1/(4*(%pi*f_R)^2*L_R);// calculation of coupling capacitor
+Edc=E*sqrt(2);// calculation of dc voltage
+Ic=2*P0/((e/100)*alpha_max*Edc);// calculation of coupling current
+I=Ic+(tolerance/100)*Ic;// calculation of worst case coupling current
+dt=alpha_max/(2*fs);
+Vc=(I/Cc)*dt;// calculation of coupling capacitor charge voltage
+// since the range of Vc is 6 to 32 V, 
+// let us assume dVc=30 V therefore, the new value of capacitor is C=I*(dt/dVc);
+dVc=30; // in V
+C=I*(dt/dVc);// calculation of new coupling capacitance
+printf("\nThe value of coupling capacitor is \t\t Cc=%.2f uF",Cc*1E6);
+printf("\nThe peak coupling capacitor charge voltage is \t vc=%.1f V",Vc);
+if Vc>=6 & Vc<=32 then
+    printf("\n\nThe value of Vc is acceptable.");
+else
+    C=I*dt/dVc;
+    printf("\nThe new value of coupling capacitor is \t\t C=%.1f uF",C*1E6);
+end
+// Note : the answer vary slightly due to round off
\ No newline at end of file
diff --git a/3311/CH2/EX2.1/Ex2_1.sce b/3311/CH2/EX2.1/Ex2_1.sce
new file mode 100755
index 000000000..3a5098742
--- /dev/null
+++ b/3311/CH2/EX2.1/Ex2_1.sce
@@ -0,0 +1,24 @@
+// chapter 2
+// example 2.1
+// fig. E2.1
+// Will the thyristor get fired
+// page-21-22
+clear;
+clc;
+// given
+I_L=50; // in mA (Latching current)
+t=50; // in us (duration of fireing pulse)
+R=20; // in ohm (resistance of ciicuit)
+L=0.5; // in H (Inductance of circuit)
+V=100; // in V (Battery voltage)
+// calculate
+tou=L/R; // calculation of total time period 
+t=t*1E-6; // changing unit from us to sec
+i=(V/R)*(1-exp(-t/tou)); // calculation of current at t=50 us
+i=i*1E3; // changing unit from A to mA
+printf("\nThe value of current is \t i(50 us) = %.2f mA\n",i);
+if i<I_L then
+    printf("\nSCR will not get fired");
+    
+    else printf("\nSCR will get fired");
+end
\ No newline at end of file
diff --git a/3311/CH2/EX2.10/Ex2_10.sce b/3311/CH2/EX2.10/Ex2_10.sce
new file mode 100755
index 000000000..10c4fcbc3
--- /dev/null
+++ b/3311/CH2/EX2.10/Ex2_10.sce
@@ -0,0 +1,26 @@
+// chapter 2
+// example 2.10
+// Fig. 2.19
+// Compute the value of commutating capacitance and inductance
+// page-54
+clear;
+clc;
+// given
+Edc=50; // in V (source voltage)
+I_L=50; // in A (current)
+t_off=30; // in us (turn-off time of SCR1)
+f=500; // in Hz (chopping frequency)
+neta1=10, neta2=100; // in % (load voltage variation)
+// calculate
+// Let  us assume 50 % tolerance on turn-off time
+t_off=t_off+(50*t_off/100); // calculation of turn-off time for reliable operation
+printf("\nThe turn-off time for reliable operation is \tt_off= %.f us",t_off);
+C=I_L*t_off/Edc; // calculation of commutating capacitance
+printf("\n\nThe commutating capacitance is \t\t\tC= %.f uF",C);
+V0_min=neta1*Edc/100; // calculation of minimum V0
+T=1/f; // calculation of chopping time period
+L1=((V0_min/Edc)^2)*(T^2)/(((%pi)^2)*C*1E-6);
+L1=L1*1E6; // changing unit from H to uH
+ //L1=((V0_min/Edc)^2); // calculation of upper limit of commutating inductance
+L2=C*(Edc/I_L)^2; // calculation of lower limit of commutating inductance
+printf("\n\nThe commutating inductance lies in range \t %.f uH < L < %.f uH",L2,L1);
\ No newline at end of file
diff --git a/3311/CH2/EX2.11/Ex2_11.sce b/3311/CH2/EX2.11/Ex2_11.sce
new file mode 100755
index 000000000..0c51c68a1
--- /dev/null
+++ b/3311/CH2/EX2.11/Ex2_11.sce
@@ -0,0 +1,14 @@
+// chapter 2
+// example 2.11
+// Fig. E2.11
+// Calculate shortest fault clearance time
+// page-54-55
+clear;
+clc;
+// given
+Vm=120; // in V (sinosoidal ac supply)
+integration=15; // in a^2.s (integral of square of current)
+// calculate
+t=integration/Vm^2; // calculation of fault clearance time
+t=t*1E3; // changing unit from s to ms
+printf("\n\nThe fault clearance time is \t= %.2f ms",t);
\ No newline at end of file
diff --git a/3311/CH2/EX2.12/Ex2_12.sce b/3311/CH2/EX2.12/Ex2_12.sce
new file mode 100755
index 000000000..881aefaba
--- /dev/null
+++ b/3311/CH2/EX2.12/Ex2_12.sce
@@ -0,0 +1,17 @@
+// chapter 2
+// example 2.12
+// Calculate one cycle surge current rating
+// page-54-55
+clear;
+clc;
+// given
+I_sub=3000; // in A (half cycle surge current rating)
+f=50; // in Hz (supply frequency)
+T=100, t=50; // time ration for one and half cycle respectively
+// calculate
+// I^2*T=I_sub^2*t, therefore we get
+I=sqrt(I_sub^2*(t/T)); // calculation of one cycle surge current rating
+printf("\nThe one cycle surge current rating \tI= %.2f A",I);
+rating=(I_sub/(5*sqrt(2)))^2*(1/(2*f)); // calculation of i^2*t rating
+printf("\n\nThe i^2*t  rating is \t %.f A^2.s",rating);
+// Note: The answer in the book for i^2*t  rating is wrong due to calculation mistake
\ No newline at end of file
diff --git a/3311/CH2/EX2.2/Ex2_2.sce b/3311/CH2/EX2.2/Ex2_2.sce
new file mode 100755
index 000000000..3bd39215b
--- /dev/null
+++ b/3311/CH2/EX2.2/Ex2_2.sce
@@ -0,0 +1,17 @@
+// chapter 2
+// example 2.2
+// fig. E2.2
+// Obtain the minimum gating pulse
+// page-22
+clear;
+clc;
+// given
+i=4; // in mA (Latching current)
+L=0.1; // in H (Inductance of circuit)
+V=100; // in V (Battery voltage)
+// calculate
+i=i*1E-3; // changing unit from mA to A
+// Since V=L*(di/dt), therefore we get
+t_min=(L/V)*i; // calculation of minimum gating pulse
+t_min=t_min*1E6; // changing unit from sec to us
+printf("\nThe minimum gating pulse is \t t_min=%.f us",t_min);
diff --git a/3311/CH2/EX2.3/Ex2_3.sce b/3311/CH2/EX2.3/Ex2_3.sce
new file mode 100755
index 000000000..81f240984
--- /dev/null
+++ b/3311/CH2/EX2.3/Ex2_3.sce
@@ -0,0 +1,20 @@
+// chapter 2
+// example 2.3
+// fig. E2.3
+// Compute average power loss
+// page-22-23
+clear;
+clc;
+// given
+Beta1=180, Beta2=360; // in degrees (conduction angles)
+Iav=100; // in A (average current)
+// calculate
+// since Iav=Im*Beta/360, therefore
+Im1=Iav*360/Beta1; // calculation of current during 180 conduction
+V_T1= 1.8; // in V (given corresponding to value of Im1)
+Pavg1=V_T1*Im1*(Beta1/360); // calculation of average power loss during 180 conduction
+printf("\nThe average power loss during %.f conduction is %.f W",Beta1,Pavg1);
+Im2=Iav*360/Beta2; // calculation of current during 360 conduction
+V_T2= 1.5; // in V (given corresponding to value of Im2)
+Pavg2=V_T2*Im2*(Beta2/360); // calculation of average power loss during 360 conduction
+printf("\n\nThe average power loss during %.f conduction is %.f W",Beta2,Pavg2);
diff --git a/3311/CH2/EX2.4/Ex2_4.sce b/3311/CH2/EX2.4/Ex2_4.sce
new file mode 100755
index 000000000..d68ebf75b
--- /dev/null
+++ b/3311/CH2/EX2.4/Ex2_4.sce
@@ -0,0 +1,31 @@
+// chapter 2
+// example 2.4
+// Find the value of series resistor and average power
+// page-31
+clear;
+clc;
+// given
+// Vg=1.5+8*Ig; // relation between Vg and Ig
+Vgs=12; // in V
+t=50; // in us
+D=0.2; // duty cucle
+P=5; // in W
+// calculate
+// since Vgs=Ig*Rg+Vg=Ig*Rg+1.5+8*Ig or
+// Vgs=(Rg+8)*Ig+1.5,  (i)
+// since P=Vg*Ig and therefore
+// P=(1.5+8*Ig)*Ig ,
+// P=1.5*Ig+8*Ig^2. 
+// This is quadratic equation and can be written as
+// 8*Ig^2+1.5*Ig-P=0 solving it 
+Ig1=(-1.5+sqrt(1.5^2-(4*8*(-P))))/(2*8);
+Ig2=(-1.5-sqrt(1.5^2-(4*8*(-P))))/(2*8);
+if Ig1>0 then
+    Ig=Ig1
+else
+    Ig=Ig2
+end
+Rg=((Vgs-1.5)/Ig)-8; // calculation of series resistance
+Pavg=P*D; // calculation of average power
+printf("\nThe series resistance is \t Rg=%.f ohm",Rg);
+printf("\nThe average power is \t\t Pavg=%.f W",Pavg);
\ No newline at end of file
diff --git a/3311/CH2/EX2.5/Ex2_5.sce b/3311/CH2/EX2.5/Ex2_5.sce
new file mode 100755
index 000000000..497a07b14
--- /dev/null
+++ b/3311/CH2/EX2.5/Ex2_5.sce
@@ -0,0 +1,21 @@
+// chapter 2
+// example 2.5
+// Calculate the required gate resistance source
+// page-31
+clear;
+clc;
+// given
+Pg=0.012; // in W (power) Pg=Vg*Ig
+gradient=3E3; // gradient=Vg/Ig
+Egs=10; // in V
+// calculate
+// Since gradient*Pg=Vg^2 therefore we get
+Vg=sqrt(gradient*Pg); // calculation of gate voltage
+Ig=Pg/Vg; // calculation of gate current
+Rg=Vg/Ig; // calculation of gate resistance
+Ig=Ig*1E3; // changing unit from A to mA
+Rg=Rg*1E-3; // changing unit from ohm to kohm
+printf("\nThe required gate voltage is \tVg=%.f V\n",Vg);
+printf("\nThe required gate current is \tIg=%.f mA\n",Ig);
+printf("\nThe required gate source resistance is \tRg=%.f kohm\n",Rg);
+// Note:  the value of gate source resistance has not been calculated in the book.
\ No newline at end of file
diff --git a/3311/CH2/EX2.6/Ex2_6.sce b/3311/CH2/EX2.6/Ex2_6.sce
new file mode 100755
index 000000000..f35e9e21f
--- /dev/null
+++ b/3311/CH2/EX2.6/Ex2_6.sce
@@ -0,0 +1,27 @@
+// chapter 2
+// example 2.6
+// Fig. E2.6
+// Calculate the mean power loss
+// page-31-32
+clear;
+clc;
+// given
+// V_T=1.0+(1.1*I/60)  (from graph)
+I_a=23; // in A (steady current)\
+I_b=18; // in A (Half-sine wave)
+I_c=39.6; // in A (level current for half cycle)
+I_d=48.5; // in A (level current for one-third cycle)
+// calculate
+V_T_a=1.0+(1.1*I_a/60); // calculation of ON state voltage corresponding to  I_a
+P_a=V_T_a*I_a; // calculation of power loss corresponding to I_a
+printf("\nThe Power loss is \t%.1f W\n",P_a);
+I_m_b=I_b*%pi; // maximum value of sine wave current
+P_b=(1/(2*%pi))*(integrate('((1+(1.1*I_m_b*sin(x)/60))*I_m_b*sin(x))','x',0,%pi)); // calculation of power loss corresponding to I_b
+printf("\nThe Power loss is \t%.2f W\n",P_b);
+V_T_c=1.0+(1.1*I_c/60); // calculation of ON state voltage corresponding to  I_c
+P_c=V_T_c*I_c/2; // calculation of power loss corresponding to I_c
+printf("\nThe Power loss is \t%.1f W\n",P_c);
+V_T_d=1.0+(1.1*I_d/60); // calculation of ON state voltage corresponding to  I_d
+P_d=V_T_d*I_d/3; // calculation of power loss corresponding to I_d
+printf("\nThe Power loss is \t%.1f W\n",P_d); 
+// Note: the answer of part (b) varies slightly due to precise calculation and round off
\ No newline at end of file
diff --git a/3311/CH2/EX2.7/Ex2_7.sce b/3311/CH2/EX2.7/Ex2_7.sce
new file mode 100755
index 000000000..08a2ede51
--- /dev/null
+++ b/3311/CH2/EX2.7/Ex2_7.sce
@@ -0,0 +1,12 @@
+// chapter 2
+// example 2.7
+// Compute the peak inverse voltage
+// page-32
+clear;
+clc;
+// given
+Vin=415; // in V (input voltage)
+Vf=2.1; // voltage safety factor
+// calculate
+PIV=sqrt(2)*Vin*Vf; // calculation of peak inverse voltage
+printf("\nThe peak inverse voltage is \tPIV=%.2f V",PIV); 
\ No newline at end of file
diff --git a/3311/CH2/EX2.8/Ex2_8.sce b/3311/CH2/EX2.8/Ex2_8.sce
new file mode 100755
index 000000000..2d3b982e3
--- /dev/null
+++ b/3311/CH2/EX2.8/Ex2_8.sce
@@ -0,0 +1,25 @@
+// chapter 2
+// example 2.8
+// Fig. E2.8
+// Calculate the resistance, gate power dissipation and maximum triggering frequency
+// page-32-33
+clear;
+clc;
+// given
+Ig_min=500; // in mA (minimum gate current)
+gradient=16; // in V/A
+Egs=15; // in V (gate source voltage)
+T_on=4; // in us (minimum turn on time)
+Pg_av=0.3; // in W (average gate power dissipation)
+// calculate
+Ig_min=Ig_min*1E-3; // changing unit from mA to A
+Vg=gradient*Ig_min; // calculation of gate voltage
+Rs=(Egs-Vg)/Ig_min; // calculation of resistance
+printf("\nThe resistance to be connected in series with SCR gate is \tRs= %.f ohm",Rs);
+Pg=Vg*Ig_min; // calculation of power dissipation
+printf("\n\nThe gate power dissipation is \t\t\t\t\tPg= %.f W",Pg);
+// Since Pg=Pg_av/(f*T_on), therefore 
+T_on=T_on*1E-6; // changing unit from us to sec
+f=Pg_av/(Pg*T_on); // calculation of maximum triggering frequency
+f=f*1E-3; // changing unit from Hz to khz
+printf("\n\nThe maximum triggering frequency is \tf= %.2f kHz \t or \tF= %.f kHz",f,f);
\ No newline at end of file
diff --git a/3311/CH2/EX2.9/Ex2_9.sce b/3311/CH2/EX2.9/Ex2_9.sce
new file mode 100755
index 000000000..3e801b9fb
--- /dev/null
+++ b/3311/CH2/EX2.9/Ex2_9.sce
@@ -0,0 +1,16 @@
+// chapter 2
+// example 2.9
+// Fig. 2.17
+// Calculate the value of commutating capacitance
+// page-54
+clear;
+clc;
+// given
+Edc=120; // in V (source voltage)
+I=20; // in A (current)
+t_off=60; // in us (turn-off time of both SCR)
+// calculate
+R1=Edc/I; // calculation of R1
+R2=R1; // calculation of R2
+C=1.44*t_off/R1; // calculation of commutating capacitance
+printf("\n\nThe commutating capacitance for succcessful commutation is \tC= %.1f uF",C);
\ No newline at end of file
diff --git a/3311/CH3/EX3.1/Ex3_1.sce b/3311/CH3/EX3.1/Ex3_1.sce
new file mode 100755
index 000000000..e18808278
--- /dev/null
+++ b/3311/CH3/EX3.1/Ex3_1.sce
@@ -0,0 +1,19 @@
+// chapter 3
+// example 3.1
+// fig. E3.11
+// Determine the trigger angle
+// page-87
+clear;
+clc;
+// given
+Ig=0.1; // in mA (minimum gate current)
+Vg=0.5; // in V (minimum gate voltage)
+Emax=24; // in V (peak amplitude of input)
+Rv=100; // in k-ohm
+Rmin=10; // in k-ohm
+Vd=0.7; // in V (threshold voltage for diode)
+// calculate
+e_s=Ig*(Rv+Rmin)+Vd+Vg;  // Applying KVL in the loop
+// since e_s=Emax* sin(alpha)
+alpha=asind(e_s/Emax); // calculation of trigger angle
+printf("The trigger angle is \t %.1f degree",alpha);
\ No newline at end of file
diff --git a/3311/CH3/EX3.2/Ex3_2.sce b/3311/CH3/EX3.2/Ex3_2.sce
new file mode 100755
index 000000000..133156130
--- /dev/null
+++ b/3311/CH3/EX3.2/Ex3_2.sce
@@ -0,0 +1,15 @@
+// chapter 3
+// example 3.2
+// Determine the value of Vee
+// page-99
+clear;
+clc;
+// given
+Re=1; // in k-ohm
+Iv=5; // in mA
+Vv=2; // in V (voltage at valley point)
+// calculate
+Ie=Iv;
+Ve=Vv;
+Vee=Ie*Re+Ve; // calculation of Vee
+printf("The required value to switch OFF UJT is \tVee=%.f V",Vee);
\ No newline at end of file
diff --git a/3311/CH3/EX3.3/Ex3_3.sce b/3311/CH3/EX3.3/Ex3_3.sce
new file mode 100755
index 000000000..ab3dc8225
--- /dev/null
+++ b/3311/CH3/EX3.3/Ex3_3.sce
@@ -0,0 +1,43 @@
+// chapter 3
+// example 3.3
+// Design UJT relaxation oscillator
+// page-99-100
+clear;
+clc;
+// given
+neta=0.7; // (intrinsic stand-off ratio)
+I_P=50; // in uA (peak point curent)
+Vv=2; // in V (valley point voltage)
+I_V=6; // in mA (valley point current)
+V_BB=20; // in V (maximum interbase voltage)
+R_BB=7; // in k-ohm (interbase resistance)
+I_E0=2; // in mA (emitter leakage current)
+Vg_min=0.2 // in V (minimum gate voltage required to trigger SCR)
+C=0.1; // in uF (assumption as done in the book)
+// calculate
+I_P=I_P*1E-6; // changing unit from uA to A
+Rmax=V_BB*(1-neta)/I_P; // calculation of Rmax
+I_V=I_V*1E-3; // changing unit from mA to A
+Rmin=(V_BB-Vv)/I_V; // calculation of Rmin
+R2=1E4/(neta*V_BB);
+I_E0=I_E0*1E-3; // changing unit from mA to A
+R1=Vg_min/I_E0;
+C=C*1E-6; // changing unit from uF to F
+Tmax=Rmax*C*log(1/(1-neta)); // calculation of maximum time period
+Tmin=Rmin*C*log(1/(1-neta)); // calculation of minimum time period
+fmin=1/Tmax; // calculation of minimum frequency
+fmax=1/Tmin; // calculation of maximum frequency
+Rmax=Rmax*1E-3; // changing unit from ohm to k-ohm
+Rmin=Rmin*1E-3; // changing unit from ohm to k-ohm
+Tmax=Tmax*1E3; // changing unit from s to ms
+Tmin=Tmin*1E3; // changing unit from s to ms
+fmax=fmax*1E-3; // changing unit from Hz to kHz
+printf("\nThe maximum value of R is \t\t Rmax=%.f k-ohm",Rmax);
+printf("\nThe minimum value of R is \t\t Rmin=%.f k-ohm",Rmin);
+printf("\nThe value of R2 is \t\t\t R2=%.2f ohm",R2);
+printf("\nThe value of R1 is \t\t\t R1=%.f ohm",R1);
+printf("\nThe maximum value of time period is \t Tmax=%.2f ms",Tmax);
+printf("\nThe minimum value of time period is \t Tmin=%.2f ms",Tmin);
+printf("\nThe minimum value of frequency is \t fmin=%.2f Hz",fmin);
+printf("\nThe minimum value of frequency is \t fmax=%.2f kHz",fmax);
+// Note : the answee of Tmax, fmin, fmax varies slightly due to exact calculation
diff --git a/3311/CH3/EX3.5/Ex3_5.sce b/3311/CH3/EX3.5/Ex3_5.sce
new file mode 100755
index 000000000..00a6c7e35
--- /dev/null
+++ b/3311/CH3/EX3.5/Ex3_5.sce
@@ -0,0 +1,48 @@
+// chapter 3
+// example 3.5
+// Design free-running UJT relaxation oscillator
+// page-105-106
+clear;
+clc;
+// given
+fmin=5; // in Hz (minimum frequency)
+fmax=50; // in Hz (maximum frequency)
+E_dc=12; // in V (DC supply)
+I_P=80; // in mA (peak current)
+T=8; // in us (trigger time)
+V_drop=1; // in V (voltage drop across PUT)
+Rs=39; // in ohm (Assumption as done in the book)
+Ig=1; // in mA (assumption as done in the book
+// calculate
+// since T=Rs*C
+C=T/Rs; // calculation of capacitance (in uF)
+printf("\nThe value of capacitance is \t\t C=%.2f uF",C);
+I_P=I_P*1E-3; // changing unit from mA to A
+V_P=(I_P*Rs)+V_drop; // calculation of peak point voltage
+// since V_P=neta*E_dc+V_D, neglecting V_D, we get
+neta=V_P/E_dc; // calculation of intrinsic stand-off ratio
+Tmax=1/fmin; // calculation of maximum time period
+Tmin=1/fmax; // calculation of maximum time period
+C=C*1E-6; // changing unit from uF to F
+Rmax=Tmax/(C*log(E_dc/(E_dc-V_P))); // calculation of maximum value of R
+Rmin=Tmin/(C*log(E_dc/(E_dc-V_P))); // calculation of minimum value of R
+I_V_max=E_dc/Rmin; // calculation of maximum anode current
+I_V_min=E_dc/Rmax; // calculation of minimum anode current
+// since Ig=2*neta*E_dc/Rg , therefore 
+Rg=2*neta*E_dc/Ig; // calculation of gate resistance in k-ohm
+R1=Rg/neta; // calculation of R1 resistance
+R2=Rg/(1-neta); // calculation of R1 resistance
+Rmax=Rmax*1E-6; // changing unit from ohm to M-ohm
+Rmin=Rmin*1E-6; // changing unit from ohm to M-ohm
+I_V_max=I_V_max*1E6; // changing unit from A to uA
+I_V_min=I_V_min*1E6; // changing unit from A to uA
+printf("\nThe peak point voltage is \t\t V_P=%.2f V",V_P);
+printf("\nThe intrinsic stand-off ratio is \t neta=%.2f",neta);
+printf("\nThe maximum value of R is \t\t Rmax=%.2f M-ohm",Rmax);
+printf("\nThe minimum value of R is \t\t Rmin=%.2f M-ohm",Rmin);
+printf("\nThe maximum value of anode current is \t I_V_max=%.2f uA",I_V_max);
+printf("\nThe minimum value of anode current is \t I_V_min=%.f uA",I_V_min);
+printf("\nThe value of gate resistance is \t Rg=%.2f k-ohm",Rg);
+printf("\nThe value of R1 is \t\t\t R1=%.f k-ohm",R1);
+printf("\nThe value of R2 is \t\t\t Rg=%.2f k-ohm",R2);
+// Note : the answee of Rmax, I_V_max, Rg and R2  varies slightly due to exact calculation
\ No newline at end of file
diff --git a/3311/CH4/EX4.1/Ex4_1.sce b/3311/CH4/EX4.1/Ex4_1.sce
new file mode 100755
index 000000000..40b6dbaac
--- /dev/null
+++ b/3311/CH4/EX4.1/Ex4_1.sce
@@ -0,0 +1,17 @@
+// chapter 4
+// example 4.1
+// Calculate the value of R and C
+// page-120-121
+clear;
+clc;
+// given
+n_s=18; // number of thyristors connected is series
+E_D=500; // in V (maximum permissible blocking voltage)
+E_s=7500; // in V (string voltage)
+dI_b=1; // in mA (range of blocking current)
+dQ=30; // in uC (maximum permissible diffrenece between reverse recovery charge)
+// calculate
+R=(n_s*E_D-E_s)/((n_s-1)*dI_b); // calculation of R in k-ohm
+C=(n_s-1)*dQ/(n_s*E_D-E_s); // calculation of C in uC
+printf("\nThe value of R is \tR=%.2f k-ohm",R);
+printf("\nThe value of C is \tC=%.2f uF",C);
\ No newline at end of file
diff --git a/3311/CH4/EX4.2/Ex4_2.sce b/3311/CH4/EX4.2/Ex4_2.sce
new file mode 100755
index 000000000..e3f67f91b
--- /dev/null
+++ b/3311/CH4/EX4.2/Ex4_2.sce
@@ -0,0 +1,16 @@
+// chapter 4
+// example 4.2
+// Calculate the series resistance
+// page-128-129
+clear;
+clc;
+// given
+I_T1=100; // in A (current of SCR 1)
+I_T2=150; // in A (current of SCR 2)
+V_T1=2.1; // in V (on-state voltage of SCR 1)
+V_T2=1.75; // in V (on-state voltage of SCR 2)
+// calculate
+// since V_T1+I_T1*(R+R_T1)=V_T2+I_T2*(R+R_T2) and assume R+R_T1=R1 (resistance to be connected in series)
+// therefore V_T1+I_T1*R1=V_T2+I_T2*R1 or we get
+R1=(V_T1-V_T2)/(I_T2-I_T1);
+printf("The value of required series resistance is \t R1=%.3f ohm",R1);
diff --git a/3311/CH4/EX4.3/Ex4_3.sce b/3311/CH4/EX4.3/Ex4_3.sce
new file mode 100755
index 000000000..5f065fcff
--- /dev/null
+++ b/3311/CH4/EX4.3/Ex4_3.sce
@@ -0,0 +1,31 @@
+// chapter 4
+// example 4.3
+// Calculate the number of thyristors and value of resistance and capacitance
+// page-130-131
+clear;
+clc;
+// given
+Es=6; // in kV (string voltage)
+Im=4; // in kA (string current)
+E_D=1.2; // in kV (thyristor voltage)
+I_T=1; // in kA (thyristor current)
+neta=90; // in percentage (string efficiency)
+I_B_max=15; // in mA (maximum blockin current)
+dQ_max=25; // in uC (maximum permissible difference between reverse reovery charge)
+// calculate
+neta=neta/100; //changing efficiency from percentage to ratio
+n_s_float=Es/(E_D*neta); // calculation of number of thyristos in series
+n_s= int16(n_s_float)+1; // since n_s will be reduced by decimal value it contaisn if type conversion is done because the decimal part would be removed so we need to add 1 to it
+n_p_float=Im/(I_T*neta); // calculation of number of thyristos in parallel
+n_p= int16(n_p_float)+1; // since n_p will be reduced by decimal value it contaisn if type conversion is done because the decimal part would be removed so we need to add 1 to it
+n_s=double(n_s); // converting again to double for various calculatios 
+n_p=double(n_p); // converting again to double for various calculatios 
+printf("\nThe number of thyristors in series is \t n_s=%.f",n_s);
+printf("\nThe number of thyristors in parallel is  n_p=%.f",n_p);
+E_D=(E_D*1E3); // changing unit from kV to V
+Es=Es*1E3; // changing unit from kV to V
+dI_b=(I_B_max); // (assumption as done in the book)
+R=(n_s*E_D-Es)/((n_s-1)*dI_b); // calculation of resistance in k-ohm
+C=(n_s-1)*dQ_max/(n_s*E_D-Es); // calculation of capacitance in uF
+printf("\nThe value of resistance is \t\t R<=%.f k-ohm",R);
+printf("\nThe value of capacitance is \t\t C>=%.3f uF",C);
diff --git a/3311/CH4/EX4.4/Ex4_4.sce b/3311/CH4/EX4.4/Ex4_4.sce
new file mode 100755
index 000000000..110c274d8
--- /dev/null
+++ b/3311/CH4/EX4.4/Ex4_4.sce
@@ -0,0 +1,23 @@
+// chapter 4
+// example 4.4
+// Calculate the number of thyristors
+// page-132
+clear;
+clc;
+// given
+Es=7.5; // in kV (total applied voltage)
+Im=1000; // in A (total forward current)
+E_D=500; // in V (thyristor voltage)
+I_T=75; // in A (thyristor current)
+neta=14; // in percentage (derating factor)
+// calculate
+Es=Es*1E3; // changing unit from kV to V
+neta=neta/100; //changing efficiency from percentage to ratio
+// since neta=1-(Es/(n_s*E_D)) therefore 
+n_s_float=Es/(E_D*(1-neta)); // calculation of number of thyristos in series
+n_s= int16(n_s_float)+1; // since n_s will be reduced by decimal value it contaisn if type conversion is done because the decimal part would be removed so we need to add 1 to it
+// since neta=1-(Im/(n_s*I_T)) therefore 
+n_p_float=Im/(I_T*(1-neta)); // calculation of number of thyristos in parallel
+n_p= int16(n_p_float)+1; // since n_p will be reduced by decimal value it contaisn if type conversion is done because the decimal part would be removed so we need to add 1 to it
+printf("\nThe number of thyristors in series is \t n_s=%.f",n_s);
+printf("\nThe number of thyristors in parallel is  n_p=%.f",n_p);
\ No newline at end of file
diff --git a/3311/CH4/EX4.5/Ex4_5.sce b/3311/CH4/EX4.5/Ex4_5.sce
new file mode 100755
index 000000000..1191703ef
--- /dev/null
+++ b/3311/CH4/EX4.5/Ex4_5.sce
@@ -0,0 +1,30 @@
+// chapter 4
+// example 4.5
+// Determine the current taken by each SCR and value of equal resistors
+// page-132
+clear;
+clc;
+// given
+// V1=0.9+2.4E-4*I_T1  (voltage characteristics of SCR 1)
+// V2=1.0+2.3E-4*I_T2  (voltage characteristics of SCR 2)
+I1=500, I2=1000, I3=1500, I4=2000; // in A (total current)
+neta=10; // in percentage
+// calculate
+// since SCR are in parallel, therefore V1=V2 or
+// 0.9+2.4E-4*I_T1=1.0+2.3E-4*I_T2. Simplifying this we get
+// 2.4E-4*I_T1-2.3E-4*I_T2=0.1    (i)
+// since I_T1+I_T2=I  (ii)
+// from (i) in (ii), we get
+// 2.4E-4*I_T1-2.3E-4*(I-I_T1)=0.1  or 
+// 4.7E-4*I_T1=0.1+2.3E-4*I  
+// simplifying for I_T1, we get
+// I_T1=(0.1+2.3E-4*I)/4.7E-4
+for I=500:500:2000
+    I_T1=(0.1+2.3E-4*I)/4.7E-4;
+    I_T2=I-I_T1;
+    printf("\n\nFor I=%.f A,\t I_T1=%.f A \t and \t I_T2=%.f A",I,I_T1,I_T2);
+end
+// For 10 % sharing I_T1=1100 A and I_T2=900 A , therefore
+I_T1=1100, I_T2=900; // in A
+R=(0.1+2.3E-4*I-4.7E-4*I_T1)/(I_T1-I_T2);
+printf("\n\nThe value of equal resistors is \t R=%.3f m-ohm",R*1E3);
\ No newline at end of file
diff --git a/3311/CH5/EX5.1/Ex5_1.sce b/3311/CH5/EX5.1/Ex5_1.sce
new file mode 100755
index 000000000..2a7ec7153
--- /dev/null
+++ b/3311/CH5/EX5.1/Ex5_1.sce
@@ -0,0 +1,44 @@
+// chapter 5
+// example 5.1
+// Fig. 5.15
+// What will be the maximum and minimum firing angle 
+// page-155
+clear;
+clc;
+// given
+Vc=40; // in V (breakdown voltage)
+R1_min=1; R1_max=25; // in k-ohm
+C=470; // in nF
+Erms=240; // in V 
+f=50; // in Hz (AC supply frequency)
+// calculate
+C=C*1E-9; // changing unit from nF to F
+R1_min=R1_min*1E3; // changing unit from k-ohm to ohm
+R1_max=R1_max*1E3; // changing unit from k-ohm to ohm
+Zc=1/(2*%pi*f*C); // impedence of capacitor
+phi_min=90-atand(1/(2*%pi*f*R1_min*C));  // calculation of minimum phase angle
+phi_max=90-atand(1/(2*%pi*f*R1_max*C)); // calculation of minimum phase angle
+Zd_min=sqrt(R1_min^2+Zc^2); // calculation of minimum impedence
+Zd_max=sqrt(R1_max^2+Zc^2); // calculation of maximum impedence
+Em=Erms*sqrt(2); // calculation of maximum value of voltage
+Id_min=Em/Zd_max; // 
+Id_max=Em/Zd_min; // calculation of maximum impedence
+Vc_min_peak=Id_min*Zc;
+Vc_max_peak=Id_max*Zc;
+// Now Vc=Vc_max_peak*sin(wt_min+phi_min) and Vc=Vc_min_peak*sin(wt_max+phi_max)
+
+// evaluating both these, we get  wt_min=asind(Vc/Vc_max_peak)+phi_min and wt_max=asind(Vc/Vc_min_peak)+phi_max
+
+wt_min=asind(Vc/Vc_max_peak)+phi_min;
+wt_max=asind(Vc/Vc_min_peak)+phi_max;
+printf("\nThe value of impedence of capacitor is \t\t Zc=%.f ohm",Zc);
+printf("\n\nThe value of minimum phase difference is \t %.1f degree",phi_min);
+printf("\nThe value of maximum phase difference is \t %.2f degree",phi_max);
+printf("\n\nThe value of minimum total impedence is \t Zd_min=%.f ohm",Zd_min);
+printf("\nThe value of maximum total impedence is \t Zd_max=%.f ohm",Zd_max);
+printf("\n\nThe value of minimum peak current is \t\t Id_min=%.3f A",Id_min);
+printf("\nThe value of maximum peak current is \t\t Id_max=%.3f A",Id_max);
+printf("\n\nThe value of minimum peak total voltage is \t Vc_min_peak=%.2f V",Vc_min_peak);
+printf("\nThe value of maximum peak total voltage is \t Vc_max_peak=%.1f V",Vc_max_peak);
+printf("\n\nThe value of minimum delay is \t\t\t =%.2f degree",wt_min);
+printf("\nThe value of maximum delay is \t\t\t =%.1f degree",wt_max);
diff --git a/3311/CH5/EX5.2/Ex5_2.sce b/3311/CH5/EX5.2/Ex5_2.sce
new file mode 100755
index 000000000..c5fdccf7e
--- /dev/null
+++ b/3311/CH5/EX5.2/Ex5_2.sce
@@ -0,0 +1,37 @@
+// chapter 5
+// example 5.2
+// Fig. E5.2
+// Compute the drain current and differnces in current sharing
+// page-174-175
+clear;
+clc;
+// given
+I_T=30; // in A (total current)
+V_DS1=4; // in V (drain to source voltage of MOSFET 1)
+V_DS2=4.5; // in V (drain to source voltage of MOSFET 2)
+R_S1_a=0.4, R_S2_a=0.3; // in ohm (current sharing series resistance for part-a)
+R_S1_b=0.7, R_S2_b=0.7; // in ohm (current sharing series resistance for part-b)
+// calculate
+// Since I_T=I_D1+I_D2 and V_DS1+ID1*R_S1=V_DS2+ID2*R_S2, simplifying both equations for I_D1, we get
+// I_D1=(V_DS2-V_DS1+R_S2*I_T)/(R_S1+R_S2)
+I_D1_a=(V_DS2-V_DS1+R_S2_a*I_T)/(R_S1_a+R_S2_a); // calculation of drain current of MOSFET 1 for part-a
+I_D1_a_percent=I_D1_a*100/I_T; // equivalent value in terms of percentage of total current
+I_D2_a=I_T-I_D1_a; // calculation of drain current of MOSFET 2 for part-a
+I_D2_a_percent=I_D2_a*100/I_T; // equivalent value in terms of percentage of total current
+dI_a=abs(I_D2_a-I_D1_a); // calculation of difference in current for part-a
+dI_a_percent=abs(I_D2_a_percent-I_D1_a_percent); // equivalent value in terms of percentage of total current
+printf("\npart-a\n");
+printf("\nThe drain current of MOSFET 1 is \t I_D1=%.2f A   or   %.2f %%",I_D1_a,I_D1_a_percent);
+printf("\nThe drain current of MOSFET 2 is \t I_D2=%.2f A   or   %.2f %%",I_D2_a,I_D2_a_percent);
+printf("\n\nThe difference in current sharing is \t%.2f A   or   %.2f %%",dI_a,dI_a_percent);
+I_D1_b=(V_DS2-V_DS1+R_S2_b*I_T)/(R_S1_b+R_S2_b); // calculation of drain current of MOSFET 1 for part-a
+I_D1_b_percent=I_D1_b*100/I_T; // equivalent value in terms of percentage of total current
+I_D2_b=I_T-I_D1_b; // calculation of drain current of MOSFET 2 for part-a
+I_D2_b_percent=I_D2_b*100/I_T; // equivalent value in terms of percentage of total current
+dI_b=abs(I_D2_b-I_D1_b); // calculation of difference in current for part-a
+dI_b_percent=abs(I_D2_b_percent-I_D1_b_percent); // equivalent value in terms of percentage of total current
+printf("\n\npart-b\n");
+printf("\nThe drain current of MOSFET 1 is \t I_D1=%.2f A   or   %.1f %%",I_D1_b,I_D1_b_percent);
+printf("\nThe drain current of MOSFET 2 is \t I_D2=%.2f A   or   %.1f %%",I_D2_b,I_D2_b_percent);
+printf("\n\nThe difference in current sharing is \t%.2f A   or   %.1f %%",dI_b,dI_b_percent);
+// Note: the answers for some of the quantity may vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH5/EX5.3/Ex5_3.sce b/3311/CH5/EX5.3/Ex5_3.sce
new file mode 100755
index 000000000..330bdb588
--- /dev/null
+++ b/3311/CH5/EX5.3/Ex5_3.sce
@@ -0,0 +1,31 @@
+// chapter 5
+// example 5.3
+// Determine series resistance and safe highest frequency
+// page-175
+clear;
+clc;
+// given
+I_T=120; // in A (total current)
+C_gs1=2200; // in pF (gate to source capacitance of MOSFET 1)
+C_gd1=390; // in pF (gate to drain capacitance of MOSFET 1)
+L_g1=2; // in nH (stray inductance of MOSFET 1)
+C_gs2=2700; // in pF (gate to source capacitance of MOSFET 2)
+C_gd2=330; // in pF (gate to drain capacitance of MOSFET 2)
+L_g2=2.3; // in nH (stray inductance of MOSFET 2)
+// calculate
+C_gs1=C_gs1*1E-12; // changing unit from pF to F
+C_gd1=C_gd1*1E-12; // changing unit from pF to F
+L_g1=L_g1*1E-9; // changing unit from nF to F
+C_gs2=C_gs2*1E-12; // changing unit from pF to F
+C_gd2=C_gd2*1E-12; // changing unit from pF to F
+L_g2=L_g2*1E-9; // changing unit from nF to F
+f1=1/(2*%pi*sqrt(L_g1*(C_gs1+C_gd1))); // calculation of oscillating frequency of MOSFET 1
+f2=1/(2*%pi*sqrt(L_g2*(C_gs2+C_gd2))); // calculation of oscillating frequency of MOSFET 1
+f_h=min(f1,f2)/10; // calculation of safe highest frequency
+Rg=1/(2*%pi*(C_gs1+C_gd1)*f_h); // calculation of series resistance in the gate
+f_h=f_h*1E-6; // changing unit from Hz to MHz
+printf("\nThe oscillating frequency of MOSFET 1 is \t f1=%.2E Hz",f1);
+printf("\nThe oscillating frequency of MOSFET 2 is \t f2=%.2E Hz",f2);
+printf("\n\n Since the safe highest frequency should be at least 1 decade lower than oscillating frequency, therefore the safe highest frequency is \t %.f MHz",f_h);
+printf("\n\nThe series resistance in the gate terminal of both MOSFET is \t Rg=%.2f ohm",Rg);
+// Note: The answer for the series resistance varies due to precise calculation
\ No newline at end of file
diff --git a/3311/CH5/EX5.4/Ex5_4.sce b/3311/CH5/EX5.4/Ex5_4.sce
new file mode 100755
index 000000000..4a94f80e5
--- /dev/null
+++ b/3311/CH5/EX5.4/Ex5_4.sce
@@ -0,0 +1,17 @@
+// chapter 5
+// example 5.4
+// fig. E5.4
+// Determine the power dissipated by each MOSFET
+// page-175-176
+clear;
+clc;
+// given
+I_T=12; // in A (total current)
+R1=0.2, R2=0.1 // in ohm
+// calculate
+I1=(R2/(R1+R2))*I_T; // applying current divider rule to calculate current through MOSFET 1
+I2=I_T-I1; // calculation of current through MOSFET 2
+P1=I1^2*R1; // calculation of power dissipated by MOSFET 1
+P2=I2^2*R2; // calculation of power dissipated by MOSFET 2
+printf("\nThe power dissipated by MOSFET 1 is \t P1=%.1f W",P1);
+printf("\nThe power dissipated by MOSFET 2 is \t P2=%.1f W",P2);
\ No newline at end of file
diff --git a/3311/CH5/EX5.5/Ex5_5.sce b/3311/CH5/EX5.5/Ex5_5.sce
new file mode 100755
index 000000000..4a4309b41
--- /dev/null
+++ b/3311/CH5/EX5.5/Ex5_5.sce
@@ -0,0 +1,16 @@
+// chapter 5
+// example 5.5
+// Calculate the rise time of driving waveform
+// page-178
+clear;
+clc;
+// given
+C_iss=470; /// in pf (input capacitance)
+Rg=200; // in ohm
+R_L=2.2; // in k-ohm
+// calculate
+C_iss=C_iss*1E-12; // changing unit from pF to F
+// Since Rg=t_r/(2.2*Ciss) therefore 
+t_r=2.2*Rg*C_iss; // calculation of current through MOSFET 2
+t_r=t_r*1E9; // changing unit from s to ns
+printf("\nThe rise time is \t t_r=%.1f ns",t_r);
\ No newline at end of file
diff --git a/3311/CH5/EX5.6/Ex5_6.sce b/3311/CH5/EX5.6/Ex5_6.sce
new file mode 100755
index 000000000..ba871948f
--- /dev/null
+++ b/3311/CH5/EX5.6/Ex5_6.sce
@@ -0,0 +1,26 @@
+// chapter 5
+// example 5.6
+// fig. E 5.6
+// Determine power loss
+// page-182-183
+clear;
+clc;
+// given
+t_r=2; // in us (rise time)
+R_DS_on=0.2; // in ohm (drain to source resistance when MOSFET is ON)
+D=0.7; // duty cycle
+f=30; // in kHz (frequency)
+V_DS=100; // in V (DC power supply)
+R_L=12; // in ohm (load resistance)
+// calculate
+I_D=V_DS/(R_L+R_DS_on); // calculation of drain current
+f=f*1E3; // changing unit from kHz to Hz
+T=1/f; // calculation of switching period
+t_on=D*T; // calculation of  on-time
+W_on=I_D^2*R_DS_on*t_on; // calculation of energy loss during on-time
+P_on=W_on*f; // calculation of power loss during on-time
+printf("\nThe power loss in the on-state is \t\t P_on=%.2f W",P_on);
+t_r=t_r*1E-6; // changing unit from us to s
+W_ON=V_DS*I_D*t_r/6; // calculation of energy loss during turn-on interval
+P_ON=W_ON*f; // calculation of power loss during turn-on interval
+printf("\nThe power loss during the turn-on interval is \t P_ON=%.1f W",P_ON);
\ No newline at end of file
diff --git a/3311/CH5/EX5.7/Ex5_7.sce b/3311/CH5/EX5.7/Ex5_7.sce
new file mode 100755
index 000000000..e6be1ae17
--- /dev/null
+++ b/3311/CH5/EX5.7/Ex5_7.sce
@@ -0,0 +1,29 @@
+// chapter 5
+// example 5.7
+// Calculate the total power loss
+// page-183
+clear;
+clc;
+// given
+V_DS=120; // in V (DC power supply)
+I_D=4; // in A (drain current)
+t_r=80; // in ns (rise time)
+t_f=120; // in ns (fall time)
+I_DSS=2; // in mA (drain current at saturation)
+R_DS_on=0.2; // in ohm (drainn ot source resistance when MOSFET is ON)
+D=50; // in percentage (duty cycle)
+f=45; // in kHz (swithcing frequency)
+// calculate
+f=f*1E3; // changing unit from kHz to Hz
+I_DSS=I_DSS*1E-3; // changing unit from mA to A
+t_r=t_r*1E-9; // changing unit from ns to s
+t_f=t_f*1E-9; // changing unit from ns to s
+T=1/f; // calculation of total period
+t_on=D*T/100; // calculation of on-time
+t_off=(100-D)*T/100; // calculation of on-time
+P_on=I_D^2*R_DS_on*t_on/T; // calculation of on-state power loss
+P_off=V_DS*I_DSS*t_off/T; // calculation of off-state power loss
+Pw_on=(V_DS*I_D*t_r/6)*f; // calculation of turn-on switching power loss
+Pw_off=(V_DS*I_D*t_f/6)*f; // calculation of turn-off switching power loss
+P_T=P_on+P_off+Pw_on+Pw_off; // calculation of total power loss
+printf("\nThe total power loss is \t P_T=%.2f W",P_T);
\ No newline at end of file
diff --git a/3311/CH5/EX5.8/Ex5_8.sce b/3311/CH5/EX5.8/Ex5_8.sce
new file mode 100755
index 000000000..715f122e6
--- /dev/null
+++ b/3311/CH5/EX5.8/Ex5_8.sce
@@ -0,0 +1,29 @@
+// chapter 5
+// example 5.8
+// Fig. E 5.8
+// Determine avg load current and power losses
+// page-201
+clear;
+clc;
+// given
+t_ON=3; // in us (turn-on time)
+t_OFF=1.2; // in us (tunr-off time)
+D=0.7; // duty cycle
+V_CE_sat=2; // in V (collector to emitter voltage at saturation)
+f=1; // in kHz (swithcing frequency)
+R_L=10; // in ohm (load resistance)
+V_CC=200; // in V (collector to emitter volatge)
+// calculate
+t_ON=t_ON*1E-6; // changing unit from us to s
+t_OFF=t_OFF*1E-6; // changing unit from us to s
+f=f*1E3; // changing unit from kHz to Hz
+V_CE_max=V_CC;
+I_C_max=(V_CC-V_CE_sat)/R_L; // calculation of maximum collector(load) current
+I_C_avg=D*I_C_max; // calculation of average collector(load) current
+P_con=V_CE_sat*I_C_avg; // calculation of conduction power loss
+Pw_ON=(V_CE_max*I_C_max*t_ON/6)*f; // calculation of swithcing power loss during turn-on
+Pw_OFF=(V_CE_max*I_C_max*t_OFF/6)*f; // calculation of swithcing power loss during turn-off
+printf("\nThe average load current is \t\t\t I_C_avg=%.2f A",I_C_avg);
+printf("\nThe conduction power loss is \t\t\t %.2f W",P_con);
+printf("\nThe swithcing power loss during turn-on is \t %.2f W",Pw_ON);
+printf("\nThe swithcing power loss during turn-off is \t %.3f W",Pw_OFF);
\ No newline at end of file
diff --git a/3311/CH6/EX6.10/Ex6_10.sce b/3311/CH6/EX6.10/Ex6_10.sce
new file mode 100755
index 000000000..a62a1cc2b
--- /dev/null
+++ b/3311/CH6/EX6.10/Ex6_10.sce
@@ -0,0 +1,25 @@
+// chapter 6
+// example 6.10
+// Determine various parameters
+// page-300-301
+clear;
+clc;
+// given
+E=230; // in V (voltage supply)
+alpha=%pi/6; // in radian (firing angle)
+// calculate
+Em=E*sqrt(2); // calculation of peak output voltage
+Edc=(2*Em/%pi)*cos(alpha); // calculation of average output voltage
+Irms_supply='Id'; // Supply RMS current
+Irms_fundamental='(2*sqrt(2)/%pi)*Id'; // Supply fundamental RMS current
+pf_fundamental=cos(alpha); // calculation of fundamental power factor
+pf_supply=(2*sqrt(2)/%pi)*cos(alpha); // calculation of supply power factor
+hf_supply=sqrt(%pi^2/8-1); // calculation of fundamental harmonic factor
+KV=sqrt(%pi^2/(8*(cos(alpha))^2)-1); // calculation of voltage ripple factor
+printf("\nThe average output voltage is \t\t Edc=%.2f V",Edc);
+printf("\nThe supply RMS current is \t\t Irms_supply=%s",Irms_supply);
+printf("\nThe supply fundamental RMS current is \t Irms_fundamental=%s",Irms_fundamental);
+printf("\nThe fundamental power factor is \t pf_fundamental=%.2f",pf_fundamental);
+printf("\nThe supply power factor is \t\t pf_supply=%.2f",pf_supply);
+printf("\nThe fundamental harmonic factor is \t hf_supply=%.3f",hf_supply);
+printf("\nThe voltage ripple factor is \t\t KV=%.3f",KV);
\ No newline at end of file
diff --git a/3311/CH6/EX6.11/Ex6_11.sce b/3311/CH6/EX6.11/Ex6_11.sce
new file mode 100755
index 000000000..dd1763409
--- /dev/null
+++ b/3311/CH6/EX6.11/Ex6_11.sce
@@ -0,0 +1,26 @@
+// chapter 6
+// example 6.11
+// Find displacement factor, harmonic factor and input power factor
+// page-301
+clear;
+clc;
+// given
+E=120; // in V (voltage supply)
+f=50; // supply frequency
+alpha=%pi/6; // in radian (firing angle)
+// calculate
+DF=cos(-alpha/2); // calculation of displacement factor
+// Since HF=sqrt((Irms/Irms1)^2-1) where Irms=Idc*sqrt(1-(alpha/%pi)) and Irms1=(2*sqrt(2)*Idc/%pi)*cos(alpha/2) 
+//putting both value in formula for HF, we get HF=sqrt((sqrt(1-(alpha/%pi))/((2*sqrt(2)/%pi)*cos(alpha/2)))^2-1)
+HF=sqrt((sqrt(1-(alpha/%pi))/((2*sqrt(2)/%pi)*cos(alpha/2)))^2-1); // calculation of harmonic factor of input current
+// since pf=(Irms1/Irms)*cos(alpha/2) , putting the value of both we get pf=(2*sqrt(2)/%pi)*cos(alpha/2)/(qrt(1-(alpha/%pi)))
+PF=(2*sqrt(2)/%pi)*cos(alpha/2)/(sqrt(1-(alpha/%pi))); // calculation of input power factor
+printf("\nThe displacement factor is \t\t DF=%.4f",DF);
+printf("\nThe harmonic factor of input current is  HF=%.2f percent",HF*100);
+printf("\nThe input power factor is \t\t PF=%.3f ",PF);
+if PF>0 then
+    printf("(lagging)");
+else
+    printf("(leading)");
+end
+// Note: The answer for DF, HF, PF varies slightly due to precise calculation upto 6 decimal digit where as there is 2 decimal digit calculation in the book
\ No newline at end of file
diff --git a/3311/CH6/EX6.12/Ex6_12.sce b/3311/CH6/EX6.12/Ex6_12.sce
new file mode 100755
index 000000000..32411afcd
--- /dev/null
+++ b/3311/CH6/EX6.12/Ex6_12.sce
@@ -0,0 +1,18 @@
+// chapter 6
+// example 6.12
+// Determine average output voltage
+// page-319-320
+clear;
+clc;
+// given
+E=200; // in V (voltage supply per phase)
+alpha1=0, alpha2=30, alpha3=60; // in degree (firing angle)
+V_drop=1.5; // in V (voltage drop across SCR)
+// calculate
+Em=E*sqrt(2); // calculation of peak value of voltage
+Edc1=(3*sqrt(3)/(2*%pi))*Em*cosd(alpha1)-V_drop; // calculation of average load voltage for alpha=0 degree
+Edc2=(3*sqrt(3)/(2*%pi))*Em*cosd(alpha2)-V_drop; // calculation of average load voltage for alpha=30 degree
+Edc3=(3*sqrt(3)/(2*%pi))*Em*cosd(alpha3)-V_drop; // calculation of average load voltage for alpha=60 degree
+printf("\nThe average load voltage for alpha=%.f degree\ is t Edc1=%.2f V",alpha1,Edc1);
+printf("\n\nThe average load voltage for alpha=%.f degree\ is t Edc1=%.2f V",alpha2,Edc2);
+printf("\n\nThe average load voltage for alpha=%.f degree\ is t Edc1=%.2f V",alpha3,Edc3);
diff --git a/3311/CH6/EX6.13/Ex6_13.sce b/3311/CH6/EX6.13/Ex6_13.sce
new file mode 100755
index 000000000..62ee091b7
--- /dev/null
+++ b/3311/CH6/EX6.13/Ex6_13.sce
@@ -0,0 +1,23 @@
+// chapter 6
+// example 6.13
+// Determine average load voltage, current, PIV and power dssipation
+// page-320-321
+clear;
+clc;
+// given
+E_line=380; // in V (voltage line supply)
+I=32; // in A (load-current)
+alpha1=0, alpha2=45; // in degree (firing angle)
+Vt=1.2; // in V (voltage drop across SCR)
+// calculate
+Em=E_line*sqrt(2/3); // calculation of peak value of voltage
+Edc1=(3*sqrt(3)/(2*%pi))*Em*cosd(alpha1)-Vt; // calculation of average load voltage for alpha=0 degree
+Edc2=(3*sqrt(3)/(2*%pi))*Em*cosd(alpha2)-Vt; // calculation of average load voltage for alpha=30 degree
+Irms=I/sqrt(3); // calculation of rms current
+PIV=sqrt(2)*E_line;// calculation of peak inverse voltage
+Pavg=(1/(2*%pi))*(Vt*I)*integrate('1','wt',alpha1,(alpha1+(2*%pi/3)));// calculation of average power dissipation in each thyristor
+printf("\nThe average load voltage for alpha=%.f degree is \t\t Edc1=%.1f V",alpha1,Edc1);
+printf("\nThe average load voltage for alpha=%.f degree is \t Edc1=%.1f V",alpha2,Edc2);
+printf("\nThe rms current is \t\t\t\t\t Irms=%.2f A",Irms);
+printf("\nThe Peak Inverse Voltage is \t\t\t\t PIV=%.1f V",PIV);
+printf("\nThe average power dissipation in each thyristor is \t Pavg=%.1f W",Pavg);
\ No newline at end of file
diff --git a/3311/CH6/EX6.14/Ex6_14.sce b/3311/CH6/EX6.14/Ex6_14.sce
new file mode 100755
index 000000000..a3b94307b
--- /dev/null
+++ b/3311/CH6/EX6.14/Ex6_14.sce
@@ -0,0 +1,23 @@
+// chapter 6
+// example 6.14
+// Calculate thyristor current ratings
+// page-321
+clear;
+clc;
+// given
+E_line=415; // in V (voltage line supply) The value is used  in the solution but not mentioned
+R_L=10; // in ohm
+alpha=30; // in degree (firing angle)
+// calculate
+Em=E_line*sqrt(2/3); // calculation of peak value of voltage
+Edc=(3*sqrt(3)/(2*%pi))*Em*cosd(alpha); // calculation of average load voltage
+Idc=Edc/R_L; // calculation of average load current
+I_T_rms=Idc/sqrt(3); // calculation of thyristor rms current
+I_T_dc=Idc/3; // calculation of thyristor average load current
+I_T_peak=Idc; // calculation of thyristor peak current
+PIV=E_line*sqrt(2); // calculation of thyristor peak inverse voltage
+printf("\nThe average load current \t\t Idc=%.1f A",Idc);
+printf("\nThe thyristor average load current is \t I_T_dc=%.1f A",I_T_dc);
+printf("\nThe thyristor rms current is \t\t I_T_rms=%.1f A",I_T_rms);
+printf("\nThe thyristor peak current is \t\t I_T_peak=%.1f A",I_T_peak);
+printf("\nThe thyristor peak inverse voltage is \t PIV=%.1f V",PIV);
\ No newline at end of file
diff --git a/3311/CH6/EX6.15/Ex6_15.sce b/3311/CH6/EX6.15/Ex6_15.sce
new file mode 100755
index 000000000..8cfe204ee
--- /dev/null
+++ b/3311/CH6/EX6.15/Ex6_15.sce
@@ -0,0 +1,48 @@
+// chapter 6
+// example 6.15
+// Determine various parameters
+// page-322-323
+clear;
+clc;
+// given
+E_L=220; // in V (line voltage)
+f=50; // in Hz (supply frequency)
+R_L=10; // in ohm
+neta=25; // in percent
+// calculate
+Es=E_L/sqrt(3); // calculation of phase voltage
+Em=sqrt(2)*Es; // calculation of peak voltage
+Edc_max=(3*sqrt(3)/(2*%pi))*Em; // calculation of maximum average load voltage
+Edc=(neta/100)*Edc_max; // calculation of average load voltage
+if neta>86.6 then
+    alpha=acosd((2*%pi/(3*sqrt(3)*Em))*Edc);
+else 
+    alpha=acosd((2*%pi/(3*Em))*Edc-1)-30;
+    
+end
+printf("\nThe delay angle \t\t\t %.1f degree",alpha);
+Idc=Edc/R_L; // calculation of average load current
+alpha=alpha*%pi/180; // changing from degree to radian
+Erms=sqrt((Em^2/(2*%pi/3))*integrate('(sin(wt))^2','wt',0.691*%pi,%pi)); // calculation of rms voltage
+Irms=Erms/R_L;// calculation of rms current
+I_T_dc=Idc/3; // calculation of thyristor average load current
+I_T_rms=Irms/sqrt(3); // calculation of thyristor rms current
+Pdc=Idc^2*R_L; // calculation of dc power
+Pac=Irms^2*R_L; // calculation of ac power
+neta=(Pdc/Pac)*100; // calculation of rectification efficiency
+Input_VA=3*Es*I_T_rms; // calculation of input volt-ampere rating
+TUF=(Pdc/Input_VA)*100; // calculation of transformer utilisation factor
+pf=Pac/Input_VA; // calculation of input power factor
+printf("\nThe average output current is \t\t Idc=%.3f A",Idc);
+printf("\nThe rms output current is \t\t Irms=%.2f A",Irms);
+printf("\nThe thyristor average current is \t I_T_dc=%.2f A",I_T_dc);
+printf("\nThe thyristor rms current is \t\t I_T_rms=%.2f A",I_T_rms);
+printf("\nThe rectification efficiency is \t %.2f percent",neta);
+printf("\nThe transformer utilisation factor is \t TUF=%.2f percent",TUF);
+printf("\nThe input power factor is \t\t pf=%.2f",pf);
+if pf>0 then
+    printf(" (lagging)");
+else
+    printf(" (leading)");
+end
+// Note: The answer for Erms, Irms, I_T_rms, neta, TUF, pf vary slightly due to precise calculation
diff --git a/3311/CH6/EX6.17/Ex6_17.sce b/3311/CH6/EX6.17/Ex6_17.sce
new file mode 100755
index 000000000..04892232e
--- /dev/null
+++ b/3311/CH6/EX6.17/Ex6_17.sce
@@ -0,0 +1,34 @@
+// chapter 6
+// example 6.17
+// Calculate firing angle and supply power factor
+// page-341-342
+clear;
+clc;
+// given
+Vs=230; // in V (voltage supply)
+f=50; // supply frequency
+E_batt=200; // in V (battery emf)
+r=0.5; // in ohm (internal resistance of battery)
+Id=20; // in A (load current)
+// calculate
+Edc=E_batt+Id*r; // calculation of battery terminal voltage
+Em=Vs*sqrt(2/3); // calculation of peak voltage
+// Since Edc=(3*sqrt(3)*Em/%pi)*cos(alpha) we get
+alpha=acosd(%pi/(3*sqrt(3)*Em)*Edc); // calculation of firing angle
+Is=sqrt((1/%pi)*Id^2*(2*%pi/3)); // calculation of supply current over one-half cycle
+Idc_rms=Id; // calculation of rms value of output current
+Pd=Edc*Id+Idc_rms^2*r; // calculation of power delivere to the load
+// Since Pd=sqrt(3)*Vs*Is*cos1(alpha1) where cos(alpha1) is supply power factor therefore we get
+pf=Pd/(sqrt(3)*Vs*Is); // calculation of supply power factor
+Edc_batt=E_batt-Id*r; // calculation of dc voltage when battery is delivering power
+// since (-)Edc_batt=(3*sqrt(3)/%pi*Emph*cosd(alpha)) therefore we get
+alpha2=acosd((%pi/(3*sqrt(3)))*(-Edc_batt)/Em); // calculation of firing angle
+printf("\nThe firing angle is \t\t %.2f degree",alpha);
+printf("\nThe supply power factor is \t %.2f",pf);
+if pf>0 then
+    printf(" (lagging)");
+else 
+    printf(" (leading)");
+end
+printf("\n\nWhen battery is delivering the power, the firing angle is \t%.3f degree",alpha2);
+// Note:  The answers for all required values varies slightly due to precise calculation upto 6 digit
\ No newline at end of file
diff --git a/3311/CH6/EX6.19/Ex6_19.sce b/3311/CH6/EX6.19/Ex6_19.sce
new file mode 100755
index 000000000..ea545530b
--- /dev/null
+++ b/3311/CH6/EX6.19/Ex6_19.sce
@@ -0,0 +1,24 @@
+// chapter 6
+// example 6.19
+// Find out SCR rating
+// page-343-344
+clear;
+clc;
+// given
+Es=415; // in V (voltage supply)
+f=50; // supply frequency
+R=100; // in ohm (load resistance)
+alpha=0; // in radian
+// calculate
+Em=Es*sqrt(2/3); // calculation of peak voltage
+Edc=(3*sqrt(3)*Em/%pi)*cos(alpha); // calculation of average voltage
+Idc=Edc/R; // calculation of average output current
+I_T_av=(1/(2*%pi))*Idc*integrate('1','wt',(alpha+%pi/6),(alpha+5*%pi/6)); // calculation of SCR average current
+I_T_rms=sqrt((1/(2*%pi))*Idc^2*integrate('1','wt',(alpha+%pi/6),(alpha+5*%pi/6))); // calculation of SCR rms current
+I_T_peak=Idc; // calculation of SCR peak current
+PIV=sqrt(3)*Em; // calculation of peak inverse voltage of SCR
+printf("\nThe SCR average current is \t I_T_av=%.3f A",I_T_av);
+printf("\nThe SCR rms current is \t\t I_T_rms=%.3f A",I_T_rms);
+printf("\nThe SCR peak current is \t I_T_peak=%.3f A",I_T_peak);
+printf("\n\nThe peak inverse voltage of SCR is \t PIV>=%.f A",PIV);
+// Note: The answers vary slightly due to precise calculations upto 6 decimal digit
\ No newline at end of file
diff --git a/3311/CH6/EX6.2/Ex6_2.sce b/3311/CH6/EX6.2/Ex6_2.sce
new file mode 100755
index 000000000..0c2fa844f
--- /dev/null
+++ b/3311/CH6/EX6.2/Ex6_2.sce
@@ -0,0 +1,23 @@
+// chapter 6
+// example 6.2
+// Determine the heater power
+// page-270
+clear;
+clc;
+// given
+P=1; // in kW (power rating)
+E=230; // in V (voltage rating)
+f=50; // in Hz (supply frequency)
+alpha1=45, alpha2=90; // in degree (delay angle)
+// calculate
+P=P*1E3; // changing unit from kW to W
+Em=E*sqrt(2); // calculation of maximum value of supply voltage
+alpha1_rad=(%pi/180)*alpha1; // changing from degree to radian
+alpha2_rad=(%pi/180)*alpha2; // changing from degree to radian
+Erms1=Em*sqrt(((%pi-alpha1_rad)/(4*%pi))+((sin(2*alpha1_rad))/(8*%pi))); // calculation of rms value of E
+R=E^2/P; // calculation of resistance
+W=Erms1^2/R; // calculation of heater power at 45 degree
+Erms2=Em*sqrt(((%pi-alpha2_rad)/(4*%pi))+((sin(2*alpha2_rad))/(8*%pi))); // calculation of rms value of E
+W2=Erms2^2/R; // calculation of heater power at 45 degree
+printf("\nThe heater power at %.f degree is \t W1=%.2f W",alpha1,W);
+printf("\nThe heater power at %.f degree is \t W2=%.f W",alpha2,W2);
\ No newline at end of file
diff --git a/3311/CH6/EX6.20/Ex6_20.sce b/3311/CH6/EX6.20/Ex6_20.sce
new file mode 100755
index 000000000..c3812283a
--- /dev/null
+++ b/3311/CH6/EX6.20/Ex6_20.sce
@@ -0,0 +1,70 @@
+// chapter 6
+// example 6.20
+// Determine fundamental and various harmonics for various angle
+// page-344-345
+clear;
+clc;
+clf;
+// given
+Es=415; // in V (voltage supply)
+f=50; // supply frequency
+R_L=100; // in ohm (load resistance)
+alpha=0:30:180; // in radian
+n1=1, n5=5, n7=7, n11=11, n13=13;
+// calculate
+Em=Es*sqrt(2/3); // calculation of peak voltage
+printf("\nThe angles are\t\t\t\t")
+for alpha=0:30:180
+    printf("\t%.f\t",alpha);
+
+end
+printf("\nFundamental component of the supply current is");
+for alpha=0:30:180
+    Edc=(3*sqrt(3)*Em/%pi)*cosd(alpha); // calculation of average voltage
+    Idc=Edc/R_L; // calculation of average output current
+    Isn1=abs((2*sqrt(2)*Idc/%pi)*cosd(30*n1)/n1);
+    printf("\t%.3f\t",Isn1);
+
+end
+printf("\n%.fth harmonics component is\t\t",n5);
+for alpha=0:30:180
+    Edc=(3*sqrt(3)*Em/%pi)*cosd(alpha); // calculation of average voltage
+    Idc=Edc/R_L; // calculation of average output current
+    Isn5=abs((2*sqrt(2)*Idc/%pi)*cosd(30*5)/n5);
+    printf("\t%.3f\t",Isn5);
+end
+printf("\n%.fth harmonics component is\t\t",n7);
+for alpha=0:30:180
+    Edc=(3*sqrt(3)*Em/%pi)*cosd(alpha); // calculation of average voltage
+    Idc=Edc/R_L; // calculation of average output current
+    Isn7=abs((2*sqrt(2)*Idc/%pi)*cosd(30*n7)/n7);
+    printf("\t%.3f\t",Isn7);
+end
+printf("\n%.fth harmonics component is\t\t",n11);
+for alpha=0:30:180
+    Edc=(3*sqrt(3)*Em/%pi)*cosd(alpha); // calculation of average voltage
+    Idc=Edc/R_L; // calculation of average output current
+    Isn11=abs((2*sqrt(2)*Idc/%pi)*cosd(30*n11)/n11);
+    printf("\t%.3f\t",Isn11);
+end
+printf("\n%.fth harmonics component is\t\t",n13);
+for alpha=0:30:180
+    Edc=(3*sqrt(3)*Em/%pi)*cosd(alpha); // calculation of average voltage
+    Idc=Edc/R_L; // calculation of average output current
+    Isn13=abs((2*sqrt(2)*Idc/%pi)*cosd(30*n13)/n13);
+    printf("\t%.3f\t",Isn13);
+end
+// plotting
+// since to obtain a smooth graph alpha has been chosen as given below
+alpha=[0:5:180]';
+Edc=(3*sqrt(3)*Em/%pi)*cosd(alpha);
+Idc=Edc/R_L;
+Isn1=abs((2*sqrt(2)*Idc/%pi)*cosd(30*n1)/n1);
+Isn5=abs((2*sqrt(2)*Idc/%pi)*cosd(30*5)/n5);
+Isn7=abs((2*sqrt(2)*Idc/%pi)*cosd(30*n7)/n7);
+Isn11=abs((2*sqrt(2)*Idc/%pi)*cosd(30*n11)/n11);
+Isn13=abs((2*sqrt(2)*Idc/%pi)*cosd(30*n13)/n13);
+plot2d(alpha,[Isn1 Isn5 Isn7 Isn11 Isn13],[1,2,3,4,5],leg="Isn1@Isn5@Isn7@Isn11@Isn11",nax=[2,7,2,10],rect=[0,0,180,5]);
+xlabel("alpha (degrees)");
+title("Fundamental and harmonic current with alpha");
+// Note: The answers vary slightly due to precise calculations upto 6 decimal digit
\ No newline at end of file
diff --git a/3311/CH6/EX6.21/Ex6_21.sce b/3311/CH6/EX6.21/Ex6_21.sce
new file mode 100755
index 000000000..e35e51027
--- /dev/null
+++ b/3311/CH6/EX6.21/Ex6_21.sce
@@ -0,0 +1,31 @@
+// chapter 6
+// example 6.21
+// Determine average voltage
+// page-345
+clear;
+clc;
+clf;
+// given
+Es=415; // in V (voltage supply)
+f=50; // supply frequency
+alpha=[0:30:120]; // in degree
+// calculate
+Em=Es*sqrt(2/3); // calculation of peak voltage
+for alpha=[0:30:120];
+    if alpha<=60 then
+       Edc=(3*sqrt(3)*Em/%pi)*cosd(alpha); // calculation of average voltage for alpha<=60
+   else
+       Edc=(3*sqrt(3)*Em/%pi)*(1+cosd(alpha+60)); // calculation of average voltage for alpha>60
+    end
+    printf("\nFor alpha=%.f,\tEdc=%.1f",alpha,Edc);
+end
+// plot
+alpha=[0:5:60];
+Edc1=(3*sqrt(3)*Em/%pi)*cosd(alpha);
+plot2d(alpha,Edc1);
+alpha=[60:5:120];
+Edc2=(3*sqrt(3)*Em/%pi)*(1+cosd(alpha+60));
+plot2d(alpha,Edc2);
+xlabel("alpha (degrees)");
+ylabel("Edc (avg)  (in V)");
+title("Average output voltage with alpha");
\ No newline at end of file
diff --git a/3311/CH6/EX6.22/Ex6_22.sce b/3311/CH6/EX6.22/Ex6_22.sce
new file mode 100755
index 000000000..9b0f249d5
--- /dev/null
+++ b/3311/CH6/EX6.22/Ex6_22.sce
@@ -0,0 +1,29 @@
+// chapter 6
+// example 6.22
+// Determine the minimum width of gate pulse
+// page-345-346
+clear;
+clc;
+// given
+I_H=0.2; // in A (holding current)
+td=2.5; // in us (delay time)
+wt=%pi/3; // in radian (delay angle)
+L1=8, L2=0; // in mH
+R=2; // in ohm
+E_line=208; // in V (line voltage)
+f=50; // supply frequency
+// calculate
+L1=L1*1E-3;// changing unit from mH to H
+td=td*1E-6;// changing unit from us to s
+Ep=E_line/sqrt(3); // calculation of phase voltage
+Em=Ep*sqrt(2); // calculation of peak voltage
+e=sqrt(3)*Em*sin(wt+%pi/6);
+di_dt_1=e/L1; // calculation of rate of rise of anode current when L=8 mH
+// Since I_H=t1*(di_dt), therefore we get
+t1=I_H/di_dt_1;// calculation of time required for anode current to rise to holding value when L=8 mH
+tp1=t1+td; // calculation of minimum width of gate pulse when L=8 mH
+//di_dt_2=e/L2; // rate of rise of anode current when L=0
+t2=I_H/e*L2;// calculation of time required for anode current to rise to holding value when L=0
+tp2=t2+td; // calculation of minimum width of gate pulse when L=0
+printf("\nThe minimum width of gate pulse when L=8 mH is \t tp1=%.3f us",tp1*1E6);
+printf("\nThe minimum width of gate pulse when L=0 H is \t tp2=%.1f us",tp2*1E6);
\ No newline at end of file
diff --git a/3311/CH6/EX6.23/Ex6_23.sce b/3311/CH6/EX6.23/Ex6_23.sce
new file mode 100755
index 000000000..9d8f1c91d
--- /dev/null
+++ b/3311/CH6/EX6.23/Ex6_23.sce
@@ -0,0 +1,24 @@
+// chapter 6
+// example 6.23
+// Plot average voltage and load voltage
+// page-356-357
+clear;
+clc;
+clf;
+// given
+Es=415; // in V (voltage supply)
+f=50; // supply frequency
+alpha=[0:30:120]; // in degree
+// calculate
+Em=Es*sqrt(2/3); // calculation of peak voltage
+// plot
+alpha=[0:5:60];
+Edc1=(3*sqrt(3)*Em/%pi)*cosd(alpha);
+plot2d(alpha,Edc1);
+alpha=[60:5:120];
+Edc2=(3*sqrt(3)*Em/%pi)*(1+cosd(alpha+60));
+plot2d(alpha,Edc2);
+xlabel("alpha (degrees)");
+ylabel("Edc (avg)  (in V)");
+title("Average output voltage with alpha");
+// since 3-phase waveform can not be plotted, so i have only plotted the average voltage
\ No newline at end of file
diff --git a/3311/CH6/EX6.24/Ex6_24.sce b/3311/CH6/EX6.24/Ex6_24.sce
new file mode 100755
index 000000000..803617f97
--- /dev/null
+++ b/3311/CH6/EX6.24/Ex6_24.sce
@@ -0,0 +1,37 @@
+// chapter 6
+// example 6.24
+// Determine various parameters
+// page-358-359
+clear;
+clc;
+// given
+E_line=220; // in V (line voltage)
+f=50; // supply frequency
+R_L=10; // in ohm
+ratio=25; // in percent (ratio of  given to maximum average output voltage)
+alpha_min=0; // in radian (firing angle for max average output voltage)
+// calculate
+Ep=E_line/sqrt(3); // calculation of phase voltage
+Em=Ep*sqrt(2); // calculation of peak voltage
+Edc_max=(3*sqrt(3)*Em/(2*%pi))*(1+cos(alpha_min)); // calculation of maximum average output voltage
+Edc=(ratio/100)*Edc_max; // calculation of average output voltage
+// since Edc=(3*sqrt(3)*Em/(2*%pi)*(1+cos(alpha));, therefore we get
+alpha=acosd((2*%pi/(3*sqrt(3)*Em))*Edc-1); // calculation of firing angle
+printf("\nThe firing angle is \t\t\t %.f degree",alpha);
+Idc=Edc/R_L; // calculation of average output current
+alpha=alpha*(%pi/180); // changing unit from degree to radian
+Erms=(3*Em/2)*sqrt((%pi-alpha+0.5*sin(2*alpha))/%pi); // calculation of rms voltage
+Irms=Erms/R_L; // calculation of rms current
+I_T_avg=Idc/3; // calculation of SCR average current
+I_T_rms=Irms*sqrt(2)/3; // calculation of SCR rms current
+neta=(Edc*Idc)/(Erms*Irms)*100; // calculation of Rectification efficiency
+Is=Irms*sqrt(2/3);
+Es=3*Ep;
+TUF=(Edc*Idc)/(Es*Is); // calculation of Transformer Utilisation Factor
+printf("\nThe average output current is \t\t Idc=%.2f A",Idc);
+printf("\nThe rms current is \t\t\t Irms=%.2f A",Irms);
+printf("\nThe thyristor average current is \t I_T_avg=%.2f A",I_T_avg);
+printf("\nThe thyristor rms current is \t\t I_T_rms=%.2f A",I_T_rms);
+printf("\nThe Rectification efficiency is \t neta=%.1f percent",neta);
+printf("\nThe Transformer Utilisation Factor is \t TUF=%.3f",TUF);
+// Note : The formula written in the book to calculate Erms and Is is wrong but the answer in the book is according to the correct formula. I have used the correct formula.
\ No newline at end of file
diff --git a/3311/CH6/EX6.25/Ex6_25.sce b/3311/CH6/EX6.25/Ex6_25.sce
new file mode 100755
index 000000000..ad466369b
--- /dev/null
+++ b/3311/CH6/EX6.25/Ex6_25.sce
@@ -0,0 +1,22 @@
+// chapter 6
+// example 6.25
+// Determine DPF, DF, HF and PF
+// page-361
+clear;
+clc;
+// given
+Es=415; // in V (supply voltage)
+f=50; // supply frequency
+alpha=0:30:180; // in degree
+// calculate
+// Since Is_n=(2*sqrt(2)*Idc/%pi)*(cosd(30*n)/n)=0.9*Idc*(cosd(30*n)/n)
+// and Is_fund=0.9*Idc*cosd(30)=0.78*Idc and Is_rms=sqrt(2/3)*Idc,
+// Since DF=Is_fund/Is_rms therefore we get
+DF=(0.78/sqrt(2/3)); // calclation of distortion factor
+HF=sqrt((1/DF)^2-1); // calclation of harmonic factor
+printf("\nangle\t\tDPF\t\tDF\t\tHF\t\tPF");
+for alpha=0:30:180
+    DPF=cosd(alpha); // calclation of displacement power factor
+    SPF=(3/%pi)*cosd(alpha); // calclation of supply power factor
+    printf("\n%.f\t\t%.3f\t\t%.1f %%\t\t%.1f %%\t\t%.3f",alpha,DPF,DF*100,HF*100,SPF);
+end
\ No newline at end of file
diff --git a/3311/CH6/EX6.26/Ex6_26.sce b/3311/CH6/EX6.26/Ex6_26.sce
new file mode 100755
index 000000000..c8b188180
--- /dev/null
+++ b/3311/CH6/EX6.26/Ex6_26.sce
@@ -0,0 +1,21 @@
+// chapter 6
+// example 6.26
+// fig. 6.72
+// Determine overlap angles
+// page-370-371
+clear;
+clc;
+// given
+Em=120; // in V
+f=50; // supply frequency
+L=0.33; // in mH
+Id=4; // in A (load current)
+alpha=15; // in degree (firing angle)
+// calculate
+L=L*1E-3; // changing unit from mH to H
+// since Id=(Em/(2*%pi*f*L))*(1-cosd(u)) therefore we get
+u1=acosd(1-Id*(2*%pi*f*L/Em)); // calclation of overlap angle for case I
+u2=acosd(cosd(alpha)-Id*(2*%pi*f*L/Em))-alpha; // calclation of overlap angle for case II
+printf("\nThe overlap angle for transfer of current from a conducting thyristor to the commutating diode is \t u1=%.3f degree",u1);
+printf("\nThe overlap angle for transfer of current from  the commutating diode to a thyristoris \t\t\t u2=%.3f degree",u2);
+// Note: The answers for u1 and u2 vary slightly due to precise calculation upto 6 decimal digit
\ No newline at end of file
diff --git a/3311/CH6/EX6.27/Ex6_27.sce b/3311/CH6/EX6.27/Ex6_27.sce
new file mode 100755
index 000000000..43c30f657
--- /dev/null
+++ b/3311/CH6/EX6.27/Ex6_27.sce
@@ -0,0 +1,15 @@
+// chapter 6
+// example 6.27
+// fig. Ex. 6.27
+// Find the mean voltage at the load
+// page-371-372
+clear;
+clc;
+// given
+E_line=415; // in V (line voltgae)
+Beta=18; // in degree (advance angle)
+u=3.8; // in degree (overlap angle)
+// calculate
+Em=E_line*sqrt(2/3); // calclation of peak voltage
+Edc=(3*sqrt(3)/(4*%pi))*Em*(cosd(Beta)+cosd(Beta-u)); // calclation of mean voltage at the load
+printf("\nThe mean voltage at the load is \t Edc=%.1f V",Edc);
diff --git a/3311/CH6/EX6.28/Ex6_28.sce b/3311/CH6/EX6.28/Ex6_28.sce
new file mode 100755
index 000000000..8285703d0
--- /dev/null
+++ b/3311/CH6/EX6.28/Ex6_28.sce
@@ -0,0 +1,24 @@
+// chapter 6
+// example 6.28
+// Compute source inductance, load resistance and overlap angle
+// page-371-372
+clear;
+clc;
+// given
+E=400; // in V (supply voltage)
+f=50; // in Hz (supply frequency)
+alpha=%pi/4; // in radian (firing angle)
+Id=10; // in A (load current)
+Edc=360; // in V (load voltage)
+// calculate
+alpha=alpha*(180/%pi);
+disp(alpha);
+Emph=E*sqrt(2/3);// calculation of peak voltage
+// Since Edc=(3*sqrt(3)*Emph/%pi)*cosd(alpha)-(3*2*%pi*f*Ls/%pi)*Id, we get
+Ls=(%pi/(3*2*%pi*f*Id))*((3*sqrt(3)*Emph/%pi)*cosd(alpha)-Edc);// calculation of source inductance
+R=Edc/Id;// calculation of load resistance
+// since Edc=(3*sqrt(3)*Emph/%pi)*cosd(alpha+u)-(3*2*%pi*f*Ls/%pi)*Id, we get
+u=acosd((%pi/(3*sqrt(3)*Emph))*(Edc-(3*2*%pi*f*Ls/%pi)*Id))-alpha;// calculation of overlap angle
+printf("\nThe source inductance is \t Ls=%.1f mH",Ls*1E3);
+printf("\nThe load resistance is \t\t R=%.1f ohm",R);
+printf("\nThe overlap angle is \t\t u=%.f degree",u);
\ No newline at end of file
diff --git a/3311/CH6/EX6.29/Ex6_29.sce b/3311/CH6/EX6.29/Ex6_29.sce
new file mode 100755
index 000000000..3803a6e4e
--- /dev/null
+++ b/3311/CH6/EX6.29/Ex6_29.sce
@@ -0,0 +1,23 @@
+// chapter 6
+// example 6.29
+// Compute the average load voltage
+// page-372-373
+clear;
+clc;
+// given
+Eph=150; // in V (supply voltage per phase)
+f=50; // in Hz (supply frequency)
+Ls=1.2; // in mH (source inductance)
+R=0.07; // in ohm
+V_drop_Thyristor=1.5; // in V (voltage drop across Thyristor)
+Id=30; // in A (continuous load current)
+alpha=0:30:60; // in degree (firing angles)
+// calculate
+Ls=Ls*1E-3; // changing unit from mH to H
+V_drop_reactance=(3*2*%pi*f*Ls/(2*%pi))*Id; // voltage drop due to source reactance
+Em=Eph*sqrt(2);// calculation of peak voltage
+for alpha=0:30:60
+    Edc=((3*sqrt(3)/(2*%pi))*Em*cosd(alpha))-V_drop_Thyristor-V_drop_reactance;;// calculation of average load voltage
+    printf("\nFor %.f degree, the average load voltage is Edc=%.1f V",alpha,Edc);
+end
+// Note: The answers vary slightly due to precise calculation upto 6 decimal digits
\ No newline at end of file
diff --git a/3311/CH6/EX6.3/Ex6_3.sce b/3311/CH6/EX6.3/Ex6_3.sce
new file mode 100755
index 000000000..295e4cbd2
--- /dev/null
+++ b/3311/CH6/EX6.3/Ex6_3.sce
@@ -0,0 +1,28 @@
+// chapter 6
+// example 6.3
+// Determine various parameters
+// page-270-271
+clear;
+clc;
+// given
+E=120; // in V (voltage supply)
+f=50; // in Hz (supply frequency)
+R=10; // in ohm
+neta=25; // in percentage
+// calculate
+Em=E*sqrt(2); // calculation of maximum value of supply voltage
+Edc=(neta/100)*(Em/%pi); // calculation of dc value of voltage
+// since Edc=(Em/(2*%pi))*(1+cos(alpha)) solving for alpha, we get
+alpha=acosd(Edc*(2*%pi/Em)-1); // calculation of firing angle
+Idc=Edc/R; // calculation of average output current
+alpha_rad=(%pi/180)*alpha; // calculation of firing angle in radian
+Erms=Em*sqrt(((%pi-alpha_rad)/(4*%pi))+((sin(2*alpha_rad))/(8*%pi))); // calculation of rms voltage
+Irms=Erms/R; // calculation of rms output current
+Idc_SCR=Idc; // calculation of average SCR current
+Irms_SCR=Irms; // calculation of rms SCR current
+printf("\nThe firing angle is \t%.f",alpha);
+printf("\nThe average output current is \tIdc=%.2f A",Idc);
+printf("\nThe rms output current is \tIrms=%.2f A",Irms);
+printf("\nThe average SCR current is \t%.2f A",Idc_SCR);
+printf("\nThe rms output current is \t%.2f A",Irms_SCR);
+// Note: There is calculation mistake in the book for alpha due to which other values are also coming different.That's why all the answer vary
\ No newline at end of file
diff --git a/3311/CH6/EX6.30/Ex6_30.sce b/3311/CH6/EX6.30/Ex6_30.sce
new file mode 100755
index 000000000..9d67af1b6
--- /dev/null
+++ b/3311/CH6/EX6.30/Ex6_30.sce
@@ -0,0 +1,24 @@
+// chapter 6
+// example 6.30
+// Compute the average generator voltage
+// page-373
+clear;
+clc;
+// given
+E=415; // in V (supply voltage per phase)
+f=50; // in Hz (supply frequency)
+X_L=0.3; // in ohm (source reactance)
+R=0.05; // in ohm (resistance per phase)
+V_drop_Thyristor=1.5; // in V (voltage drop across Thyristor)
+Id=60; // in A (continuous load current)
+Beta=35; // in degree (firing advance angle)
+u=0; // in degree (overlap angle at no load)
+// calculate
+V_drop_reactance=(3*X_L/%pi)*Id; // voltage drop due to overlap
+V_drop_Thyristors=2*V_drop_Thyristor; // voltage drop due to SCRs
+V_drop_resistance=2*R*Id; // voltage drop due to supply resistance
+Emph=E*sqrt(2/3);// calculation of peak voltage
+Edc_noload=-((3*sqrt(3)/%pi)*Emph*cosd(u-Beta));// calculation of average voltage at no load
+Edc=abs(Edc_noload-V_drop_Thyristors-V_drop_reactance-V_drop_resistance);// calculation of average generator voltage
+printf("\nThe average generator voltage is Edc=%.2f V",Edc);
+// Note: The answers vary slightly due to precise calculation upto 6 decimal digits
\ No newline at end of file
diff --git a/3311/CH6/EX6.32/Ex6_32.sce b/3311/CH6/EX6.32/Ex6_32.sce
new file mode 100755
index 000000000..14a3d9a1d
--- /dev/null
+++ b/3311/CH6/EX6.32/Ex6_32.sce
@@ -0,0 +1,24 @@
+// chapter 6
+// example 6.32
+// Compute the firing angle and overlap angle
+// page-373-375
+clear;
+clc;
+// given
+Eph=230; // in V (supply voltage per phase)
+f=50; // in Hz (supply frequency)
+Ls=0.3; // in mH (source inductance)
+Id=15; // in A (load current)
+R=1; // onm (internal resistance)
+E_loadsource=400; // in V (dc source voltage)
+// calculate
+Ls=Ls*1E-3; // changing unit from mH to H
+Edc=E_loadsource+Id*R;// calculation of average voltage
+Emph=Eph*sqrt(2);// calculation of peak voltage
+// Since Edc=(3*sqrt(3)/%pi)*Emph*cosd(alpha)-(3*2*%pi*f*Ls/%pi)*Id, therefore we get
+alpha=acosd((%pi/(3*sqrt(3)*Emph))*(Edc+(3*2*%pi*f*Ls/%pi)*Id));// calculation of firing angle
+// Since Edc=(3*sqrt(3)/%pi)*Emph*cosd(alpha+u)+(3*2*%pi*f*Ls/%pi)*Id, therefore we get
+u=acosd(%pi/(3*sqrt(3)*Emph)*(Edc-(3*2*%pi*f*Ls/%pi)*Id))-alpha;// calculation of overlap angle
+printf("\nThe firing angle is \t%.2f degree",alpha);
+printf("\nThe overlap angle is \t%.3f degree",u);
+// Note: The answers vary slightly due to precise calculation upto 6 decimal digits.In the book, the calculation is done upto 2 decimal digit
\ No newline at end of file
diff --git a/3311/CH6/EX6.33/Ex6_33.sce b/3311/CH6/EX6.33/Ex6_33.sce
new file mode 100755
index 000000000..5767b1af5
--- /dev/null
+++ b/3311/CH6/EX6.33/Ex6_33.sce
@@ -0,0 +1,69 @@
+// chapter 6
+// example 6.33
+// Design the 3-phase bridge convertor
+// page-375-377
+clear;
+clc;
+// given
+E=2.3; // in kV (supply voltage)
+n=10; // delta-star transformer ratio
+f=50; // in Hz (supply frequency)
+Id=90; // in A (load current)
+Edc1=500, Edc2=-500; // in V (range of varying DC voltage)
+Ls=50; // in uH (commutating inductance per phase)
+V_T=1.5; // in V (assumption for voltage drop across SCR as done in the book)
+Tc_max=104; // in degree C (assumption for maximum temperature as done in the book)
+T_A=25; // in degree C (assumption as done in the book)
+theta_CS=0.675; // in dgree C/W (assumption as done in the book)
+Pav=43; // in W (assumption  as done in the book)
+// calculate
+Ls=Ls*1E-6; //changing unit from uH to H
+E=E*1E3; //changing unit from kV to V
+Edc_red=(3*2*%pi*f*Ls/%pi)*Id;// calculation of reduction in output voltage due to overlap
+Edc=Edc1+Edc_red+2*V_T;// calculation of average output voltage
+E_L=(E/n)*sqrt(3);// calculation of line rms voltage
+// Since Edc=1.35*E_L*cosd(alpha), therefore we get
+alpha=acosd(Edc/(1.35*E_L));// calculation of firing angle
+E_DRM=E_L*sqrt(2)*V_T;// calculation of voltage ratings of SCR
+ERRM=E_DRM;// calculation of voltage ratings of SCR
+Iavg=Id/3;// calculation of average output current
+Irms=Id/sqrt(3);// calculation of rms current
+printf("\nThe average output voltage is \t\tEdc=%.2f V",Edc);
+printf("\nThe line rms voltage is \t\tE_L=%.1f V",E_L);
+printf("\nThe firing angle is \t\t\t%.1f degree",alpha);
+printf("\nThe minimum voltgae rating of SCR are \tE_DRM=E_RRM=%.f V",E_DRM);
+printf("\nThe average output current is \t\tIavg=%.f A",Iavg);
+printf("\nThe rms current is \t\t\tIrms=%.2f A",Irms);
+printf("\n\nTherefore we can select SCRs with rating 900 V and 63 A (rms)");
+Edc_2=(Edc2+Edc_red+2*V_T);// calculation of average output voltage in inverting mode. Here minus sign indicates inverting mode
+PF=Edc_2/(1.35*E_L);// calculation of cos(alpha) in inverting mode
+// since cosd(alpha+u)=cosd(alpha)-(2*%pi*f*Ls*Id*sqrt(3/2)/E_L), therefore we get
+alpha_mu=acosd(PF-(2*%pi*f*Ls*Id*sqrt(3/2)/E_L));// calculation of (alpha+mu)
+gama=180-alpha_mu;// calculation of gama
+t_off=gama/(2*%pi*f*(180/%pi));// calculation of off time
+printf("\n\nThe off time is \t t_off=%.3f ms",t_off*1E3);
+theta_CA=(Tc_max-T_A)/Pav;
+// since theta_CA=theta_CS+theta_SA, therefore we get
+theta_SA=theta_CA-theta_CS;
+printf("\n\nThe heat sink parameters is \t theta_SA=%.2f degree C/W", theta_SA);
+Irms_secondary=sqrt(2/3)*Id;// calculation of rms secondary current
+Irms_primary=sqrt(2/3)*Id/n;// calculation of rms primary current
+VA_rating=3*E_L*Irms_secondary/sqrt(3);// calculation of tranformer VA rating
+I_Lf=(3/%pi)*(2*Id/n)*(1/sqrt(2));// calculation of lin rms fundamental current
+I_L=sqrt(2)*Id/n;// calculation of rms current
+printf("\n\nThe rms secondary current is \t\t%.2f A",Irms_secondary);
+printf("\nThe rms primary current is \t\t%.2f A",Irms_primary);
+printf("\nThe tranformer VA rating is \t\t%.1f kVA",VA_rating*1E-3);
+printf("\nThe line rms fundamental current is \tI_Lf=%.2f A",I_Lf);
+printf("\nThe rms current is \t\t\tI_L=%.2f A",I_L);
+DPF=cosd(alpha);// calculation of displacement power factor
+DF=I_Lf/I_L;// calculation of distortion factor
+PF=DPF*DF; // calculation of supply power factor
+Pi=sqrt(3)*E*I_Lf*DPF; // calculation of fundamental input power
+Po=Edc1*Id; // calculation of output power
+neta=(Po/Pi)*100; // calculation of efficiency
+printf("\n\nThe displacement power factor is \tDPF=%.2f",DPF);
+printf("\nThe distortion factor is \t\tDF=%.2f",DF);
+printf("\nThe power factor is \t\t\tPF=%.2f ",PF);
+printf("\nThe efficiency is \t\t\t%.1f percent",neta);
+// Note: The answers vary slightly due to precise calculation upto 6 decimal digits.In the book, the calculation is done upto 2 decimal digit
\ No newline at end of file
diff --git a/3311/CH6/EX6.34/Ex6_34.sce b/3311/CH6/EX6.34/Ex6_34.sce
new file mode 100755
index 000000000..9bfe34299
--- /dev/null
+++ b/3311/CH6/EX6.34/Ex6_34.sce
@@ -0,0 +1,23 @@
+// chapter 6
+// example 6.34
+// Calculate delay angle, power delivered and fundamental reactive power
+// page-377-378
+clear;
+clc;
+// given
+E_line=580; // in V (line to line supply voltage)
+f=50; // in Hz (supply frequency)
+I0=3464; // in A (load current)
+Edc=648; // in V (average output voltage)
+// calculate
+Em=sqrt(2/3)*E_line;
+// since Edc=(3*sqrt(3)/%pi)*Em*cosd(alpha), therefore we get
+alpha=acosd(%pi/(3*sqrt(3)*Em)*Edc);
+Pdc=Edc*I0;
+Pdc=Pdc*1E-3;
+Pac=1.05*Pdc;
+Q_KVAR=sqrt(Pac^2-Pdc^2);
+printf("\nThe delay angle is \t\t\t\t\t\t\t %.2f degree",alpha);
+printf("\nThe power delivered to the load is \t\t\t\t\t Pdc=%.2f kW",Pdc);
+printf("\nThe fundamental reactive power drawn from the supply in KVAR is \t %.2f",Q_KVAR);
+// Note: The answers vary slightly due to precise calculation upto 6 decimal digits.In the book, the calculation is done upto 2 decimal digit
\ No newline at end of file
diff --git a/3311/CH6/EX6.35/Ex6_35.sce b/3311/CH6/EX6.35/Ex6_35.sce
new file mode 100755
index 000000000..cb11af5db
--- /dev/null
+++ b/3311/CH6/EX6.35/Ex6_35.sce
@@ -0,0 +1,22 @@
+// chapter 6
+// exapmle 6.35
+// Calculate reducation in dc output voltage and overlap angle
+// page-378
+clear;
+clc;
+// given
+E_line=400; // in V (line to line supply voltage)
+alpha=30; // in degree (control angle)
+r=15; // in degree (overlap angle)
+alpha_inv_mode=120; // in degree (control angle in inverting mode)
+P=6; // number of pulses
+// calculate
+Emax=sqrt(2/3)*E_line;// calculation of peak voltage
+Edc_with_ovelap=(P/(2*%pi))*Emax*sin(%pi/P)*(cosd(alpha)+cosd(alpha+r));// calculation of average output voltage with overlap
+Edc_without_overlap=(P/%pi)*Emax*(%pi/P)*cosd(alpha);// calculation of average output voltage without overlap
+Edc_drop=Edc_without_overlap-Edc_with_ovelap;// calculation of reducation in dc output voltage
+Beta=180-alpha_inv_mode;// calculation of beta
+r=Beta-acosd((25/(Emax*sin(%pi/P)))-cosd(Beta));// calculation of overlpa angle
+printf("\nThe reducation in dc output voltage due to overlap is \t %.2f V",Edc_drop);
+printf("\nThe overlap angle in the inverting mode is \t\t r= %.f degree",r);
+// Note: The answers vary slightly due to precise calculation upto 6 decimal digits.In the book, the calculation is done upto 2 decimal digit
\ No newline at end of file
diff --git a/3311/CH6/EX6.36/Ex6_36.sce b/3311/CH6/EX6.36/Ex6_36.sce
new file mode 100755
index 000000000..6dc9e62d2
--- /dev/null
+++ b/3311/CH6/EX6.36/Ex6_36.sce
@@ -0,0 +1,79 @@
+// chapter 6
+// example 6.36
+// Calculate various parameters
+// page-393-395
+clear;
+clc;
+// given
+E=230; // in V (supply voltage)
+f=50; // in Hz (supply frequency)
+Ia=10; // in A
+Edc=175; // in V (average output voltage)
+alpha1=33, alpha2=78; // in degree
+Beta1=62; // in degree
+// calculate
+Em=sqrt(2)*E;// calculation of peak voltage
+// EAC control 
+// Since Edc=(Em/%pi)*(1-cosd(Beta)), therefore we get
+Beta=acosd(1-(%pi/Em)*Edc);// calculation of extinction angle
+Is_rms=Ia*sqrt(Beta/180);// calculation of rms supply current
+Is_fund=(2*sqrt(2)*Ia/%pi)*sind(Beta/2);// calculation of rms fundamental current
+DPF=sind(Beta/2);// calculation of displacement factor
+DF=Is_fund/Is_rms;// calculation of distortion factor
+HF=sqrt(1/DF^2-1);// calculation of harmonic factor
+PF=DF*DPF;// calculation of power factor
+printf("\nEAC Control");
+printf("\n\t\tThe extinction angle is \t Beta=%.2f degree",Beta);
+printf("\n\t\tThe rms supply current is \t Is_rms=%.2f A",Is_rms);
+printf("\n\t\tThe rms fundamental current is \t Is_fund=%.2f A",Is_fund);
+printf("\n\t\tThe displacement factor is \t DPF=%.2f",DPF);
+if DPF>=0 then
+    printf(" (lagging)");
+else
+    printf(" (leading)");
+end
+printf("\n\t\tThe distortion factor is \t DF=%.2f percent",DF*100);
+printf("\n\t\tThe harmonic factor is \t\t HF=%.2f percent",HF*100);
+printf("\n\t\tThe power factor is \t\t PF=%.4f",PF);
+if PF>=0 then
+    printf(" (lagging)");
+else
+    printf(" (leading)");
+end
+// SAC control
+// Since Edc=(2*Em/%pi)*cosd(alpha), therefore we get
+alpha=acosd(%pi/(2*Em)*Edc);// calculation of trigger angle
+Is_rms=Ia*sqrt(1-(2*alpha/180));// calculation of rms supply current
+Is_fund=(2*sqrt(2)*Ia/%pi)*cosd(alpha);// calculation of rms fundamental current
+DPF=1;// calculation of displacement factor
+DF=Is_fund/Is_rms;// calculation of distortion factor
+HF=sqrt(1/DF^2-1);// calculation of harmonic factor
+PF=DF*DPF;// calculation of power factor
+printf("\n\nSAC Control");
+printf("\n\t\tThe trigger angle is \t\t alpha=%.2f degree",alpha);
+printf("\n\t\tThe rms supply current is \t Is_rms=%.f A",Is_rms);
+printf("\n\t\tThe rms fundamental current is \t Is_fund=%.1f A",Is_fund);
+printf("\n\t\tThe displacement factor is \t DPF=%.f",DPF);
+printf("\n\t\tThe distortion factor is \t DF=%.f percent",DF*100);
+printf("\n\t\tThe harmonic factor is \t\t HF=%.1f percent",HF*100);
+printf("\n\t\tThe power factor is \t\t PF=%.2f",PF);
+// PWM control
+Beta3=180-alpha1;
+Beta2=180-alpha2;
+alpha3=180-Beta1;
+Edc=(Em/%pi)*(cosd(alpha1)-cosd(Beta1)+cosd(alpha2)-cosd(Beta2)+cosd(alpha3)-cosd(Beta3));// calculation of average output voltage
+Is_rms=(Ia/sqrt(180))*sqrt(Beta1-alpha1+Beta2-alpha2+Beta3-alpha3);// calculation of rms supply current
+Is_fund=(sqrt(2)*Ia/%pi)*(cosd(alpha1)-cosd(Beta1)+cosd(alpha2)-cosd(Beta2)+cosd(alpha3)-cosd(Beta3));// calculation of rms fundamental current
+DPF=1;// calculation of displacement factor
+DF=Is_fund/Is_rms;// calculation of distortion factor
+HF=sqrt(1/DF^2-1);// calculation of harmonic factor
+PF=DF*DPF;// calculation of power factor
+printf("\n\nPWM Control");
+printf("\n\t\tThe average output voltage is \t Edc=%.2f V",Edc);
+printf("\n\t\tThe rms supply current is \t Is_rms=%.2f A",Is_rms);
+printf("\n\t\tThe rms fundamental current is \t Is_fund=%.1f A",Is_fund);
+printf("\n\t\tThe displacement factor is \t DPF=%.f",DPF);
+printf("\n\t\tThe distortion factor is \t DF=%.f percent",DF*100);
+printf("\n\t\tThe harmonic factor is \t\t HF=%.2f percent",HF*100);
+printf("\n\t\tThe power factor is \t\t PF=%.2f",PF);
+// Note: The answers vary slightly due to precise calculation upto 6 decimal digits.In the book, the calculation is done upto 2 decimal digit
\ No newline at end of file
diff --git a/3311/CH6/EX6.4/Ex6_4.sce b/3311/CH6/EX6.4/Ex6_4.sce
new file mode 100755
index 000000000..de8cc6352
--- /dev/null
+++ b/3311/CH6/EX6.4/Ex6_4.sce
@@ -0,0 +1,27 @@
+// chapter 6
+// example 6.4
+// Determine average current, power supplied and dissipated and power factor
+// page-271-272
+clear;
+clc;
+// given
+Erms=230; // in V (voltage supply)
+f=50; // in Hz (supply frequency)
+R=5; // in ohm
+Eb=150; // in V
+// calculate
+Em=Erms*sqrt(2); // calculation of maximum value of supply voltage
+alpha1=asin(Eb/Em); // calculation of firing angle
+Id=(1/(2*%pi*R))*(2*Em*cos(alpha1)-Eb*(%pi-2*alpha1)); // calculation of average charging current
+P_s=Eb*Id; // calculation of power supplied to battery
+Irms=sqrt((1/(2*%pi*R^2))*((Eb^2+Erms^2)*(%pi-2*alpha1)+(Erms^2*sin(2*alpha1))-(4*Em*Eb*cos(alpha1)))); // calculation of rms current
+P_d=Irms^2*R; // calculation of power dissipated in resistor
+pf=(P_d+P_s)/(Erms*Irms); // calculation of supply power factor
+printf("\nThe average charging current is \tId=%.2f A",Id);
+printf("\nThe power supplied to battery is \t%.2f W or \t %.2f kW",P_s,P_s*1E-3);
+printf("\nThe rms current is \tIrms=%.2f A",Irms);
+printf("\nThe power dissipated in resistor is \t%.2f W or \t %.2f kW",P_d,P_d*1E-3);
+printf("\nThe supply power factor is \t%.3f",pf);
+// Note: 1.There is calculation mistake in the book for P_s .
+//       2. The formula used in the book to calculate Irms has little printing error for Em. It should be Erms for the first two Em used
+//       3. The answer slightly vary due to precise calculations
\ No newline at end of file
diff --git a/3311/CH6/EX6.5/Ex6_5.sce b/3311/CH6/EX6.5/Ex6_5.sce
new file mode 100755
index 000000000..20e06231c
--- /dev/null
+++ b/3311/CH6/EX6.5/Ex6_5.sce
@@ -0,0 +1,51 @@
+// chapter 6
+// example 6.5
+// fig. 6.14
+// Determine design details
+// page-287-288
+clear;
+clc;
+// given
+E_supply=230; // in V (voltage supply)
+Im=12; // in A
+Edc=150; // in V
+alpha=30; // in degree
+V_drop=1.5; // in V (voltage drop across SCR)
+// calculate
+// Since Edc=(2*Em/%pi)*cos(alpha)-V_drop, evaluating it for Em we get
+Em=(%pi*(Edc+V_drop))/(2*cosd(alpha)); // calculation of peak voltage
+Erms=Em/sqrt(2); // calculation of rms voltage
+Irms=Im/sqrt(2); // calculation of rms current
+TSR=2*Erms*Irms; // calculation of Transformer secondory rating
+K=E_supply/Erms; // calculation of Transformer voltage ratio
+I_P=Im*(1/K); // calculation of Transformer primary current
+PIV=2*Em;// calculation of PIV for each SCR
+printf("\nFor M-2 connection\n")
+printf("\n\tThe peak voltage is \t\t\tEm=%.1f V",Em);
+printf("\n\tThe rms volatge is \t\t\tErms=%.2f V",Erms);
+printf("\n\tThe rms current is \t\t\tIrms=%.2f A",Irms);
+printf("\n\tThe Transformer secondory rating is \t %.1f kVA",TSR*1E-3);
+printf("\n\tThe Transformer voltage ratio is \tK=%.2f",K);
+printf("\n\tThe Transformer primary current is \tI_P=%.2f A",I_P);
+printf("\n\tThe PIV for each SCR is \t\tPIV=%.f V",PIV);
+Em=(%pi*(Edc+2*V_drop))/(2*cosd(alpha)); // calculation of peak voltage
+Erms=Em/sqrt(2); // calculation of rms voltage
+Irms=Im; // calculation of rms current
+TSR=Erms*Irms; // calculation of Transformer secondory rating
+K=E_supply/Erms; // calculation of Transformer voltage ratio
+I_P=Im*(1/K); // calculation of Transformer primary current
+PIV=Em;// calculation of PIV for each SCR
+I_rms_SCR=Im/sqrt(2); // calculation of rms current for each SCR
+printf("\nFor B-2 connection\n")
+printf("\n\tThe peak voltage is \t\t\tEm=%.2f V",Em);
+printf("\n\tThe rms volatge is \t\t\tErms=%.2f V",Erms);
+printf("\n\tThe rms current is \t\t\tIrms=%.f A",Irms);
+printf("\n\tThe Transformer secondory rating is \t %.2f kVA",TSR*1E-3);
+printf("\n\tThe Transformer voltage ratio is \tK=%.2f",K);
+printf("\n\tThe Transformer primary current is \tI_P=%.2f A",I_P);
+printf("\n\tThe PIV for each SCR is \t\tPIV=%.2f V",PIV);
+printf("\n\tThe rms current for each SCR is \t%.1f A",I_rms_SCR);
+SCR_loss_M2=(V_drop/Edc)*100; // SCR loss in M2 connection
+SCR_loss_B2=(2*V_drop/Edc)*100; // SCR loss in B2 connection
+printf("\n\nThe SCR  loss in M2 connection is \t%.f percent of the load power",SCR_loss_M2);
+printf("\nThe SCR  loss in B2 connection is \t%.f percent of the load power",SCR_loss_B2);
\ No newline at end of file
diff --git a/3311/CH6/EX6.6/Ex6_6.sce b/3311/CH6/EX6.6/Ex6_6.sce
new file mode 100644
index 000000000..2fcdc85c6
--- /dev/null
+++ b/3311/CH6/EX6.6/Ex6_6.sce
@@ -0,0 +1,37 @@
+// chapter 6
+// example 6.6
+// fig. 6.21
+// Determine variuos parameters
+// page-288-290
+clear;
+clc;
+// given
+Erms=230; // in V (voltage supply)
+alpha=%pi/3; // in degree (firing angle)
+Id=4; // in A (load current)
+// calculate
+Em=Erms*sqrt(2); // calculation of rms voltage
+Edc=(2*Em/%pi)*cos(alpha); // calculation of dc output voltage
+Pi=(2*Em/%pi)*Id*cos(alpha); // calculation of active power input
+Qi=(2*Em/%pi)*Id*sin(alpha); // calculation of reactive power input
+R=Edc/Id; // calculation of load resistance
+Edc_1=(Em/%pi)*(1+cos(alpha)); // calculation of dc output voltage when free wheeling diode is connected
+Id_1=Edc_1/R;
+I1=(2*sqrt(2)*Id_1/%pi)*cos(alpha/2); // calculation of fundamental value of alternating current
+Pi_1=(Erms*I1)*cos(alpha/2); // calculation of active input power input when free wheeling diode is connected
+Qi_1=(Erms*I1)*sin(alpha/2); // calculation of reactive power input when free wheeling diode is connected
+Edc_2=Em/(2*%pi)*(1+cos(alpha)); // calculation of dc output voltage when SCR3 is damaged
+Id_2=Edc_2/R; // calculation of dc output current when SCR3 is damaged
+printf("\nThe dc output voltage is \tEdc=%.2f V",Edc);
+printf("\nThe active power input is \tPi=%.2f W",Pi);
+printf("\nThe reactive power input is \tQi=%.2f Vars",Qi);
+printf("\nThe load resistance is \t\tR=%.2f ohm",R);
+printf("\n\nWhen free wheeling diode is connected\n");
+printf("\n\tThe dc output voltage is \tEdc=%.2f V",Edc_1);
+printf("\n\tThe dc output current is \tIdc=%.f V",Id_1);
+printf("\n\tThe fundamental value of alternating current is \tI1=%.2f A",I1);
+printf("\n\tThe active power input is \tPi=%.2f W",Pi_1);
+printf("\n\tThe reactive power input is \tQi=%.f Vars",Qi_1);
+printf("\n\nWhen SCR3 is damaged\n");
+printf("\n\tThe dc output voltage is \tEdc=%.2f V",Edc_2);
+printf("\n\tThe dc output current is \tIdc=%.f A",Id_2);
diff --git a/3311/CH6/EX6.7/Ex6_7.sce b/3311/CH6/EX6.7/Ex6_7.sce
new file mode 100755
index 000000000..5abef4c85
--- /dev/null
+++ b/3311/CH6/EX6.7/Ex6_7.sce
@@ -0,0 +1,20 @@
+// chapter 6
+// example 6.7
+// fig. E6.7
+// Determine the firing angle
+// page-290-291
+clear;
+clc;
+// given
+Erms=220; // in V (voltage supply)
+R=0.5; // in ohm (load resistance)
+Idc=10; // in A (output current)
+Ec_a=135; Ec_b=-145; // in V (capacitor voltage)
+// calculate
+Em=Erms*sqrt(2); // calculation of rms voltage
+Edc_a=Idc*R+Ec_a; // calculation of dc output voltage
+alpha_a=acosd(%pi/(2*Em)*Edc_a); // calculation of firing angle when Vc=135 V
+Edc_b=Idc*R+Ec_b; // calculation of dc output voltage
+alpha_b=acosd(%pi/(2*Em)*Edc_b); // calculation of firing angle when Vc=-145 V
+printf("\nThe firing angle when Ec= %.f V is \t= %.f degree",Ec_a,alpha_a);
+printf("\n\nThe firing angle when Ec= %.f V is \t= %.f degree",Ec_b,alpha_b);
\ No newline at end of file
diff --git a/3311/CH6/EX6.8/Ex6_8.sce b/3311/CH6/EX6.8/Ex6_8.sce
new file mode 100755
index 000000000..d9e86103a
--- /dev/null
+++ b/3311/CH6/EX6.8/Ex6_8.sce
@@ -0,0 +1,31 @@
+// chapter 6
+// example 6.8
+// Determine firing angle, output current and thyristor current
+// page-298-299
+clear;
+clc;
+// given
+E=120; // in V (voltage supply)
+f=50; // supply frequency
+R=10; // in ohm (load resistance)
+neta=25; // in percent
+alpha_min=0; // angle for which average output voltage will be maximum
+// calculate
+Em=E*sqrt(2); // calculation of rms voltage
+Edc_max=(Em/%pi)*(1+cos(alpha_min)); // calculation of maximum average output voltage
+Edc=(neta/100)*Edc_max; // calculation of average output voltage
+// Since Edc=(Em/%pi)*(1+cos(alpha)) , therefore we get
+alpha=acos((%pi/Em)*Edc-1); // calculation of firing angle in radian
+Erms=Em*sqrt(((%pi-alpha)/(2*%pi))+((sin(2*alpha))/(4*%pi))); // calculation of rms load voltage
+Irms=Erms/R; // calculation of rms load current
+Idc=Edc/R; // calculation of average load current
+Im=Em/R; // calculation of maximum thyristor current
+I_TH_avg=(Im/(2*%pi))*(integrate('sin(wt)','wt',alpha,%pi)); // calculation of average thyristor current
+I_TH_rms=sqrt((Im^2/(2*%pi))*(integrate('(sin(wt))^2','wt',alpha,%pi))); // calculation of rms thyristor current
+printf("\nThe firing angle is \t\t\t %.f degree",alpha*(180/%pi));
+printf("\nThe average output voltage is \t\t Edc=%.f V",Edc);
+printf("\nThe rms load voltage is \t\t Erms=%.f V",Erms);
+printf("\nThe average output current is \t\t Idc=%.1f A",Idc);
+printf("\nThe rms load current is \t\t Irms=%.1f A",Irms);
+printf("\nThe average thyristor current is \t I_TH_avg=%.2f A",I_TH_avg);
+printf("\nThe rms thyristor current is \t\t I_TH_rms=%.2f A",I_TH_rms);
diff --git a/3311/CH6/EX6.9/Ex6_9.sce b/3311/CH6/EX6.9/Ex6_9.sce
new file mode 100755
index 000000000..97321961d
--- /dev/null
+++ b/3311/CH6/EX6.9/Ex6_9.sce
@@ -0,0 +1,23 @@
+// chapter 6
+// example 6.9
+// fig. Ex.6.9
+// Find average output current and power delivered
+// page-299-300
+clear;
+clc;
+// given
+E=230; // in V (voltage supply)
+f=50; // supply frequency
+alpha=%pi/4; // in radian (firing angle)
+R=10; // in ohm (load resistance)
+L=10; // in mH 
+Ec=120; // in V (capacitor voltage)
+// calculate
+Em=E*sqrt(2); // calculation of peak voltage
+Edc=(Em/(2*%pi))*(integrate('sin(wt)','wt',alpha,%pi)+abs(integrate('(sin(wt))','wt',%pi,2*%pi))); // The formula used in the book has little mistake
+Idc=(Edc-Ec)/R; // calculation of average output current
+P=Ec*Idc; // calculation of power delivered
+printf("\nThe average output current is \t Idc=%.2f A",Idc);
+printf("\nThe power delivered is \t\t P=%.2f W",P);
+// Note: 1. The integrating formula used in the book has little mistake but the answer is same because they have mistake in calculation. I have used the correct formula 
+//       2. The answers vary slightly due to precise calculation upto 6 decimal digit. In the book, the calculation is upto 2 decimal digit
diff --git a/3311/CH7/EX7.1/Ex7_1.sce b/3311/CH7/EX7.1/Ex7_1.sce
new file mode 100755
index 000000000..d8213c7e9
--- /dev/null
+++ b/3311/CH7/EX7.1/Ex7_1.sce
@@ -0,0 +1,16 @@
+// chapter 7
+// example 7.1
+// Compute the peak value of circulating current
+// page-431
+clear;
+clc;
+// given
+Erms=230; // in V (per phase voltage supply)
+w=315; // in rad/s
+L=12; // in mH
+alpha1=60, alpha2=120; // in degree
+// calculate
+L=L*1E-3; // changing unit from mH to H
+i_cp=(3*sqrt(2)*Erms/(w*L))*(1-cosd(30)); // calculation of peak value of circulating current
+printf("\nThe peak value of circulating current is \t i_cp=%.2f A",i_cp);
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH7/EX7.2/Ex7_2.sce b/3311/CH7/EX7.2/Ex7_2.sce
new file mode 100755
index 000000000..bd50d44a1
--- /dev/null
+++ b/3311/CH7/EX7.2/Ex7_2.sce
@@ -0,0 +1,38 @@
+// chapter 7
+// example 7.2
+// Design dual convertor
+// page-432
+clear;
+clc;
+// given
+Ea=220; // in V
+Ia=30; // in A
+N=1500; // in rpm (speed of motor)
+Eac=400; // in V (3-phase supply)
+f=50; // in Hz (supply frequency)
+drop=15; // in percent (drop in the circuit)
+// calculate
+E_drop=(drop/100)*Ea;// calculation of total drop in the system
+Edc_alpha=Ea+E_drop;// calculation of total dc voltage
+// since Edc_alpha=1.35*Eac*cosd(alpha), therefore we get
+alpha1=acosd(Edc_alpha/(1.35*Eac));// calculation of firing angle
+Iac=0.817*Ia;// calculation of AC line current
+Pac=sqrt(3)*Eac*Iac;// calculation of AC terminal power
+// since Pac=1.35*Pdc, therefore we get
+Pdc=Pac/1.35;// calculation of DC average power
+I_ripple=Ia/5;// calculation of ripple current
+w=2*%pi*f;// calculation of angular velocity
+Lc=(2*1.35*Eac/(6*w*I_ripple))*(1/7+1/5);// calculation of current limiting inductance
+alpha2=180-alpha1;// calculation of firing angle
+PIV=2*sqrt(2)*Eac;// calculation of peak inverse voltage of SCR
+I_T=2*sqrt(2)*Iac;// calculation of current rating of SCR
+printf("\nThe total drop in the system is \t E_drop=%.f V",E_drop);
+printf("\nThe total dc voltage is \t\t Edc_alpha=%.f V",Edc_alpha);
+printf("\nThe firing angle is \t\t\t alpha1=%.f degree",alpha1);
+printf("\nThe AC line current is \t\t\t Iac=%.2f A",Iac);
+printf("\nThe AC terminal power is \t\t Pac=%.2f kW",Pac*1E-3);
+printf("\nThe DC average power is \t\t Pdc=%.2f kW",Pdc*1E-3);
+printf("\nThe current limiting inductance is \t Lc=%.f mH",Lc*1E3);
+printf("\nThe firing angle is \t\t\t alpha2=%.f degree",alpha2);
+printf("\nThe peak inverse voltage of SCR is \t PIV=%.f V",PIV);
+printf("\nThe current rating of SCR is \t\t I_T=%.f A",I_T);
\ No newline at end of file
diff --git a/3311/CH8/EX8.1/Ex8_1.sce b/3311/CH8/EX8.1/Ex8_1.sce
new file mode 100755
index 000000000..03079004a
--- /dev/null
+++ b/3311/CH8/EX8.1/Ex8_1.sce
@@ -0,0 +1,18 @@
+// chapter 8
+// example 8.1
+// Determine time ratio of the chopper
+// page-439
+clear;
+clc;
+// given
+Edc=100; // in V
+L=40; // in mH
+R=5; // in ohm
+I1=10, I2=12; // in A (current limits)
+// calculate
+Iavg=(I1+I2)/2;// calculation of average value of load current
+Imax=Edc/R;// calculation of maximum value of load current
+E0_av=Edc*(Iavg/Imax);// calculation of average value of voltage
+// since Ton/(Ton+Toff)=E0_av/Edc, therefore we get
+Ton_Toff=E0_av/(Edc-E0_av);// calculation of time ratio of the chopper
+printf("\nThe time ratio of the chopper is \t Ton/Toff=%.3f ",Ton_Toff);
\ No newline at end of file
diff --git a/3311/CH8/EX8.10/Ex8_10.sce b/3311/CH8/EX8.10/Ex8_10.sce
new file mode 100755
index 000000000..7106f40ca
--- /dev/null
+++ b/3311/CH8/EX8.10/Ex8_10.sce
@@ -0,0 +1,35 @@
+// chapter 8
+// example 8.10
+// Find the on period, average load current, magnitude of ripple current and its rms value
+// page-464
+clear;
+clc;
+// given
+f=2; // in Khz (chopping frequency)
+Edc=96; // in V (dc source)
+R=8; // in ohm
+tou=6; // in ms (time constant)
+E0=57.6; // in V (average load voltage)
+// calculate
+f=f*1E3; // changing unit from Khz to Hz
+tou=tou*1E-3; // changing unit from ms to s
+T=1/f; // calculation of chopping period
+// Since tou=L/R, therefore we get
+L=tou*R; // calculation of Inductance
+// Since Eo=Edc*(Ton/T), therefore we get
+Ton=(E0/Edc)*T; // calculation of ON period of chopper
+Toff=T-Ton; // calculation of OFF period of chopper
+F_L_rms=Edc*sqrt(Ton/T); // calculation of rms value of load voltage
+I0=E0/R; // calculation of average load current
+del_i=(Edc-E0)*Ton/L; // calculation of current ripple
+I0_max=(Edc/R)*((1-exp(-Ton/tou))/(1-exp(-T/tou))); // calculation of maximum output current
+I0_min=I0_max*exp(-Toff/tou); // calculation of minimum output current
+Ir_rms=(I0_max-I0_min)/(2*sqrt(3)); // calculation of rms value of ripple current
+printf("\nThe ON period of chopper is \t\t Ton=%.1f ms",Ton*1E3);
+printf("\nThe rms value of load voltage is \t %.2f V",F_L_rms);
+printf("\nThe average load current is \t\t I0=%.1f A",I0);
+printf("\nThe magnitude of ripple current is \t %.2f A",del_i);
+printf("\nThe maximum load current is \t\t I0_max=%.2f A",I0_max);
+printf("\nThe minimum load current is \t\t I0_min=%.2f A",I0_min);
+printf("\nThe RMS value of ripple current is \t Ir_rms=%.4f A",Ir_rms);
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.11/Ex8_11.sce b/3311/CH8/EX8.11/Ex8_11.sce
new file mode 100755
index 000000000..ef0e327d1
--- /dev/null
+++ b/3311/CH8/EX8.11/Ex8_11.sce
@@ -0,0 +1,25 @@
+// chapter 8
+// example 8.11
+// Compute the current in the motor
+// page-464-465
+clear;
+clc;
+// given
+Edc=180; // in V (dc source)
+Ra=0.4; // in ohm(armature resistance)
+Eb=80; // in V (back emf)
+i_a=80; // in A(armature current)
+La=8; // in mH (armature inductance)
+t=8; // in ms
+t_off=1; // in ms 
+// calculate
+La=La*1E-3; // changing unit from mH to H
+tou=La/Ra; // calculation of time constant
+t_off=t_off*1E-3; // changing unit from ms to s
+t=t*1E-3; // changing unit from ms to s
+i_t=((Edc-Eb)/Ra)*(1-exp(-t_off/tou))+i_a*exp(-t_off/tou);
+t8=t_off+t; // time instant 8ms after SCR turns off
+i_f=i_t*exp(-t8/tou);
+printf("\nThe current at the instant of Thyristor turns OFF is \t %.3f A",i_t);
+printf("\nThe current %.f ms after Thyristor turns OFF is \t %.2f A",t*1E3,i_f);
+// Note: The value of tou has been calculated wrong in the book due to which answer in the book are wrong
\ No newline at end of file
diff --git a/3311/CH8/EX8.12/Ex8_12.sce b/3311/CH8/EX8.12/Ex8_12.sce
new file mode 100755
index 000000000..c0b4a3973
--- /dev/null
+++ b/3311/CH8/EX8.12/Ex8_12.sce
@@ -0,0 +1,18 @@
+// chapter 8
+// example 8.12
+// Determine the ON time of the chopper
+// page-465
+clear;
+clc;
+// given
+Edc=230; // in V (dc source)
+F=400; // in Hz (chopping frequency)
+E0=150; // in V
+// calculate
+// Siince E0=alpha*Edc, therefore we get,
+alpha=E0/Edc;
+T=1/F;
+// Since alpha=Ton/T, therefore we get,
+Ton=alpha*T;
+printf("\nThe ON time of chopper is \t Ton=%.4f ms",Ton*1E3);
+// Note: The answer varies slightly due to precise calculation upto 6 decimal digit
\ No newline at end of file
diff --git a/3311/CH8/EX8.13/Ex8_13.sce b/3311/CH8/EX8.13/Ex8_13.sce
new file mode 100755
index 000000000..74571f9ea
--- /dev/null
+++ b/3311/CH8/EX8.13/Ex8_13.sce
@@ -0,0 +1,23 @@
+// chapter 8
+// example 8.13
+// Determine average and rms output voltage and form and ripple factor
+// page-465
+clear;
+clc;
+// given
+Edc=220; // in V (dc source)
+Ton=1; // in ms (ON period of chopper)
+Toff=1.5; // in ms (OFF period of chopper)
+// calculate
+T=Ton+Toff; // calculation of chopping period
+alpha=Ton/T; // calculation of duty cycle
+E0=alpha*Edc; // calculation of average output voltage
+E0_rms=sqrt(alpha)*Edc; // calculation of rms output voltage
+FF=E0_rms/E0; // calculation of form factor
+RF=sqrt(FF^2-1); // calculation of ripple factor
+printf("\nThe average output voltage is \t E0=%.f V",E0);
+printf("\nThe rms output voltage is \t E0_rms=%.2f V",E0_rms);
+printf("\nThe form factor is \t\t FF=%.2f ",FF);
+printf("\nThe ripple factor is \t\t RF=%.2f ",RF);
+
+// Note: The answer varies slightly due to precise calculation upto 6 decimal digit
\ No newline at end of file
diff --git a/3311/CH8/EX8.14/Ex8_14.sce b/3311/CH8/EX8.14/Ex8_14.sce
new file mode 100755
index 000000000..231f66bd9
--- /dev/null
+++ b/3311/CH8/EX8.14/Ex8_14.sce
@@ -0,0 +1,25 @@
+// chapter 8
+// example 8.14
+// Determine duty cycle for motoring, regenerating mode and to achieve regenerating mode and poweer returned
+// page-477
+clear;
+clc;
+// given
+Edc=220; // in V (dc source)
+R=0.1; // in ohm
+L=10; // in mH
+Eb=100; // in V (back emf)
+I0=10; // in A
+// calculate
+L=L*1E-3; // changing unit from mH to H
+// since I0=(E0-Eb)/R therefore we get,
+E0=I0*R+Eb; // calculation of average load voltage in motoring mode
+// since E0=alpha*Edc, therefore we get
+alpha_1=E0/Edc; // calculation of duty cycle for motoring mode
+alpha_2=Eb/Edc; // calculation of duty cycle for generating mode
+alpha_3=(Eb-I0*R)/Edc; // calculation of duty cycle to achieve regenerating mode
+P=Eb*I0-I0^2*R; // calculation of power returned to source during braking
+printf("\nThe duty cycle for motoring mode is \t\t %.3f ",alpha_1);
+printf("\nThe critical duty cycle for generating mode is \t %.4f ",alpha_2);
+printf("\nThe duty cycle to achieve regenerating mode is \t %.2f ",alpha_3);
+printf("\nThe power returned to source during braking is \t %.f W",P);
\ No newline at end of file
diff --git a/3311/CH8/EX8.15/Ex8_15.sce b/3311/CH8/EX8.15/Ex8_15.sce
new file mode 100755
index 000000000..7f8931e55
--- /dev/null
+++ b/3311/CH8/EX8.15/Ex8_15.sce
@@ -0,0 +1,31 @@
+// chapter 8
+// example 8.14
+// Determine duty cycle for motoring, regenerating mode and to achieve regenerating mode, poweer returned and switching frequency
+// page-478
+clear;
+clc;
+// given
+Edc=220; // in V (dc source)
+R=0.1; // in ohm
+L=10; // in mH
+Eb=100; // in V (back emf)
+I0=10; // in A
+f=5; // in KHz (output frequency)
+// calculate
+L=L*1E-3; // changing unit from mH to H
+// since I0=(E0-Eb)/R therefore we get,
+E0_m=I0*R+Eb; // calculation of average load voltage in motoring mode
+// since E0=(2*alpha-1)*Edc, therefore we get
+alpha_m=(E0_m/Edc+1)/2; // calculation of duty cycle for motoring mode
+alpha_c=1-alpha_m; // calculation of duty cycle for generating mode
+// since I0=(Eb-E0)/R  during regeneration mode, therefore we get
+E0_r=Eb-I0*R;
+// since E0=-(2*alpha_r-1)*Edc
+alpha_r=(1-E0_r/Edc)/2;
+P=Eb*I0-I0^2*R; // calculation of power returned to source during braking
+f_s=f/2;
+printf("\nThe duty cycle for motoring mode is \t\t alpha_m=%.2f ",alpha_m);
+printf("\nThe critical duty cycle for generating mode is \t alpha_c=%.2f ",alpha_c);
+printf("\nThe duty cycle to achieve regenerating mode is \t alpha_r=%.3f ",alpha_r);
+printf("\nThe power returned to source during braking is \t P=%.f W",P);
+printf("\nThe switching frequency of the device is \t fs=%.1f KHz",f_s);
diff --git a/3311/CH8/EX8.16/Ex8_16.sce b/3311/CH8/EX8.16/Ex8_16.sce
new file mode 100755
index 000000000..d67c5c66f
--- /dev/null
+++ b/3311/CH8/EX8.16/Ex8_16.sce
@@ -0,0 +1,33 @@
+// chapter 8
+// example 8.16
+// Determine duty cycle of chopper
+// page-480
+clear;
+clc;
+// given
+Edc=200; // in V (dc source)
+R=0.1; // in ohm
+L=10; // in mH
+Eb1=150, Eb2=-110; // in V (back emf)
+I0=10; // in A
+// calculate
+L=L*1E-3; // changing unit from mH to H
+// since I0=(E0-Eb)/R therefore we get,
+E01=I0*R+Eb1; // calculation of average load voltage when Eb=150 V
+E02=I0*R+Eb2; // calculation of average load voltage when Eb=-110 V
+// since E0=2*Edc(alpha-0.5), therefore we get
+alpha1=(E01/(2*Edc))+0.5; // calculation of duty cycle when Eb=150 V
+alpha2=(E02/(2*Edc))+0.5; // calculation of duty cycle when Eb=-110 V
+printf("\nThe duty cycle when Eb=%.f V is \t %.3f ",Eb1,alpha1);
+if alpha1>0.5 then
+    printf("\t\t It is forwarding mode");
+else
+    printf("\t\t It is reversing motoring mode");
+end
+printf("\nThe duty cycle when Eb=%.f V is \t %.3f ",Eb2,alpha2);
+if alpha2>0.5 then
+    printf("\t\t It is forwarding mode");
+else
+    printf("\t\t It is reversing motoring mode");
+end
+// Note : the answer vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.17/Ex8_17.sce b/3311/CH8/EX8.17/Ex8_17.sce
new file mode 100755
index 000000000..d62d90c60
--- /dev/null
+++ b/3311/CH8/EX8.17/Ex8_17.sce
@@ -0,0 +1,22 @@
+// chapter 8
+// example 8.17
+// fig. 8.26
+// Compute the value of commutating capacitor and inductor
+// page-483-484
+clear;
+clc;
+// given
+Edc=80; // in V (dc source)
+Toff=20; // in us (turn off time of SCR)
+T=2000; // in us (chopping period)
+I0_m=80; // in A (starting current)
+// calculate
+Toff=Toff*1E-6;
+T=T*1E-6;
+dt=Toff; // assumption as done in the book
+t_q=Toff+dt;
+C=I0_m*(t_q)/Edc; // calculation of commutating capacitance
+L_min=C*(Edc/I0_m); // calculation of minimum commutating inductance
+L_max=0.01*T^2/(%pi^2*C); // calculation of maximum commutating inductance
+printf("\nThe commutating capacitance is \t C=%.f uF",C*1E6);
+printf("\nThe commutating inductance lies in the range \t %.f uH <= L <= %.2f uH",L_min*1E6,L_max*1E6);
\ No newline at end of file
diff --git a/3311/CH8/EX8.18/Ex8_18.sce b/3311/CH8/EX8.18/Ex8_18.sce
new file mode 100755
index 000000000..9a6de5ad8
--- /dev/null
+++ b/3311/CH8/EX8.18/Ex8_18.sce
@@ -0,0 +1,24 @@
+// chapter 8
+// example 8.18
+// Compute the value of commutating capacitor and inductor, Maximum capacitor voltage, and peak commutating current
+// page-491
+clear;
+clc;
+// given
+Edc=220; // in V (dc source)
+Toff=20; // in us (turn off time of SCR)
+I0_m=180; // in A (starting current)
+x=3
+// calculate
+Toff=Toff*1E-6;
+dt=Toff; // assumption as done in the book
+t_q=Toff+dt;
+L=(Edc*t_q)/(x*I0_m*(%pi-2*asin(1/x))); // calculation of commutating inductance
+C=x*I0_m*t_q/(Edc*(%pi-2*asin(1/x))); // calculation of commutating capacitance
+V_cp=Edc+I0_m*sqrt(L/C); // calculation of Maximum capacitor voltage
+i_cp=x*I0_m; // calculation of peak commutating current
+printf("\nThe commutating inductance is \t\t L=%.2f uH",L*1E6);
+printf("\nThe commutating capacitance is \t\t C=%.2f uF",C*1E6);
+printf("\nThe maximum capacitor voltage is \t V_cp=%.2f V",V_cp);
+printf("\nThe peak commutating current is \t i_cp=%.f A",i_cp);
+// Note: the answer for i_cp is wrong in the book due to use of wrong value in the calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.19/Ex8_19.sce b/3311/CH8/EX8.19/Ex8_19.sce
new file mode 100755
index 000000000..668992a0e
--- /dev/null
+++ b/3311/CH8/EX8.19/Ex8_19.sce
@@ -0,0 +1,24 @@
+// chapter 8
+// example 8.19
+// Compute the value of commutating capacitance, average output voltage, circuit off-time, total commutation interval
+// page-495
+clear;
+clc;
+// given
+Edc=230; // in V (dc source)
+I0=50; // in A (load current)
+alpha=0.4; // duty cycle
+f=2; // in KHz (chopping frequency)
+// calculate
+f=f*1E3;// changing unit from KHz to Hz
+T=1/f; // calculation of chopping period
+// since alpha=Ton/T, therefore we get
+Ton=alpha*T; // calculation of ON period of chopper
+C=Ton*I0/(2*Edc); // calculation of commutating capacitance
+E0=2*Edc^2*C*f/I0; // calculation of average output voltage
+t_q=Ton/2; // calculation of circuit off-time
+T_interval=2*C*Edc/I0; // calculation of total commutation interval
+printf("\nThe commutating capacitance is \t\t\t C=%.2f uF",C*1E6);
+printf("\nThe average output voltage is \t\t\t E0=%.f V",E0);
+printf("\nThe circuit tunr-off time for one SCR pair is \t t_q=%.f us",t_q*1E6);
+printf("\nThe total commutation interval is \t\t %.f us",T_interval*1E6);
\ No newline at end of file
diff --git a/3311/CH8/EX8.20/Ex8_20.sce b/3311/CH8/EX8.20/Ex8_20.sce
new file mode 100755
index 000000000..f91c503c3
--- /dev/null
+++ b/3311/CH8/EX8.20/Ex8_20.sce
@@ -0,0 +1,22 @@
+// chapter 8
+// example 8.20
+// Compute the value of commutating capacitance and transformer inductances
+// page-499
+clear;
+clc;
+// given
+Edc=60; // in V (dc source)
+I0_m=140; // in A (load current)
+t_q=20; // in us
+g=4;
+// calculate
+t_q=t_q*1E-6; // changing unit from us to s
+Rm=Edc/I0_m;
+// since g=(1/Rm)*sqrt(L1/C) and t_q=sqrt(L1*C),
+// Multiplying both these equations we get g*t_q=(1/Rm)*L1 or we get
+L1=g*t_q*Rm; // calculation of transformer inductance L1
+C=t_q^2/L1; // calculation of commutating capacitance
+L2=L1; // calculation of transformer inductance L2
+printf("\nThe commutating capacitance is \t C=%.2f uF",C*1E6);
+printf("\nThe transformer inductances is \t L1=%.1f uH \t L2=%.1f uH",L1*1E6, L2*1E6);
+// Note: the answers vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.21/Ex8_21.sce b/3311/CH8/EX8.21/Ex8_21.sce
new file mode 100755
index 000000000..2b44ce4bc
--- /dev/null
+++ b/3311/CH8/EX8.21/Ex8_21.sce
@@ -0,0 +1,35 @@
+// chapter 8
+// example 8.21
+// fig. 8.32
+// Compute the inductance, steady-state speed and current swing
+// page-499-500
+clear;
+clc;
+// given
+di_a=6; // in A
+n=1750; // in rpm (rated speed of motor)
+HP=150; // in HP (horse power rating)
+Ra=0.0099; // in ohm (armature resistance)
+Eff=90; // in percent
+Ea=1200; // in V (armature voltage)
+Edc=Ea;
+T=2500; // in us (chopping period)
+alpha=0.10; // duty cycle
+L1=125; // in mH
+// calculate
+T=T*1E-6; // changing unit from us to s
+// since dIa/d(alpha)=(Edc/L)*T*(1-2*alpha), and dIa/d(alpha)=0 therefore we get
+// 1-2*alpha_worst=0
+alpha_worst=1/2; // calculation of duty cycle for worst case of motor
+// since di_a=(Edc-alpha_worst*Edc)/L, therefore we get
+L=(Edc-alpha_worst*Edc)/di_a*alpha_worst*T; // calculation of inductance
+Pin=HP*746/(Eff/100); // calculation of power input to the motor
+Ia=Pin/Edc; // calculation of rated current in the armature
+Ea_rated=Edc-Ia*Ra; // calculation of armature voltage under rated torque
+Va=alpha*Edc-Ia*Ra; // calculation of voltage at the armature
+N=(Va/Ea_rated)*n; // calculation of steady-state speed
+del_i_a=(Edc-alpha*Edc)/L*alpha*T; // calculation of current swing
+printf("\nThe inductance is \t\t L=%.f mH",L*1E3);
+printf("\nThe steady-state speed is \t N=%.2f rpm",N);
+printf("\nThe current swing is \t\t del_i_a=%.2f A",del_i_a);
+// Note: the answers vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.22/Ex8_22.sce b/3311/CH8/EX8.22/Ex8_22.sce
new file mode 100755
index 000000000..2c8585cb7
--- /dev/null
+++ b/3311/CH8/EX8.22/Ex8_22.sce
@@ -0,0 +1,38 @@
+// chapter 8
+// example 8.22
+// Design the jones chopper
+// page-500-501
+clear;
+clc;
+// given
+Edc=200; // in V (source voltage)
+I0=50; // in A (load current)
+t_q=200; // in us
+safety_factor=1.5;
+// calculate
+t_q=t_q*1E-6;  // changing unit from us to s
+C=(%pi/2)*(t_q/Edc)*I0; // calculation of commutating capacitance
+V_C=safety_factor*Edc; // calculation of capacitor voltage rating
+// since t_q=sqrt(L1*C), therefore we get
+L1=t_q^2/C; // calculation of commutating inductance L1
+L2=L1; // calculation of commutating inductance L2
+V_BO=safety_factor*Edc; // for SCR 1
+I_T=safety_factor*I0; // for SCR 1
+t_q2=(%pi/2)*sqrt(L1*C); // for SCR 1
+PIV=V_BO; // calculation of Peak inverse voltage for diode D1
+I_D=I_T; // calculation of diode current for diode D1
+dV_dt_1=I0/C; // dynamic characteristics for SCR 1
+di_dt_1=safety_factor*Edc/L1; // dynamic characteristics for SCR 1
+E_peak=safety_factor*Edc;
+dV_dt_2=E_peak/sqrt(L1*C); // dynamic characteristics for SCR 2
+L=2; // in uH (assumption as done in the book)
+di_dt_2=E_peak/L; // dynamic characteristics for SCR 2
+printf("\nThe commutating capacitance is \t\t C=%.2f uF",C*1E6);
+printf("\n\nThe capacitor voltage rating is \t V_C=%.f V",V_C);
+printf("\n\nThe commutating inductances are \t L1=%.2f mH \t or L2=%.2f mH",L1*1E3,L2*1E3);
+printf("\n\nThe characteristics of SCR1 are \t V_BO=%.f V \t I_T=%.f A",V_BO,I_T);
+printf("\n\nThe characteristics of SCR2 are \t t_q<=%.f us or t_q=250 us \t V_BO=%.f V \t I_T=%.f A",t_q2*1E6,V_BO,I_T);
+printf("\n\nThe characteistics of diode D1 are \t PIV=%.f V \t I_D=%.f A",V_BO,I_D);
+printf("\n\nThe dynamic characteistics of SCR1 are \t dV/dt=%.2f V/us \t di/dt=%.2f A/us",dV_dt_1*1E-6,di_dt_1*1E-6);
+printf("\n\nThe dynamic characteistics of SCR2 are \t dV/dt=%.2f V/us \t di/dt=%.f A/us",dV_dt_2*1E-6,di_dt_2*1E-6);
+// Note: the answers vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.23/Ex8_23.sce b/3311/CH8/EX8.23/Ex8_23.sce
new file mode 100755
index 000000000..bf53d8efc
--- /dev/null
+++ b/3311/CH8/EX8.23/Ex8_23.sce
@@ -0,0 +1,24 @@
+// chapter 8
+// example 8.23
+// fig 8.43
+// Find duty cycle, filter inductance and filter capacitance
+// page-514-515
+clear;
+clc;
+// given
+Edc=14; // in V (dc source)
+E0=6; // in V (average output voltage)
+del_Vc=15; // mV (peak to peak ripple voltage)
+del_I=0.6; // in A (peak to peak ripple current)
+f=30; // in KHz (switching frequency)
+// calculate
+del_Vc=del_Vc*1E-3; // changing unit from mV to V
+f=f*1E3; // changing unit from KHz to Hz
+alpha=E0/Edc; // calculation of duty cycle
+L=E0*(Edc-E0)/(f*Edc*del_I); // calculation of filter inductance
+C=del_I/(8*f*del_Vc); // calculation of filter capacitance
+
+printf("\nThe duty cycle is \t\t alpha=%.4f \t or %.2f percent",alpha,alpha*100);
+printf("\nThe filter inductance is \t L=%.2f uH",L*1E6);
+printf("\nThe filter capacitance is \t C=%.2f uF",C*1E6);
+// Note: the answers vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.24/Ex8_24.sce b/3311/CH8/EX8.24/Ex8_24.sce
new file mode 100755
index 000000000..2749836b0
--- /dev/null
+++ b/3311/CH8/EX8.24/Ex8_24.sce
@@ -0,0 +1,28 @@
+// chapter 8
+// example 8.24
+// Determine maximum ON-period of MOSFET, Battery drain current and the value of choke required
+// page-515
+clear;
+clc;
+// given
+Edc=12; // in V
+Edc_max=13.5; // in V (maximum dc source)
+Edc_min=10; // in V (minimum dc source)
+E0=5; // in V (average output voltage)
+I0=10; // in A (load current)
+f=50; // in KHz 
+del_I=500; // in mA (ripple current)
+// calculate
+f=f*1E3; // changing unit from KHz to Hz
+del_I=del_I*1E-3; // changing unit from mA to A
+T=1/f; // calculation of time period
+alpha_max=E0/Edc_min; // calculation of duty cycle
+// since alpha=Ton/T, therefore we get
+Ton_max=alpha_max*T; // calculation of maximum ON-period of MOSFET
+// since Edc*Is=E0*I0,  therefore we get
+Is=E0*I0/Edc; // calculation of Battery drain current
+L=E0*(Edc_min-E0)/(f*Edc_min*del_I); // calculation of the value of choke required
+printf("\nThe maximum ON-period of MOSFET is \t Ton_max=%.f us",Ton_max*1E6);
+printf("\nThe Battery drain current is \t\t Is=%.2f A",Is);
+printf("\nThe value of choke required is \t\t L=%.f uH",L*1E6);
+// Note: the answers vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.25/Ex8_25.sce b/3311/CH8/EX8.25/Ex8_25.sce
new file mode 100755
index 000000000..7bb4195bd
--- /dev/null
+++ b/3311/CH8/EX8.25/Ex8_25.sce
@@ -0,0 +1,29 @@
+// chapter 8
+// example 8.25
+// fig. 8.44
+// Determine duty cycle, ripple and peak current of inductor, ripple voltage
+// page-518
+clear;
+clc;
+// given
+Edc=6; // in V (dc source)
+E0=18; // in V (average output voltage)
+I0=0.4; // in A (average load current)
+f=20; // in KHz (switching frequency)
+L=250; // in uH
+C=420; // in uH
+// calculate
+f=f*1E3; // changing unit from KHz to Hz
+L=L*1E-6; // changing unit from uH to H
+C=C*1E-6; // changing unit from uF to F
+// since E0=Edc/(1-alpha), therefore we get
+alpha=1-Edc/E0; // calculation of duty cycle
+del_I=Edc*(E0-Edc)/(f*L*E0); // calculation of ripple current of inductor
+Is=I0/(1-alpha);
+I2=Is+del_I/2; // calculation of peak current of inductor
+del_Vc=I0*alpha/(f*C); // calculation of ripple voltage
+printf("\nThe duty cycle is \t\t\t\t alpha=%.4f \t or \t %.2f percent",alpha,alpha*100);
+printf("\nThe ripple current of inductor is \t\t del_I=%.2f A",del_I);
+printf("\nThe peak current of inductor is \t\t I2=%.1f A",I2);
+printf("\nThe ripple voltage of filter cqpacitor is \t del_Vc=%.2f mV",del_Vc*1E3);5
+// Note: the answers vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.26/Ex8_26.sce b/3311/CH8/EX8.26/Ex8_26.sce
new file mode 100755
index 000000000..9893434a7
--- /dev/null
+++ b/3311/CH8/EX8.26/Ex8_26.sce
@@ -0,0 +1,28 @@
+// chapter 8
+// example 8.26
+// fig. 8.45
+// Compute average output voltage, peak-to-peak output ripple voltage, peak-to-peak current of the inductor and peak current of the device
+// page-522-523
+clear;
+clc;
+// given
+Edc=14; // in V (dc source)
+alpha=0.6; // duty cycle
+f=25; // in KHz (switching frequency)
+L=180; // in uH
+C=220; // in uH
+I0=1.5; // in A (average load current)
+// calculate
+f=f*1E3; // changing unit from KHz to Hz
+L=L*1E-6; // changing unit from uH to H
+C=C*1E-6; // changing unit from uF to F
+E0=-Edc*alpha/(1-alpha); // calculation of average output voltage
+del_Vc=I0*alpha/(f*C); // calculation of peak-to-peak output ripple voltage
+del_I=Edc*alpha/(f*L); // calculation of ripple current of inductor
+Is=I0*alpha/(1-alpha); // calculation of average input current
+Ip=Is/alpha+del_I/2; // calculation of peak current of the device
+printf("\nThe average output voltage is \t\t\t E0=%.f V",E0);
+printf("\nThe peak-to-peak output ripple voltage is \t del_Vc=%.2f V",del_Vc);
+printf("\nThe peak-to-peak ripple current of inductor is \t del_I=%.2f A",del_I);
+printf("\nThe peak current of the device is \t\t Ip=%.2f A",Ip);
+// Note: the answers vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.27/Ex8_27.sce b/3311/CH8/EX8.27/Ex8_27.sce
new file mode 100755
index 000000000..0e84cc791
--- /dev/null
+++ b/3311/CH8/EX8.27/Ex8_27.sce
@@ -0,0 +1,28 @@
+// chapter 8
+// example 8.27
+// Determine range of duty cycle, peak-to-peak choke ripple current and average supply current
+// page-523-524
+clear;
+clc;
+// given
+Edc=24; // in V (dc source)
+f=50; // in KHz (switching frequency)
+L=500; // in uH
+E0=15; // in V (average output voltage)
+Edc_max=26; // in V (maximum voltage of dc source)
+Edc_min=21; // in V (maximum voltage of dc source)
+I0=2; // in A (average load current)
+// calculate
+f=f*1E3; // changing unit from KHz to Hz
+L=L*1E-6; // changing unit from uH to H
+// since E0=Edc*alpha/(1-alpha), therefore we get
+alpha_max=1/((Edc_min/E0)+1); // calculation of upper limit of duty cycle
+alpha_min=1/((Edc_max/E0)+1); // calculation of lower limit of duty cycle
+alpha_normal=1/((Edc/E0)+1); // calculation of normal duty cycle
+del_I=Edc*alpha_normal/(f*L); // calculation of peak-to-peak choke ripple current
+// since Edc*Is=E0*I0, therefore we get
+Is=E0*I0/Edc; // calculation of average supply current
+printf("\nThe duty cycle varies from \t\t\t\t\t\t %.3f to %.3f",alpha_min,alpha_max);
+printf("\nThe peak-to-peak choke ripple current for normal supply voltage is \t del_I=%.1f mA",del_I*1E3);
+printf("\nThe average supply current drawn from battery is \t\t\t Is=%.2f A",Is);
+// Note: the answers vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.28/Ex8_28.sce b/3311/CH8/EX8.28/Ex8_28.sce
new file mode 100755
index 000000000..85d71e6d6
--- /dev/null
+++ b/3311/CH8/EX8.28/Ex8_28.sce
@@ -0,0 +1,39 @@
+// chapter 8
+// example 8.28
+// fig. 8.46
+// Compute average output voltage, average input current, peak-to-peak current of the inductors, peak-to-peak output ripple voltages and peak current of the device
+// page-529-530
+clear;
+clc;
+// given
+Edc=15; // in V (dc source)
+alpha=0.4; // duty cycle
+f=25; // in KHz (switching frequency)
+L1=250; // in uH
+C1=400; // in uH
+L2=380; // in uH
+C2=220; // in uH
+I0=1.25; // in A (average load current)
+// calculate
+f=f*1E3; // changing unit from KHz to Hz
+L1=L1*1E-6; // changing unit from uH to H
+C1=C1*1E-6; // changing unit from uF to F
+L2=L2*1E-6; // changing unit from uH to H
+C2=C2*1E-6; // changing unit from uF to F
+E0=-Edc*alpha/(1-alpha); // calculation of average output voltage
+Is=I0*alpha/(1-alpha); // calculation of average input current
+del_I1=Edc*alpha/(f*L1); // calculation of ripple current of inductor L1 
+del_Vc1=Is*(1-alpha)/(f*C1); // calculation of peak-to-peak output ripple voltage of capacitor C1
+del_I2=Edc*alpha/(f*L2); // calculation of ripple current of inductor L2
+del_Vc2=alpha*Edc/(8*C2*L2*f^2); // calculation of peak-to-peak output ripple voltage of capacitor C2
+V_DF=E0; // calculation of average voltage across diode
+I_L2=I0*E0/V_DF; // calculation of average current in inductor L2
+Ip=Is+del_I1/2+I_L2+del_I2/2; // calculation of peak current of the device
+printf("\nThe average output voltage is \t\t\t\t\t E0=%.f V",E0);
+printf("\nThe average input voltage is \t\t\t\t\t Is=%.2f A",Is);
+printf("\nThe peak-to-peak ripple current of inductor L1 is \t\t del_I1=%.2f A",del_I1);
+printf("\nThe peak-to-peak output ripple voltage of capacitor C1 is \t del_Vc1=%.2f mV",del_Vc1*1E3);
+printf("\nThe peak-to-peak ripple current of inductor L2 is \t\t del_I2=%.2f A",del_I2);
+printf("\nThe peak-to-peak output ripple voltage  of capacitor C2 is \t del_Vc2=%.2f mV",del_Vc2*1E3);
+printf("\nThe peak current of the device is \t\t\t\t Ip=%.2f A",Ip);
+// Note: the answers vary slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.3/Ex8_3.sce b/3311/CH8/EX8.3/Ex8_3.sce
new file mode 100755
index 000000000..202559974
--- /dev/null
+++ b/3311/CH8/EX8.3/Ex8_3.sce
@@ -0,0 +1,25 @@
+// chapter 8
+// example 8.3
+// Determine average and rms output voltage, chopper efficiency and effective input resistance
+// page-440-441
+clear;
+clc;
+// given
+Edc=200; // in V (input voltage)
+R=15; // in ohm
+Ed=2.5; // in V (voltage drop when the chopper is ON)
+f=1; // in KHz (chopper frequency)
+alpha=50; // in percent (duty cycle)
+// calculate
+f=f*1E3;
+T=1/f;// calculation of time period of chopper
+E0=(alpha/100)*(Edc-Ed);// calculation of average output voltage
+E0_rms=sqrt(alpha/100)*(Edc-Ed);// calculation of rms output voltage
+I0_rms=E0_rms/R;// calculation of rms output current
+Po=E0_rms*I0_rms;// calculation of output power
+Is=(Edc-Ed)/R;// calculation of average output current
+Pi=(1/T)*Edc*Is*integrate('1','t',0,((alpha/100)*T));// calculation of input power
+neta=Po/Pi;// calculation of chopper efficiency
+printf("\nThe average output voltage is \t E0=%.2f V",E0);
+printf("\nThe rms output voltage is \t E0_rms=%.3f V",E0_rms);
+printf("\nThe chopper efficiency is \t neta=%.2f percent",neta*100);
\ No newline at end of file
diff --git a/3311/CH8/EX8.4/Ex8_4.sce b/3311/CH8/EX8.4/Ex8_4.sce
new file mode 100755
index 000000000..2d9b528a6
--- /dev/null
+++ b/3311/CH8/EX8.4/Ex8_4.sce
@@ -0,0 +1,15 @@
+// chapter 8
+// example 8.4
+// Calculate the required pulse width
+// page-442
+clear;
+clc;
+// given
+Edc=220; // in V (dc source)
+E0=500; // in V (load voltage)
+Toff=80; // in us (blocking period of thyrostor)
+// calculate
+// since E0=Edc*(Ton+Toff)/Toff, therefore we get
+Ton=(E0/Edc)*Toff-Toff;// calculation of required pulse width
+printf("\nThe time required pulse width is \t Ton=%.1f us",Ton);
+// Note: the answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.5/Ex8_5.sce b/3311/CH8/EX8.5/Ex8_5.sce
new file mode 100755
index 000000000..8b4ccfd4a
--- /dev/null
+++ b/3311/CH8/EX8.5/Ex8_5.sce
@@ -0,0 +1,19 @@
+// chapter 8
+// example 8.5
+// Calculate the conduction and blocking period of the thyristor
+// page-446
+clear;
+clc;
+// given
+Edc=220; // in V (dc source)
+f=2; // in Khz (chopper frequency)
+E0=170; // in V (load voltage)
+// calculate
+f=f*1E3;
+// since E0=Edc*Ton*f, therefore we get
+Ton=E0/(Edc*f);// calculation of conduction period of the thyristor
+T=1/f; // calculation of chopping period
+Toff=T-Ton; // calculation of  blocking period of the thyristor
+printf("\nThe conduction period of the thyristor is \t Ton=%.3f s",Ton*1E3);
+printf("\nThe blocking period of the thyristor is \t Toff=%.3f s",Toff*1E3);
+// Note: the answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.6/Ex8_6.sce b/3311/CH8/EX8.6/Ex8_6.sce
new file mode 100755
index 000000000..dd42a02c0
--- /dev/null
+++ b/3311/CH8/EX8.6/Ex8_6.sce
@@ -0,0 +1,23 @@
+// chapter 8
+// example 8.6
+// Calculate limit of current pulsation, chopping frequency, duty cycle and output voltage
+// page-446
+clear;
+clc;
+// given
+Edc=110; // in V (dc source)
+Ton=15; // in ms (conduction period of the thyristor)
+Toff=12; // in ms (blocking period of the thyristor)
+I0_max=300; // in A (maximum possible accelerating current)
+I0_min=140; // in A (lower limit of current plusation)
+// calculate
+limit=I0_max-I0_min; // calculation of limit of current pulsation
+T=Ton+Toff; // calculation of chopping period
+f=1/(T*1E-3); // calculation of chopping frequency
+alpha=Ton/T; // calculation of duty cycle
+E0=alpha*Edc; // calculation of output voltage
+printf("\nThe limit of current pulsation is \t %.f A",limit);
+printf("\nThe chopping frequency is \t\t f=%.f Hz",f);
+printf("\nThe duty cycle is \t\t\t alpha=%.2f ",alpha);
+printf("\nThe output voltage is \t\t\t E0=%.2f V",E0);
+// Note: the answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.7/Ex8_7.sce b/3311/CH8/EX8.7/Ex8_7.sce
new file mode 100755
index 000000000..ad1596191
--- /dev/null
+++ b/3311/CH8/EX8.7/Ex8_7.sce
@@ -0,0 +1,54 @@
+// chapter 8
+// example 8.7
+// Compute following quantities
+// whether load current is continuous, Average output current, maximum & minimum values of steady-state output current, rms values of 1st, 2nd, 3rd harmonics of load current, Average value of source current, input power, power absorbed by the back emf Eb and power loss in the reistor, RMS value of uotput current
+// page-459-460
+clear;
+clc;
+// given
+Edc=220; // in V (dc source)
+f=500; // in Hz (chopping frequency)
+alpha=0.3; // duty cycle
+R=1; // in ohm
+L=3; // in mH
+Eb=23; // in V (back emf)
+// calculate
+L=L*1E-3; // changing unit from mH to H
+tou=L/R;
+T=1/f;
+g=Eb/Edc;
+w=2*%pi*f;
+alpha_1=(tou/T)*log(1+g*(exp(T/tou)-1));
+if alpha>alpha_1 then
+    printf("\nThe load current is continuous.");
+else
+    printf("\nThe load current is discontinuous.");
+end
+I0_avg=(alpha*Edc-Eb)/R;
+printf("\n\nThe average output current is \t\t\t\t I0_avg=%.f A",I0_avg);
+// Since alpha=Ton/T, therefore we get
+Ton=alpha*T;
+I0_max=(Edc/R)*((1-exp(-Ton/tou))/(1-exp(-T/tou)))-Eb/R;
+printf("\n\nThe maximum steady-state output current is \t\t I0_max=%.2f A",I0_max);
+I0_min=(Edc/R)*((exp(Ton/tou)-1)/(exp(T/tou)-1))-Eb/R;
+printf("\n\nThe minimum steady-state output current is \t\t I0_min=%.2f A",I0_min);
+Value=0; // a temporary variable to calculate few variables
+for n=1:3
+    Z=sqrt(R^2+(w*n*L)^2);
+    I=(2*Edc*sin(n*%pi*alpha))/(n*sqrt(2)*%pi)/Z;
+    printf("\n\nThe %.fth harmonic of steady-state output current is \t I_%.f=%.3f A",n,n,I);
+    Value=Value+I^2;
+end
+I_TAV=(Edc-Eb)*alpha/R-(L/(R*T))*(I0_max-I0_min);
+printf("\n\nThe average value of source current is \t\t\t I_TAV=%.f3 A",I_TAV);
+Pin=Edc*I_TAV;
+P_absorbed=Eb*I0_avg;
+P_loss=Pin-P_absorbed;
+printf("\n\nThe input power is \t\t\t\t\t Pin=%.1f W",Pin);
+printf("\n\nThe power absorbed by load emf is \t\t\t P_absorbed=%.f W",P_absorbed);
+printf("\n\nThe power loss in the resistor is \t\t\t P_loss=%.1f W",P_loss);
+Irms_2_3=sqrt(I0_avg^2+Value);
+printf("\n\nThe rms current using the result of (ii) and (iii) is \t Irms=%.2f A",Irms_2_3);
+Irms_4=sqrt(P_loss/R);
+printf("\n\nThe rms current using the result of (iv) is \t\t Irms=%.2f A",Irms_4);
+// Note: the answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.8/Ex8_8.sce b/3311/CH8/EX8.8/Ex8_8.sce
new file mode 100755
index 000000000..cfb8ef6aa
--- /dev/null
+++ b/3311/CH8/EX8.8/Ex8_8.sce
@@ -0,0 +1,60 @@
+// chapter 8
+// example 8.8
+// Calculate the mean values of load voltage and current
+// page-460-462
+clear;
+clc;
+// given
+Edc=80; // in V (dc source)
+T=2; // in ms (chopping period)
+L=8; // in mH
+R=4; // in ohm
+Ton_Toff_1= 1/1;
+Ton_Toff_2= 4/1;
+Ton_Toff_3= 1/4;
+// calculate
+L=L*1E-3; // changing unit from mH to H
+tou=L/R;
+T=T*1E-3;
+//part-a
+// since Ton/Toff=1/1 therefore Ton=Toff or 
+Ton=T/2;
+Toff=Ton;
+I0_max=(Edc/R)*((1-exp(-Ton/tou))/(1-exp(-T/tou)));
+I0_min=I0_max*exp(-Toff/tou);
+E0=Edc*(Ton/T);
+I0_av=E0/R;
+printf("\nWhent Ton/Toff=1/1,")
+printf("\n\t\tThe maximum output current is \t\t I0_max=%.2f A", I0_max);
+printf("\n\t\tThe minimum output current is \t\t I0_min=%.2f A", I0_min);
+printf("\n\t\tThe mean value of load voltage is \t E0=%.f V",E0);
+printf("\n\t\tThe mean value of load current is \t I0_av=%.f A",I0_av);
+//part-b
+// since Ton/Toff=4/1 therefore Ton=4Toff and Ton+Toff=T or 5*Toff=T therefore we get
+Toff=T/5;
+Ton=4*Toff;
+I0_max=(Edc/R)*((1-exp(-Ton/tou))/(1-exp(-T/tou)));
+I0_min=I0_max*exp(-Toff/tou);
+E0=Edc*(Ton/T);
+I0_av=E0/R;
+printf("\nWhent Ton/Toff=4/1,")
+printf("\n\t\tThe maximum output current is \t\t I0_max=%.2f A", I0_max);
+printf("\n\t\tThe minimum output current is \t\t I0_min=%.2f A", I0_min);
+printf("\n\t\tThe mean value of load voltage is \t E0=%.f V",E0);
+printf("\n\t\tThe mean value of load current is \t I0_av=%.f A",I0_av);
+//part-c
+// since Ton/Toff=1/4 therefore Toff=4*Toff and Ton+Toff=T or 5*Ton=T therefore we get
+Ton=T/5;
+Toff=5*Ton;
+I0_max=(Edc/R)*((1-exp(-Ton/tou))/(1-exp(-T/tou)));
+I0_min=I0_max*exp(-Toff/tou);
+E0=Edc*(Ton/T);
+I0_av=E0/R;
+printf("\nWhent Ton/Toff=1/4,")
+printf("\n\t\tThe maximum output current is \t\t I0_max=%.2f A", I0_max);
+printf("\n\t\tThe minimum output current is \t\t I0_min=%.2f A", I0_min);
+printf("\n\t\tThe mean value of load voltage is \t E0=%.f V",E0);
+printf("\n\t\tThe mean value of load current is \t I0_av=%.f A",I0_av);
+
+// Note: 1 The answer for I0_min of part-b is wrong in the book due to calculation mistake.
+//       2.the answers varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH8/EX8.9/Ex8_9.sce b/3311/CH8/EX8.9/Ex8_9.sce
new file mode 100755
index 000000000..61e21eeae
--- /dev/null
+++ b/3311/CH8/EX8.9/Ex8_9.sce
@@ -0,0 +1,24 @@
+// chapter 8
+// example 8.9
+// fig. Ex. 8.9
+// Find the chopping frequency
+// page-463
+clear;
+clc;
+// given
+Edc=400; // in V (dc source)
+L=0.05; // in H
+R=0; // in ohm
+alpha=0.3; // duty cycle
+dI0=8; // in A (load current excursion)
+// calculate
+E0=alpha*Edc;
+Eb=E0;
+// Since VT_area=L*dI0 and VT_area=(Edc-Eb)*Ton, therefore we get
+// (Edc-Eb)*Ton=L*dI0 or 
+Ton=L*dI0/(Edc-Eb); // calculation of ON period of chopper
+// Since alpha=Ton/T, therefore
+T=Ton/alpha; // calculation of chopping period
+f=1/T; // calculation of chopping frequency
+printf("\nThe chopping frequency to limit the load current excursion to %.f A is \t f=%.2f Hz",dI0,f);
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH9/EX9.1/Ex9_1.sce b/3311/CH9/EX9.1/Ex9_1.sce
new file mode 100755
index 000000000..6c93dc88f
--- /dev/null
+++ b/3311/CH9/EX9.1/Ex9_1.sce
@@ -0,0 +1,29 @@
+// chapter 9
+// example 9.1
+// Compute rms value of output voltage, fundamental component of the output-voltage waveform, first five harmonics of the output voltage, fundamental power consumed,rms power consumed, rms value by harmonic summation method
+// page-544
+clear;
+clc;
+// given
+Edc_2=96; // in V (dc source at center tapped)
+R=10; // in ohm
+// calculate
+Edc=2*Edc_2;
+E0_rms=Edc/2; // calculation of rms value of output voltage
+printf("\nThe rms value of output voltage is \t\t\t E0_rms=%.f V",E0_rms);
+E1_fund=sqrt(2)/%pi*Edc; // calculation of fundamental component of the output-voltage waveform
+printf("\n\nThe fundamental component of the output voltage is \t E1_fund=%.2f V\n",E1_fund);
+P0_fund=E1_fund^2/R; // calculation of fundamental power consumed
+P0_rms=E0_rms^2/R; // calculation of rms power consumed
+E0_rms_H=E1_fund^2;
+for n=3:2:11
+    E0=E1_fund/n;
+    printf("\n The %.f harmonic voltage is \t %.2f V",n,E0); // calculation of rms value of voltage by harmonic summation method
+    E0_rms_H=E0_rms_H+E0^2;
+end
+E0_rms_H=sqrt(E0_rms_H); // calculation of rms value by harmonic summation method
+printf("\n\nThe fundamental power consumed is \t\t\t\t P0_fund=%.2f W",P0_fund);
+printf("\nThe rms power consumed is \t\t\t\t\t P0_rms=%.2f W",P0_rms);
+printf("\n\nThe rms value determined by harmonic summation method is \t E0_rms=%.2f V",E0_rms_H);
+printf("\n\n The two values of rms voltages as determined are almost equal.");
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH9/EX9.10/Ex9_10.sce b/3311/CH9/EX9.10/Ex9_10.sce
new file mode 100755
index 000000000..38fce5069
--- /dev/null
+++ b/3311/CH9/EX9.10/Ex9_10.sce
@@ -0,0 +1,21 @@
+// chapter 9
+// example 9.10
+// Determine fundamental output voltage and first five dominant harmonics
+// page-574
+clear;
+clc;
+// given
+Edc=280; // in V (battery voltage)
+M=0.8; // modulation index
+Mf=24; // carrier ratio
+// calculate
+E0_fund=M*Edc/sqrt(2); // calculation of Fundamental output voltage
+printf("\nThe Fundamental output voltage is \t E0_rms=%.2f V",E0_fund);
+printf("\n\nThe first five dominant harmonics are \t n= ")
+for n=2:2:6
+    N1=n*Mf-1;
+    N2=n*Mf+1;
+    printf("%.f, %.f, ",N1,N2);
+end
+printf(" ... etc");
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH9/EX9.12/Ex9_12.sce b/3311/CH9/EX9.12/Ex9_12.sce
new file mode 100755
index 000000000..4980feb75
--- /dev/null
+++ b/3311/CH9/EX9.12/Ex9_12.sce
@@ -0,0 +1,18 @@
+// chapter 9
+// example 9.12
+// Determine rms value of the output line and phase voltages, rms value of the fundamental component of the line and phase voltage
+// page-582
+clear;
+clc;
+// given
+Edc=500; // in V (source voltage)
+// calculate
+E_line_rms=sqrt(2/3)*Edc; // calculation of rms value of the output line voltage
+E_phase_rms=E_line_rms/sqrt(3); // calculation of rms value of the phase voltage
+E_line_fund=4*Edc*cosd(30)/(sqrt(2)*%pi); // calculation of rms value of the fundamental component of the line voltage
+E_phase_fund=E_line_fund/sqrt(3); // calculation of rms value of the fundamental component of the phase voltage
+printf("\nThe rms value of the output line voltage is \t\t\t\t E_line_rms=%.f V",E_line_rms);
+printf("\nThe rms value of the phase voltage is \t\t\t\t\t E_phase_rms=%.2f V",E_phase_rms);
+printf("\nThe rms value of the fundamental component of the line voltage is \t E_line_fund=%.f V",E_line_fund);
+printf("\nThe rms value of the fundamental component of the line voltage is \t E_phase_fund=%.2f V",E_phase_fund);
+// Note: The answer varies slightly due to precise calculations and the answer in the book is rounded off
\ No newline at end of file
diff --git a/3311/CH9/EX9.14/Ex9_14.sce b/3311/CH9/EX9.14/Ex9_14.sce
new file mode 100755
index 000000000..259b2eb9c
--- /dev/null
+++ b/3311/CH9/EX9.14/Ex9_14.sce
@@ -0,0 +1,57 @@
+// chapter 9
+// example 9.14
+// Determine rms line and phase voltage, rms line and phase voltage at fundamental frequency, THD, DR, HF and DF of lowest order harmonic, load power and average and rms switch current
+// page-584-585
+clear;
+clc;
+// given
+Edc=200; // in V (source voltage)
+R=10; // in ohm
+L=20; // in mH
+f0=50; // in Hz (invertor frequency)
+// calculate
+L=L*1E-3; // changing unit from mH to H
+w=2*%pi*f0; // calculation of angular velocity
+E_L=sqrt(2/3)*Edc; // calculation of rms value of the output line voltage
+E_P=E_L/sqrt(3); // calculation of rms value of the phase voltage
+E_L1=4*Edc*cosd(30)/(sqrt(2)*%pi); // calculation of rms value of the fundamental component of the line voltage
+E_P1=E_L1/sqrt(3); // calculation of rms value of the fundamental component of the phase voltage
+printf("\nThe rms value of the output line voltage is \t\t\t\t E_L=%.2f V",E_L);
+printf("\nThe rms value of the phase voltage is \t\t\t\t\t E_P=%.2f V",E_P);
+printf("\nThe rms value of the fundamental component of the line voltage is \t E_L1=%.2f V",E_L1);
+printf("\nThe rms value of the fundamental component of the line voltage is \t E_P1=%.2f V",E_P1);
+E1_rms=2*Edc/(sqrt(2)*%pi);
+E0_rms=(Edc/2);
+THD=sqrt(E_L^2-E_L1^2)/E_L1; // calculation of total harmonic distortion
+printf("\\nnThe total harmonic distortion is \t THD=%.4f or \t %.2f percent",THD,THD*100);
+K=0;
+for n=5:2:11
+    E_Ln=4*Edc*cos(n*%pi/6)/(n*%pi*sqrt(2));
+    E_Ln_n2=(E_Ln/n^2)^2;
+    K=K+E_Ln_n2;
+end
+K=sqrt(K);
+DF=K/E_L1; // calculation of distortion factor
+printf("\nThe distortion factor is \t\t DF=%f or \t %.3f percent",DF,DF*100);
+E_L5=4*Edc*cos(5*%pi/6)/(5*%pi*sqrt(2));
+HF5=abs(E_L5/E_L1); // calculation of lowest order of harmonic factor
+DF5=abs((E_L5/5^2)/E_L1); // calculation of lowest order of distortion factor
+printf("\nThe lowest order harmonic factor is \t HF5=%.3f or \t %.2f percent",HF5,HF5*100);
+printf("\nThe lowest order distortion factor is \t DF5=%.3f or \t %.2f percent",DF5,DF5*100);
+I=0; // initialisation
+for n=1:2:17
+    Z_L=sqrt(R^2+(n*w*L)^2);
+    theta=atand(n*w*L/R);
+    I_L=4*Edc*cos(n*%pi/6)/(n*%pi*Z_L);
+    I=I+I_L^2;
+end
+I=sqrt(I)/sqrt(2); // calculation of load current
+P0=3*I^2*R; // calculation of load power
+Is=P0/Edc; // calculation of average supply current
+I_T_avg=Is/3; // calculation of average switch current
+I_T_rms=I/sqrt(2); // calculation of rms switch current
+printf("\n\nThe load power is \t\t P0=%.2f kW",P0*1E-3);
+printf("\nThe average switch current is \t I_T_avg=%.2f A",I_T_avg);
+printf("\nThe rms switch current is \t I_T_rms=%.2f A",I_T_rms);
+// Note: 1. There is calculation mistake while calculating load current and hence the answers for P0, I_T_avg, I_T_rms are wrong in the book
+//       2.The answer varies slightly due to precise calculations and the answer in the book is rounded off
diff --git a/3311/CH9/EX9.17/Ex9_17.sce b/3311/CH9/EX9.17/Ex9_17.sce
new file mode 100755
index 000000000..991b6b798
--- /dev/null
+++ b/3311/CH9/EX9.17/Ex9_17.sce
@@ -0,0 +1,19 @@
+// chapter 9
+// example 9.17
+// Determine dc voltage, rms line and phase voltages and Device voltage ratings
+// page-591
+clear;
+clc;
+// given
+E1_line=415; // fundamental line voltage
+// calculate
+// since E1_line=(sqrt(2)/%pi)*Edc*1.5, therefore we get
+Edc=E1_line*(%pi/(sqrt(2)*1.5)); // calculation of dc voltage
+E_rms_line=Edc/sqrt(2); // calculation of rms line voltage
+E_rms_phase=E_rms_line/sqrt(3); // calculation of rms phase voltage
+V_CEO=1.5*Edc; // calculation of Device voltage ratings
+printf("\nThe dc voltage is \t\t Edc=%.f V", Edc);
+printf("\nThe rms line voltage is \t E_rms_line=%.2f V",E_rms_line);
+printf("\nThe rms phase voltage is \t E_rms_phase=%.2f V",E_rms_phase);
+printf("\nThe Device voltage ratings is \t V_CEO=%.1f V",V_CEO);
+// Note: The answer varies slightly due to precise calculations
\ No newline at end of file
diff --git a/3311/CH9/EX9.18/Ex9_18.sce b/3311/CH9/EX9.18/Ex9_18.sce
new file mode 100755
index 000000000..97ea82ee0
--- /dev/null
+++ b/3311/CH9/EX9.18/Ex9_18.sce
@@ -0,0 +1,37 @@
+// chapter 9
+// example 9.18
+// Desig a series invertor circuit
+// page-606
+clear;
+clc;
+// given
+f0=1, fr=5; // in KHz (range of frequency of operation)
+Rmin=25, Rmax=100; // in ohm (range of load resistance)
+Ip=3;  // in A
+Edc=100; // in V (dc source)
+AF=0.5; // attenuation factor (assumption as done in the book)
+// calculate
+f0=f0*1E3; // changing unit from KHz to Hz
+fr=fr*1E3; // changing unit from KHz to Hz
+wr=2*%pi*fr; // calculation of upper limit of angular velocity 
+w0=2*%pi*f0; // calculation of lower limit of angular velocity
+L=-Rmax/(8*fr*log(AF)); // calculation of inductance
+C=(1/L)*(1/(wr^2+(Rmax/(2*L))^2)); // calculation of capacitance
+Ec=Edc*(exp(-Rmin*%pi/(2*wr*L))/(1-exp(-Rmin*%pi/(2*wr*L)))); // calculation of capacitor voltage
+I_peak=(Ec+Edc)/(wr*L)*exp(-Rmin*%pi/(4*wr*L)); // calculation of peak current
+// since V_BO>=Ec+Edc, therefore 
+V_BO=Ec+Edc; // calculation of forward blocking voltage rating
+// since I_T>=I-peak, therefore 
+I_T=(I_peak+1); // calculation of Thyristor current
+Toff=%pi*((1/w0)-(1/wr)); // calculation of Thyristor off-time
+// since I_T>=I-peak, therefore 
+tq=Toff*1E3-0.1; // calculation of invertor trun off-time
+printf("\nThe inductance \t\t\t L=%.1f mH",L*1E3);
+printf("\nThe capacitance \t\t C=%.2f uF",C*1E6);
+printf("\nThe capacitor voltage \t\t Ec=%.2f V",Ec);
+printf("\nThe peak current \t\t I_peak=%.2f A",I_peak);
+printf("\nThe forward blocking voltage \t V_BO>=%.f V",V_BO);
+printf("\nThe Thyristor current \t\t I_T=%.f A",I_T);
+printf("\nThe Thyristor turn-off time \t Toff=%.1f ms",Toff*1E3);
+printf("\nThe invertor turn-off time \t tq=%.1f ms",tq);
+// Note: The answer varies slightly due to precise calculations and round off as done in the book
\ No newline at end of file
diff --git a/3311/CH9/EX9.19/Ex9_19.sce b/3311/CH9/EX9.19/Ex9_19.sce
new file mode 100755
index 000000000..583cb654f
--- /dev/null
+++ b/3311/CH9/EX9.19/Ex9_19.sce
@@ -0,0 +1,45 @@
+// chapter 9
+// example 9.19
+// Design a self-commutated invertor circuit and compute output power
+// page-608-609
+clear;
+clc;
+// given
+f0=3; // in KHz
+R=5; // in ohm (load resistance)
+L=5; // in mH
+Edc=100; // in V (dc source)
+// calculate
+f0=f0*1E3; // changing unit from KHz to Hz
+fr=1.35*f0; // calculation of resonant frequency
+L=L*1E-3; // changing unit from mH to H
+w0=2*%pi*f0; // calculation of normal angular frequency
+wr=2*%pi*fr; // calculation of resonant angular velocity
+// since L/L1=200, therefore we get
+L1=L/200; // calculation of inductance L1
+// since fr=1/(2*%pi*sqrt(2*L1*C)),  therefore we get
+C=(1/(2*%pi*fr))^2/(2*L1); // calculation of capacitance
+tou=R*C; // calculation of time constant
+T=1/f0; // calculation of time period
+K=exp(-T/(2*tou)); // calculation of attenuation factor
+Z0=(R*%i*w0*L)/((R+(%i*w0*L))); // calculation of output impedence
+Z0_magnitude=abs(Z0);
+I=(Edc/Z0_magnitude)*(1/(1-4*tou*((1-K)/(1+K)))); // calculation of current flowing through Thyristor
+E0_max=I*Z0_magnitude*(1-2*K/(1+K)); // calculation of maximum output vltage
+E0_rms=E0_max/sqrt(2); // calculation of rms output voltage
+V_BO=2*(Edc+E0_max); // calculation of forward blocking voltage rating
+I_T=2*I; // calculation of Thyristor current
+tq=tou*log(2/(1+K)); // calculation of invertor trun off-time
+Vc=2*E0_max; // calculation of capacitor voltage
+P0=(E0_max*E0_rms/R)*cosd(atand(imag(Z0),real(Z0))); // calculation of output power
+printf("\nThe resonant frequency is \t\t\t fr=%.2f KHz",fr*1E-3);
+printf("\nThe inductance L1 is \t\t\t\t L1=%.f uH",L1*1E6);
+printf("\nThe capacitance is \t\t\t\t C=%.f uF",C*1E6);
+printf("\nThe current flowing through Thyristor is \t I=%.f A",I);
+printf("\nThe maximum output voltage is \t\t\t E0_max=%.2f V",E0_max);
+printf("\nThe rms output voltage is \t\t\t E0_rms=%.2f V",E0_rms);
+printf("\nThe forward blocking voltage is \t\t V_BO>=%.2f V",V_BO);
+printf("\nThe Thyristor current is \t\t\t I_T=%.f A",I_T);
+printf("\nThe invertor turn-off time is \t\t\t tq=%.1f us",tq*1E6);
+printf("\nThe output power is \t\t\t\t P0=%.2f W",P0);
+// Note: The answer varies slightly due to precise calculations and round off as done in the book
\ No newline at end of file
diff --git a/3311/CH9/EX9.2/Ex9_2.sce b/3311/CH9/EX9.2/Ex9_2.sce
new file mode 100755
index 000000000..810283dcc
--- /dev/null
+++ b/3311/CH9/EX9.2/Ex9_2.sce
@@ -0,0 +1,32 @@
+// chapter 9
+// example 9.2
+// Compute fundamental output-voltage, first five harmonics of the output voltage,rms value by direct integration and harmonic summation method ,output rms and fundamental power  and transistor switch ratings
+// page-547
+clear;
+clc;
+// given
+Edc=48; // in V (dc source)
+R=10; // in ohm
+// calculate
+E1_fund=2*sqrt(2)/%pi*Edc; // calculation of fundamental component of the output-voltage waveform
+printf("\n\nThe fundamental component of the output voltage is \t E1_fund=%.2f V\n",E1_fund);
+E0_rms=Edc; // calculation of rms value of output voltage
+printf("\nThe rms value of output voltage is \t\t\t E0_rms=%.f V\n",E0_rms);
+E0_rms_H=E1_fund^2;
+for n=3:2:11
+    E0=E1_fund/n;
+    printf("\n The %.f harmonic voltage is \t %.2f V",n,E0); // calculation of rms value of voltage by harmonic summation method
+    E0_rms_H=E0_rms_H+E0^2;
+end
+E0_rms_H=sqrt(E0_rms_H); // calculation of rms value by harmonic summation method
+printf("\n\nThe rms value determined by harmonic summation method is \t E0_rms=%.2f V",E0_rms_H);
+P0_rms=E0_rms^2/R; // calculation of rms power consumed
+printf("\n\nThe rms power consumed is \t\t\t\t\t P0_rms=%.2f W",P0_rms);
+P0_fund=E1_fund^2/R; // calculation of fundamental power consumed
+printf("\n\nThe fundamental power consumed is \t\t\t\t P0_fund=%.2f W",P0_fund);
+V_CE0=Edc;
+I_T_peak=Edc/R;
+I_T_rms=Edc/(sqrt(2)*R);
+I_T_avg=Edc/(2*R);
+printf("\n\nThe transistor switch ratings are \t VCE0=%.f V \t I_T_peak=%.1f A \t I_T_rms=%.3f A \t I_T_avg=%.1f A",V_CE0,I_T_peak,I_T_rms,I_T_avg);
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH9/EX9.20/Ex9_20.sce b/3311/CH9/EX9.20/Ex9_20.sce
new file mode 100755
index 000000000..65ac31dfa
--- /dev/null
+++ b/3311/CH9/EX9.20/Ex9_20.sce
@@ -0,0 +1,37 @@
+// chapter 9
+// example 9.20
+// Design a parallel invertor
+// page-614
+clear;
+clc;
+// given
+f=50; // in Hz
+E=200; // in V
+Edc=40; // in V
+I_L=2; // in A
+tq=40; // in us (assumption as done in the book)
+E_amplitude=415; // in V (fundamental frequency amplitude of voltage assumption as done in the book)
+Bmax=1; // in Wb/m^2 (assumption for flux density as done in the book)
+A=25; // in cm^2 (assumption for cross-section area as done in the book)
+// calculate
+tq=tq*1E-6; // changing unit from us to s
+A=A*1E-4; // changing unit from cm^2 to m^2
+// since Edc*sqrt(C/L)=I_L and sqrt(C*L)=3*tq/%pi, therefore multiplying both we get
+// Edc*C=I_L*3*tq/%pi, therefore we get
+C=(I_L*3*tq/%pi)/Edc; // calculation of capacitance
+L=(1/(I_L/Edc)^2)*C; // calculation of inductance
+Vc=2*Edc; // calculation of capacitor voltage
+N2=E_amplitude/(sqrt(2)*4.44*f*A); // calculation of number of turns in secondary winding
+// since N2/(1/2*N1)=6, therefore we get
+N1=2*N2/6; // calculation of number of turns in primary winding
+V_BO=2*Edc; // calculation of forward blocking voltage rating
+I_T=2*E/Edc*I_L; // calculation of Thyristor current
+printf("\nThe inductance is \t\t\t\t L=%.1f uH",L*1E6);
+printf("\nThe capacitance is \t\t\t\t C=%.1f uF",C*1E6);
+printf("\nThe capacitor voltgae is \t\t\t Vc=%.f V",Vc)
+printf("\nThe number of turns in secondary winding is \t N2=%.f",N2);
+printf("\nThe number of turns in primary winding is \t N1=%.f",N1);
+printf("\nThe forward blocking voltage is \t\t V_BO>=%.f V",V_BO);
+printf("\nThe Thyristor current is \t\t\t I_T>=%.f A",I_T);
+// Note: 1. The answer for L and C is wrong in the book due to calculation mistake.
+//       2 The answer vary slightly due to precise calculations and round off as done in the book
\ No newline at end of file
diff --git a/3311/CH9/EX9.21/Ex9_21.sce b/3311/CH9/EX9.21/Ex9_21.sce
new file mode 100755
index 000000000..21af9a1a0
--- /dev/null
+++ b/3311/CH9/EX9.21/Ex9_21.sce
@@ -0,0 +1,23 @@
+// chapter 9
+// exapmle 9.21
+// Calculate rms output voltage at fundamental frequency, output power, average and peak current and peak reverse-blocking voltage
+// page-618
+clear;
+clc;
+// given
+Edc=50; // in V (source voltage)
+R=3; // in ohm
+D=50; // in percent (universal for the circuit used)
+// calculate
+E1=2*Edc/(sqrt(2)*%pi); // calculation of rms output voltage at fundamental frequency
+E_L=Edc/2; // calculation of rms line voltage
+P0=E_L^2/R; // calculation of output power
+I_peak=(Edc/2)/R; // calculation of peak current
+I_av=(D/100)*I_peak; // calculation of average current
+V_BR=2*Edc/2; // calculation of peak reverse-blocking voltage
+printf("\nThe rms output voltage at fundamental frequency is \t E1=%.1f V",E1);
+printf("\nThe output power is \t\t\t\t\t P0=%.2f W",P0);
+printf("\nThe peak current is \t\t\t\t\t I_peak=%.2f A",I_peak);
+printf("\nThe average current is \t\t\t\t\t I_av=%.3f A",I_av);
+printf("\nThe peak reverse-blocking voltage is \t\t\t V_BR=%.f V",V_BR);
+// Note: The answer vary slightly due to precise calculations and round off as done in the book
\ No newline at end of file
diff --git a/3311/CH9/EX9.22/Ex9_22.sce b/3311/CH9/EX9.22/Ex9_22.sce
new file mode 100755
index 000000000..0f2e2e17e
--- /dev/null
+++ b/3311/CH9/EX9.22/Ex9_22.sce
@@ -0,0 +1,24 @@
+// chapter 9
+// example 9.22
+// fig. 9.43 (a)
+// Calculate rms output voltage at fundamental frequency, output power, average and peak current and peak reverse-blocking voltage
+// page-620
+clear;
+clc;
+// given
+Edc=50; // in V (source voltage)
+R=3; // in ohm
+D=50; // in percent (universal for the circuit used)
+// calculate
+E1=4*Edc/(sqrt(2)*%pi); // calculation of rms output voltage at fundamental frequency
+E_L=sqrt(2*Edc^2*integrate('1','t',0,1/2)); // calculation of rms line voltage
+P0=Edc^2/R; // calculation of output power
+I_peak=Edc/R; // calculation of peak current
+I_av=(D/100)*I_peak; // calculation of average current
+V_BR=Edc; // calculation of peak reverse-blocking voltage
+printf("\nThe rms output voltage at fundamental frequency is \t E1=%.1f V",E1);
+printf("\nThe output power is \t\t\t\t\t P0=%.2f W",P0);
+printf("\nThe peak current is \t\t\t\t\t I_peak=%.2f A",I_peak);
+printf("\nThe average current is \t\t\t\t\t I_av=%.3f A",I_av);
+printf("\nThe peak reverse-blocking voltage is \t\t\t V_BR=%.f V",V_BR);
+// Note: The answer vary slightly due to precise calculations and round off as done in the book
\ No newline at end of file
diff --git a/3311/CH9/EX9.23/Ex9_23.sce b/3311/CH9/EX9.23/Ex9_23.sce
new file mode 100755
index 000000000..1894544d9
--- /dev/null
+++ b/3311/CH9/EX9.23/Ex9_23.sce
@@ -0,0 +1,27 @@
+// chapter 9
+// example 9.23
+// What value of C should the load have in order to obtain load commutation of SCR
+// page-620
+clear;
+clc;
+// given
+Edc=50; // in V (source voltage)
+R=3; // in ohm
+wL=12; // in ohm
+T=0.2; // in ms (time period)
+tq=12; // in us
+Toff=1.5*tq;
+// calculate
+T=T*1E-3; // changing unit from ms to s
+Toff=Toff*1E-6; // changing unit from us to s
+phi_w=Toff; // calculation of phi/w
+f=1/T; // calculation of frequency
+w=2*%pi*f; // calculation of angular velocity
+phi=phi_w*w; // calculation of phase angle
+X_L=wL;
+// since Tan(phi)=(X_C-X_L)/R, therefore we get
+X_C=(tan(phi)*R)+X_L; // calculation of capacitive reactance
+// since X_c=1/(w*C), therefore we get
+C=1/(X_C*w); // calculation of required capacitance
+printf("\nThe value of C that the load sholud have in order to obtain load commutation of SCR is \t C=%.2f uF",C*1E6);
+// Note: The answer in the book is wrong due to calculation mistake in calculating the variable phi_w 
\ No newline at end of file
diff --git a/3311/CH9/EX9.24/Ex9_24.sce b/3311/CH9/EX9.24/Ex9_24.sce
new file mode 100755
index 000000000..966a19204
--- /dev/null
+++ b/3311/CH9/EX9.24/Ex9_24.sce
@@ -0,0 +1,19 @@
+// chapter 9
+// example 9.24
+// fig. 9.45
+// Obtain the value of commutating components L and C
+// page-626
+clear;
+clc;
+// given
+I_L_max=80; // in A (maximum load current)
+Edc_min=200; // in V (minimum source voltage)
+tq=40; // in us (turn-off time of SCRs)
+// calculate
+tq=tq*1E-6; // changing unit from us to s
+Toff=1.5*tq; // calculation of circuit turn-off time
+C=0.893*Toff*I_L_max/Edc_min; // calculation of the value of commutating capacitance
+L=0.397*Edc_min*Toff/I_L_max; // calculation of the value of commutating inductance
+printf("\nThe value of commutating capacitance is \t C=%.2f uF",C*1E6);
+printf("\nThe value of commutating inductance is \t\t L=%.2f uH",L*1E6);
+// Note: The answer in the book for C and L is wrong due to calculation mistake 
\ No newline at end of file
diff --git a/3311/CH9/EX9.25/Ex9_25.sce b/3311/CH9/EX9.25/Ex9_25.sce
new file mode 100755
index 000000000..c1a4921b0
--- /dev/null
+++ b/3311/CH9/EX9.25/Ex9_25.sce
@@ -0,0 +1,26 @@
+// chapter 9
+// example 9.25
+// fig. 9.47
+// Obtain the value of commutating components and the value of resistance
+// page-628
+clear;
+clc;
+// given
+Edc=300; // in V (source voltage)
+neta=15; // in percent (variation of maximum and minimum dc voltage from dc source voltage)
+I_L_max=100; // in A (maximum load current)
+I_L_min=20; // in A (minimum load current)
+tq=20; // in us (turn-off time of SCRs)
+safety_factor=2; // assumption
+// calculate
+tq=tq*1E-6; // changing unit from us to s
+Toff=2*tq; // calculation of circuit turn-off time
+Edc_min=Edc*(1-neta/100); // calculation of minimum dc voltage
+Edc_max=Edc*(1+neta/100); // calculation of maximum dc voltage
+C=0.893*Toff*I_L_max/Edc_min; // calculation of the value of commutating capacitance
+L=0.397*Edc_min*Toff/I_L_max; // calculation of the value of commutating inductance
+R=2*sqrt(L/C); // calculation of the value of resistance
+printf("\nThe value of commutating capacitance is \t C=%.f uF",C*1E6);
+printf("\nThe value of commutating inductance is \t\t L=%.1f uH",L*1E6);
+printf("\nthe value of resistance is \t\t\t R=%.1f ohm",R);
+// Note: The answer in the book for C and L is wrong due to calculation mistake 
\ No newline at end of file
diff --git a/3311/CH9/EX9.26/Ex9_26.sce b/3311/CH9/EX9.26/Ex9_26.sce
new file mode 100755
index 000000000..df0870e95
--- /dev/null
+++ b/3311/CH9/EX9.26/Ex9_26.sce
@@ -0,0 +1,32 @@
+// chapter 9
+// example 9.26
+// fig. Ex.9.26(a) and Ex. 9.26(b)
+// Find the rms load current, load-power and thyristor ratings
+// page-628-630
+clear;
+clc;
+// given
+Edc=600; // in V (source voltage)
+R=15; // in ohm (resistance per phase)
+alpha1=120, alpha2=180; // in degree
+// calculate
+// part-a
+Ip=Edc/(2*R); // calculation of load current amplitude
+Irms=sqrt((1/(2*%pi))*Ip^2*(integrate('1','theta',0,(alpha1*(%pi/180)))+integrate('1','theta',(alpha2*(%pi/180)),(5*%pi/3)))); // calculation of rms load current
+P0=3*Irms^2*R; // calculation of load-power
+I_T_rms=sqrt(Ip^2/3); // calculation of thyristor rms current
+printf("\nFor %.f degree conduction, \n",alpha1);
+printf("\nThe rms load current is \t Irms=%.2f A",Irms);
+printf("\nThe load-power is \t\t P0=%.f kW",P0*1E-3);
+printf("\nThe thyristor rms current is \t I_T_rms=%.1f A",I_T_rms);
+// part-b
+R0=R+R/2; // calculation of load on invertor
+I1=Edc/R0; // calculation of current I1
+I2=I1/2; // calculation of current I2
+Irms1=sqrt((1/(2*%pi))*(I2^2*integrate('1','theta',0,(alpha1*%pi/180))+I1^2*integrate('1','theta',(alpha1*%pi/180),(4*%pi/3))+I2^2*integrate('1','theta',(4*%pi/3),(2*%pi)))); // calculation of rms load current Irms1
+Irms2=I1/2; // calculation of rms load current Irms2
+P0=3*Irms1^2*R; // calculation of load-power
+printf("\n\nFor %.f degree conduction, \n",alpha2);
+printf("\nThe rms load currents are \t Irms1=%.2f A \t Irms2=%.2f A",Irms1,Irms2);
+printf("\nThe load-power is \t\t P0=%.2f kW",P0*1E-3);
+// Note: 1. The wrong values of angle theta has been used in the book for calculating the rms load current in both cases. But the answer in the book is right. So I have used correct values and the answer is same as in the book with little variation due to precise calculation
\ No newline at end of file
diff --git a/3311/CH9/EX9.27/Ex9_27.sce b/3311/CH9/EX9.27/Ex9_27.sce
new file mode 100755
index 000000000..99fc98f0b
--- /dev/null
+++ b/3311/CH9/EX9.27/Ex9_27.sce
@@ -0,0 +1,30 @@
+// chapter 9
+// example 9.27
+// Determine commutating capacitor, load current, Fcritical and Rcritical
+// page-649-650
+clear;
+clc;
+// given
+f=50; // in Hz
+tq=62; // in us (Thyristor turn-off time)
+R=5; // in ohm
+I=1; // in A (let us assume this value for current source for calculation of load current)
+// calculate
+tq=tq*1E-6; // changing unit from us to s
+Toff=5*tq; // calculation of circuit turn-off time
+T=1/f; // calculation of time period
+// since Toff=0.69*R*C, therefore we get
+C=Toff/(0.69*R); // calculation of commutating capacitor
+I1=I*((1-exp(-T/(2*R*C)))/(1+exp(-T/(2*R*C)))); // calculation of load current
+Toff_critical=1.5*tq; // calculation of critical circuit turn-off time
+// since Toff=R*C*log(2/(1+exp(-T/(2*R*C)))), therefore we get
+Tcritical=2*R*C*log(2/(exp(Toff_critical/(R*C))-1)); // calculation of critical time period
+Fcritical=1/Tcritical; // calculation of critical frequency
+// since Toff=0.69*R*C, therefore we get
+Rcritical=Toff_critical/(0.69*C); // calculation of critical resistance
+printf("\nThe commutating capacitor is \t C=%.2f uF",C*1E6);
+printf("\nThe load current is \t\t I1=I=%.f A",I1);
+printf("\nThe critical frequency is \t Fcritical=%.1f Hz",Fcritical);
+printf("\nThe critical resistance is \t Rcritical=%.2f ohm",Rcritical);
+// Note: 1.The answer varies slightly as from calculated from the book due to precise calculation.
+//       2. for calculating other variables, author has use standard value of C (100 uF) for further calculation but I have used the value which is calculated.
\ No newline at end of file
diff --git a/3311/CH9/EX9.28/Ex9_28.sce b/3311/CH9/EX9.28/Ex9_28.sce
new file mode 100755
index 000000000..185a1af6c
--- /dev/null
+++ b/3311/CH9/EX9.28/Ex9_28.sce
@@ -0,0 +1,27 @@
+// chapter 9
+// example 9.28
+// Design an OTT-filter
+// page-662
+clear;
+clc;
+// given
+E_L=230; // in V (output voltage)
+f=50; // in Hz
+I_L=1.5; // in A (load current)
+Edc=40; // in V (source voltage)
+// calculate
+W_D=2*%pi*f; // calculation of design radian frequency
+Z_L=E_L/I_L; // calculation of load impedence
+Z_D=abs(Z_L)/2; // calculation of filter design impedence
+C1=1/(6*Z_D*W_D); // calculation of capacitance C1
+C2=1/(3*Z_D*W_D); // calculation of capacitance C2
+L1=9*Z_D/(2*W_D); // calculation of inductance L1
+L2=Z_D/W_D; // calculation of inductance L1
+printf("\nThe design radian frequency is \t W_D=%.f rad/s",W_D);
+printf("\nThe load impedence is \t\t Z_L=%.2f ohm",Z_L);
+printf("\nThe filter design impedence is \t Z_D=%.2f ohm",Z_D);
+printf("\nThe capacitance C1 is \t\t C1=%.2f uF",C1*1E6);
+printf("\nThe capacitance C2 is \t\t C2=%.2f uF",C2*1E6);
+printf("\nThe capacitance L1 is \t\t L1=%.3f H",L1);
+printf("\nThe capacitance L2 is \t\t L1=%.3f H",L2);
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH9/EX9.29/Ex9_29.sce b/3311/CH9/EX9.29/Ex9_29.sce
new file mode 100755
index 000000000..92a1b1941
--- /dev/null
+++ b/3311/CH9/EX9.29/Ex9_29.sce
@@ -0,0 +1,61 @@
+// chapter 9
+// example 9.29
+// Design a 400 Hz parallel invertor
+// page-663-664
+clear;
+clc;
+// given
+P0=360; // in W (output power)
+E_L=120; // in V (output voltage)
+f=400; // in Hz
+PF=0.7; // (lagging) (power factor)
+Edc=28; // in V (source voltage)
+Zin=80-23*%i; // filter input impedence (assumption as done in the book)
+neta=85; // in percent (assumption as done in the book)
+Toff=12; // in us (assumption for circuit turn-off time as done in the book)
+Ip_SCR=14; // in A (assumption for SCR peak current as done in the book)
+// calculate
+R_L=E_L^2*PF^2/P0; // calculation of load resistance
+X_L=(R_L/PF)*sqrt(1-PF^2); // calculation of load reactance
+Z_L_magnitude=sqrt(R_L^2+X_L^2); // calculation of load impedence
+Z_L_phase=acosd(PF); // calculation of load impedence phase
+Z_D=abs(Z_L_magnitude)/2; // calculation of filter design impedence
+W_D=2*%pi*f; // calculation of dsign radian frequency
+C1=1/(6*Z_D*W_D); // calculation of capacitance C1
+C2=1/(3*Z_D*W_D); // calculation of capacitance C2
+L1=9*Z_D/(2*W_D); // calculation of inductance L1
+L2=Z_D/W_D; // calculation of inductance L1
+Rin=real(Zin); // calculation of filter input resistance
+Xin=abs(imag(Zin)); // calculation of filter input reactance
+Zin_magnitude=abs(Zin); // calculation of filter input impedence magnitude
+E_SQ=(sqrt(2)/4)*%pi*Zin_magnitude*(P0/Rin)^0.5 // calculation of input voltage to filter
+n=E_SQ/Edc; // calculation of transfromer turns ratio
+Pi=P0/(neta/100); // calculation of input power
+I_T_av=P0*Zin_magnitude/(2*Edc*Rin); // calculation of average thyristor current
+V_BO=2.5*Edc; // calculation of blocking voltage
+L=6*Edc*Toff/(%pi*Ip_SCR); // calculation of commutating inductance
+C=3*Toff*Ip_SCR/(8*%pi*Edc); // calculation of commutating capacitance
+di_dt=2*Edc/L; // calculation of rate of change of current
+printf("\nThe load resistance is \t\t\t\t R_L=%.f ohm",R_L);
+printf("\nThe load reactance is \t\t\t\t X_L=%.f ohm",X_L);
+printf("\nThe magnitude of load impedence is \t\t Z_L_magnitude=%.1f ohm",Z_L_magnitude);
+printf("\nThe phase of load impedence is \t\t\t Z_L_phase=%.f degree",Z_L_phase);
+printf("\nThe filter design impedence is \t\t\t Z_D=%.2f ohm",Z_D);
+printf("\nThe design radian frequency is \t\t\t W_D=%.f rad/s",W_D);
+printf("\nThe capacitance C1 is \t\t\t\t C1=%.1f uF",C1*1E6);
+printf("\nThe capacitance C2 is \t\t\t\t C2=%.1f uF",C2*1E6);
+printf("\nThe capacitance L1 is \t\t\t\t L1=%.1f mH",L1*1E3);
+printf("\nThe capacitance L2 is \t\t\t\t L1=%.f mH",L2*1E3);
+printf("\nThe filter input resistance is \t\t\t Rin=%.f ohm",Rin);
+printf("\nThe filter input reactance is \t\t\t Xin=%.f ohm",Xin);
+printf("\nThe magnitude of filter input impedence is \t Zin_magnitude=%.f ohm",Zin_magnitude);
+printf("\nThe input voltage to filter is \t\t\t E_SQ=%.f V",E_SQ);
+printf("\nThe transfromer turns ratio is \t\t\t n=%.f",n);
+printf("\nThe input power is \t\t\t\t Pin=%.f W",Pi);
+printf("\nThe verage thyristor current is \t\t I_T_av=%.1f A",I_T_av);
+printf("\nThe blocking voltage is \t\t\t V_BO=%.f V",V_BO);
+printf("\nThe commutating inductance is \t\t\t L=%.1f uH",L);
+printf("\nThe commutating capacitance is \t\t\t C=%.2f uF",C);
+printf("\nThe rate of change of current at t=0 s is \t di/dt=%.2f A/us",di_dt);
+// Note: 1. The answer varies slightly due to precise calculation.
+//       2. Most of the answers have been rounded off in the book and then used for further calculation. I have used the exact values for the calculations
\ No newline at end of file
diff --git a/3311/CH9/EX9.3/Ex9_3.sce b/3311/CH9/EX9.3/Ex9_3.sce
new file mode 100755
index 000000000..eb74d5c7c
--- /dev/null
+++ b/3311/CH9/EX9.3/Ex9_3.sce
@@ -0,0 +1,35 @@
+// chapter 9
+// example 9.3
+// fig. 9.5
+// Determine rms load current at fundamental frequency, rms value of load current, power output and average supply current
+// page-550
+clear;
+clc;
+// given
+Edc=220; // in V (dc source)
+R=10; // in ohm
+L=10; // in mH
+C=52; // in uF
+f=400; // in Hz
+// calculate
+L=L*1E-3; // changing unit from mH to H
+C=C*1E-6; // changing unit from uF to F
+X_L=2*%pi*f*L; // calculation of inductive reactance
+X_C=1/(2*%pi*f*C); // calculation of inductive reactance
+I=0; // intialisation of variable for rms load current
+// since Impedence offered to the nth harmonic component Zn=sqrt(R^2+(n*X_L-X_C/n)^2)
+printf("\nn\t\tZn\t\t\tIn");
+for n=1:2:9
+    Zn=sqrt(R^2+(n*X_L-X_C/n)^2); // calculation of Impedence offered to the nth harmonic component
+    En=0.9*Edc/n; // calculation of rms value of the nth harmonic component of the output voltage
+    In=En/Zn; // calculation of rms value of nth harmonic component of the current
+    printf("\n%.f\t\t%.2f ohm\t\t%.3f A",n,Zn,In);
+    I=I+In^2;
+end
+I=sqrt(I);
+printf("\n\nThe rms value of load current is \t I=%.2f A",I);
+P0=I^2*R; // calculation of output power
+Iav=P0/Edc; // calculation of average supply current
+printf("\n\nThe output power is \t\t\t P0=%.2f W",P0);
+printf("\n\nThe average supply current is \t\t Iav=%.2f A",Iav);
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH9/EX9.4/Ex9_4.sce b/3311/CH9/EX9.4/Ex9_4.sce
new file mode 100755
index 000000000..c716cb144
--- /dev/null
+++ b/3311/CH9/EX9.4/Ex9_4.sce
@@ -0,0 +1,33 @@
+// chapter 9
+// example 9.4
+// fig. 9.5
+// Determine IGBT ratings, THD, DF and HF and DF of the lowest order harmonic
+// page-552-554
+clear;
+clc;
+// given
+Edc=24; // in V (dc source)
+R=3; // in ohm
+// calculate
+I_peak=(Edc/2)/R; // calculation of IGBT peak current
+V_BR=2*(Edc/2); // calculation of peak reverse voltage of each IGBT
+printf("\nThe IGBT ratings are \t I_peak=%.f A \t V_BR=%.f V",I_peak,V_BR);
+E1_rms=2*Edc/(sqrt(2)*%pi);
+E0_rms=(Edc/2);
+THD=sqrt(E0_rms^2-E1_rms^2)/E1_rms; // calculation of total harmonic distortion
+printf("\nThe total harmonic distortion is \t THD=%.3f or \t %.1f percent",THD,THD*100);
+K=0;
+for n=3:2:13
+    En_rms=2*Edc/(n*%pi*sqrt(2));
+    En_rms_n2=(En_rms/n^2)^2;
+    K=K+En_rms_n2;
+end
+K=sqrt(K);
+DF=K/E1_rms; // calculation of distortion factor
+printf("\nThe distortion factor is \t\t DF=%.3f or \t %.1f percent",DF,DF*100);
+E3_rms=2*Edc/(3*%pi*sqrt(2));
+HF3=E3_rms/E1_rms; // calculation of lowest order of harmonic distortion
+printf("\nThe lowest order harmonic factor is \t HF3=%.3f or \t %.2f percent",HF3,HF3*100);
+DF3=(E3_rms/3^2)/E1_rms; // calculation of lowest order distortion factor
+printf("\nThe lowest order distortion factor is \t DF3=%.3f or \t %.2f percent",DF3,DF3*100);
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH9/EX9.5/Ex9_5.sce b/3311/CH9/EX9.5/Ex9_5.sce
new file mode 100755
index 000000000..2f841e2fc
--- /dev/null
+++ b/3311/CH9/EX9.5/Ex9_5.sce
@@ -0,0 +1,33 @@
+// chapter 9
+// example 9.5
+// Determine transistor ratings, THD, DF and HF and DF of the lowest order harmonic
+// page-554
+clear;
+clc;
+// given
+Edc=48; // in V (dc source)
+R=3; // in ohm
+// calculate
+Ip=Edc/R; // calculation of transistor peak current
+I_avg=Ip/2; // calculation of transistor average current
+V_BR=Edc; // calculation of peak reverse voltage of each IGBT
+printf("\nThe transistor ratings are \t Ip=%.f A \t I_avg=%.f A \t V_BR=%.f V",Ip,I_avg,V_BR);
+E1_rms=2*Edc/(sqrt(2)*%pi);
+E0_rms=(Edc/2);
+THD=sqrt(E0_rms^2-E1_rms^2)/E1_rms; // calculation of total harmonic distortion
+printf("\nThe total harmonic distortion is \t THD=%.3f or \t %.1f percent",THD,THD*100);
+K=0;
+for n=3:2:13
+    En_rms=2*Edc/(n*%pi*sqrt(2));
+    En_rms_n2=(En_rms/n^2)^2;
+    K=K+En_rms_n2;
+end
+K=sqrt(K);
+DF=K/E1_rms; // calculation of distortion factor
+printf("\n\nThe distortion factor is \t\t DF=%.3f   or   \t %.1f percent",DF,DF*100);
+E3_rms=2*Edc/(3*%pi*sqrt(2));
+HF3=E3_rms/E1_rms; // calculation of lowest order of harmonic distortion
+printf("\n\nThe lowest order harmonic factor is \t HF3=%.3f   or   \t %.2f percent",HF3,HF3*100);
+DF3=(E3_rms/3^2)/E1_rms; // calculation of lowest order distortion factor
+printf("\n\nThe lowest order distortion factor is \t DF3=%.4f   or   \t %.3f percent",DF3,DF3*100);
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH9/EX9.6/Ex9_6.sce b/3311/CH9/EX9.6/Ex9_6.sce
new file mode 100755
index 000000000..1f9ac0474
--- /dev/null
+++ b/3311/CH9/EX9.6/Ex9_6.sce
@@ -0,0 +1,56 @@
+// chapter 9
+// example 9.6
+// Determine carrier ratio and the number of pulses per cycle, Fundamental output voltage, DF and HF of the output voltage and the order of first five significant harmonics
+// page-569-570
+clear;
+clc;
+// given
+Edc_2=240; // in V (dc source)
+fm=50; // in Hz (fundamental output frequency)
+fc=1.2; // in KHz (carrier frequency)
+M=0.8; // modulation index
+// calculate
+fc=fc*1E3;
+Mf=fc/fm; // calculation of carrier ratio
+p=Mf; // calculation of number of pulses per cycle
+E0_fund=(1/sqrt(2))*M*Edc_2; // calculation of Fundamental output voltage
+E0_rms=Edc_2;
+DF=E0_fund/E0_rms; // calculation of DF of the output voltage
+HF=sqrt(1/DF^2-1); // calculation of HF of the output voltage
+printf("\nThe carrier ratio is \t\t\t\t Mf=%.f",Mf);
+printf("\nThe number of pulses per cycle is \t\t p=%.f",p);
+printf("\nThe distortion factor of the output voltage is \t DF=%.2f percent",DF*100);
+printf("\nThe harmonic factor of the output voltage is \t HF=%.1f percent",HF*100);
+printf("\n\n The order of first five harmonics are \n\nn=");
+for n=0:2:2
+    N1=Mf-n;
+    N2=Mf+n;
+    printf("%.f, %.f, ",N1,N2);
+end
+printf(" etc\n\nn=");
+for n=1:2:3
+    N1=2*Mf-n;
+    N2=2*Mf+n;
+    printf("%.f, %.f, ",N1,N2);
+end
+printf(" etc\n\nn=");
+for n=0:2:2
+    N1=3*Mf-n;
+    N2=3*Mf+n;
+    printf("%.f, %.f, ",N1,N2);
+end
+printf(" etc\n\nn=");
+for n=1:2:3
+    N1=4*Mf-n;
+    N2=4*Mf+n;
+    printf("%.f, %.f, ",N1,N2);
+end
+printf(" etc\n\nn=");
+for n=0:2:4
+    N1=5*Mf-n;
+    N2=5*Mf+n;
+    printf("%.f, %.f, ",N1,N2);
+end
+printf(" etc");
+// Note: 1. The answer varies slightly due to precise calculation
+//       2. The calculation of order of first five significant harmonics is wrong in the book due to calculation mistake
\ No newline at end of file
diff --git a/3311/CH9/EX9.7/Ex9_7.sce b/3311/CH9/EX9.7/Ex9_7.sce
new file mode 100755
index 000000000..9fd86cde9
--- /dev/null
+++ b/3311/CH9/EX9.7/Ex9_7.sce
@@ -0,0 +1,16 @@
+// chapter 9
+// example 9.7
+// Compute DC and switch voltage ratings
+// page-570
+clear;
+clc;
+// given
+E0_rms=220; // in V (Fundamental output voltage)
+M=0.8; // modulation index
+// calculate
+// since E0_rms=sqrt(1/2)*M*(Edc_2), therefore we get
+Edc_2=E0_rms/(sqrt(1/2)*M); // calculation of DC voltage ratings
+V_CEO=2*Edc_2; // calculation of switch voltage ratings
+printf("\nThe DC voltage ratings is \t %.2f V",Edc_2);
+printf("\nThe switch voltage ratings is \t %.f V",V_CEO);
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH9/EX9.8/Ex9_8.sce b/3311/CH9/EX9.8/Ex9_8.sce
new file mode 100755
index 000000000..452fb604f
--- /dev/null
+++ b/3311/CH9/EX9.8/Ex9_8.sce
@@ -0,0 +1,22 @@
+// chapter 9
+// example 9.8
+// Compute Total rms output voltage, fundamental output voltage, DF and HF and gain of the invertor
+// page-572
+clear;
+clc;
+// given
+Edc=240; // in V (battery voltage)
+M=0.8; // modulation index
+// calculate
+E0_rms=Edc; // calculation of rms output voltage
+E0_fund=M*Edc/sqrt(2); // calculation of Fundamental output voltage
+DF=M/sqrt(2); // calculation of distortion factor
+HF=sqrt(2/M^2-1); // calculation of harmonic factor
+G=M/sqrt(2); // calculation of gain of the invertor
+
+printf("\nThe rms output voltage is \t\t E0_rms=%.f V",E0_rms);
+printf("\nThe Fundamental output voltage is \t E0_fund=%.f V",E0_fund);
+printf("\nThe distortion factor is \t\t DF=%.4f ",DF);
+printf("\nThe harmonic factor is \t\t\t HF=%.3f ",HF);
+printf("\nThe gain of the invertor is \t\t G=%.4f ",G);
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file
diff --git a/3311/CH9/EX9.9/Ex9_9.sce b/3311/CH9/EX9.9/Ex9_9.sce
new file mode 100755
index 000000000..d19fad1ba
--- /dev/null
+++ b/3311/CH9/EX9.9/Ex9_9.sce
@@ -0,0 +1,16 @@
+// chapter 9
+// example 9.9
+// What should be te amplitude of modulation index
+// page-572
+clear;
+clc;
+// given
+Edc=120; // in V (battery voltage)
+K=1/3; // transformer turn ratio
+E01_rms=210; // in V (Fundamental output voltage of secondary)
+// calculate
+E0_fund=E01_rms*K; // calculation of Fundamental voltage component at primary of the transformer
+// since E0_fund=M*Edc/sqrt(2), therefore we get
+M=E0_fund*sqrt(2)/Edc; // calculation of amplitude of modulation index
+printf("\nThe amplitude of modulation index is \t M=%.2f",M);
+// Note: The answer varies slightly due to precise calculation
\ No newline at end of file