initial commit / add all books

46 files changed, 967 insertions, 0 deletions

diff --git a/3775/CH2/EX2.1/Ex2_1.sce b/3775/CH2/EX2.1/Ex2_1.sce
new file mode 100644
index 000000000..994b2525e
--- /dev/null
+++ b/3775/CH2/EX2.1/Ex2_1.sce
@@ -0,0 +1,15 @@
+//Ex 2.1 page 67
+
+clc;
+clear;
+close;
+
+V1=1;//V across SCR
+IG=0;//A
+Ih=2;//mA holding current
+R=50;//ohm
+
+// Applying kirchoff law
+//VA-(IAK*R)-V1=0
+VA=(Ih*10**-3*R)+V1;//V (let IAK=Ih)
+printf('VA = %.2f V',VA)
diff --git a/3775/CH2/EX2.10/Ex2_10.sce b/3775/CH2/EX2.10/Ex2_10.sce
new file mode 100644
index 000000000..d2ef39989
--- /dev/null
+++ b/3775/CH2/EX2.10/Ex2_10.sce
@@ -0,0 +1,17 @@
+//Ex 2.10 page 73
+
+clc;
+clear;
+close;
+
+R=10;// ohm
+L=0.1;// H
+delta_i=20/1000;// A
+Vs=230;// V4
+f=50;// Hz
+theta=45;//degree
+
+delta_t = L*delta_i/Vs; // s
+delta_t = delta_t*10**6;// micro s
+printf('Minimum gate pulse width = %.1f micro s',delta_t)
+
diff --git a/3775/CH2/EX2.11/Ex2_11.sce b/3775/CH2/EX2.11/Ex2_11.sce
new file mode 100644
index 000000000..80b0ca754
--- /dev/null
+++ b/3775/CH2/EX2.11/Ex2_11.sce
@@ -0,0 +1,15 @@
+//Ex 2.11 page 73
+
+clc;
+clear;
+close;
+
+m=3*10**3;// gradient (VG/IG)
+VS=10;// V
+PG=0.012;// W
+// IG = VG/m & PG=VG*IG
+VG=sqrt(PG*m)
+IG=VG/m ; // A
+RS=(VS-VG)/IG/1000;// kohm
+printf('gate source resistance = %.1f kohm',RS)
+
diff --git a/3775/CH2/EX2.12/Ex2_12.sce b/3775/CH2/EX2.12/Ex2_12.sce
new file mode 100644
index 000000000..4d3d55c5c
--- /dev/null
+++ b/3775/CH2/EX2.12/Ex2_12.sce
@@ -0,0 +1,19 @@
+//Ex 2.12 page 74
+
+clc;
+clear;
+close;
+
+VS=300;// V
+delta_i = 50/1000;// A
+R=60;// ohm
+L=2;// H
+TP=40*10**-6;// s
+
+I1=VS/L*TP;// A (at the end of pulse)
+// as I1 << delta_i
+I2=delta_i;// A (anode current with RL load)
+
+Rdash = VS/(I2-I1)/1000;// kohm
+printf('Value of resistance = %.2f kohm',Rdash)
+
diff --git a/3775/CH2/EX2.13/Ex2_13.sce b/3775/CH2/EX2.13/Ex2_13.sce
new file mode 100644
index 000000000..f329cd717
--- /dev/null
+++ b/3775/CH2/EX2.13/Ex2_13.sce
@@ -0,0 +1,57 @@
+//Ex 2.13 page 74
+
+clc;
+clear;
+close;
+
+Im=50;// A
+
+printf('For half sine wave current : \n')
+// theta=180;// degree
+theta=180;// degree
+Iav=Im/%pi;// A
+Irms=Im/2;// A
+FF=Irms/Iav;// form factor
+ITav=Im/FF ; // A
+printf('(i) Average ON State current  = %.2f A\n',ITav)    
+
+// theta=90;// degree
+theta=90;// degree
+Iav=Im/2/%pi;// A
+Irms=Im/2/sqrt(2);// A
+FF=Irms/Iav;// form factor
+ITav=Im/FF ; // A
+printf('(ii) Average ON State current  = %.2f A\n',ITav)    
+
+// theta=180;// degree
+theta=180;// degree
+Iav=Im*0.0213;// A
+Irms=Im*0.0849;// A
+FF=Irms/Iav;// form factor
+ITav=Im/FF ; // A
+printf('(iii) Average ON State current  = %.2f A\n',ITav)    
+
+printf('\n For rectangular wave current : \n')
+// theta=180;// degree
+theta=180;// degree
+Iav=Im/2;// A
+Irms=Im/sqrt(2);// A
+FF=Irms/Iav;// form factor
+ITav=Im/FF ; // A
+printf('(i) Average ON State current  = %.2f A\n',ITav)    
+
+// theta=90;// degree
+theta=90;// degree
+Iav=Im/4;// A
+Irms=Im/2;// A
+FF=Irms/Iav;// form factor
+ITav=Im/FF ; // A
+printf('(ii) Average ON State current  = %.2f A\n',ITav)    
+
+// theta=180;// degree
+theta=180;// degree
+Iav=Im/12;// A
+Irms=Im/2/sqrt(3);// A
+FF=Irms/Iav;// form factor
+ITav=Im/FF ; // A
+printf('(i) Average ON State current  = %.2f A\n',ITav)    
diff --git a/3775/CH2/EX2.14/Ex2_14.sce b/3775/CH2/EX2.14/Ex2_14.sce
new file mode 100644
index 000000000..62a65af10
--- /dev/null
+++ b/3775/CH2/EX2.14/Ex2_14.sce
@@ -0,0 +1,41 @@
+//Ex 2.14 page 76
+
+clc;
+clear;
+close;
+
+VS=500;// V
+IP=250;// A
+diBYdt=60;// A/micro-s
+dvaBYdt=200;// V/micro-s
+RL=20;// ohm
+r=0.65;// ohm
+eps=0.65 ;// damping ratio
+
+F=2;// saftety factor
+IP=IP/2;// A
+diBYdt=60/2;// A/micro-s
+dvaBYdt=200/2;// V/micro-s
+L=VS/diBYdt;// uH
+R=L*10**6/VS*dvaBYdt/10**6;// ohm
+printf('Value of L = %.2f uH',L)
+printf('\n Value of R = %.1f ohm',R)
+
+Ip=VS/RL+VS/R;// A
+if Ip > IP then
+    printf('\n Value of Ip = %.1f A is greater than permissible peak current = %.1f A\n change the value of Rs',Ip,IP)
+    Rs=6;//ohm
+end
+Ip=VS/RL+VS/Rs;// A
+Cs=(2*eps/Rs)**2*L;// micro F
+printf('\n Value of C = %.2f micro F',Cs)
+
+//load combination current Cs*dv/dt = Vs/(Rs+RL)
+
+Cs=0.4;// uF (reduced value of Cs)
+Rs=6;//ohm
+dvBYdt = VS/(Rs+RL)/Cs; // V/micro-s
+printf('\n Value of dv/dt = %.1f V micro-s',dvBYdt)
+disp('This is less than the specified max. value. Hence the choice is correct.')
+
+//Answer in the textbook is wrong. In last part RL+Rs = 18 is taken in place of 26
diff --git a/3775/CH2/EX2.15/Ex2_15.sce b/3775/CH2/EX2.15/Ex2_15.sce
new file mode 100644
index 000000000..3288a0a68
--- /dev/null
+++ b/3775/CH2/EX2.15/Ex2_15.sce
@@ -0,0 +1,12 @@
+//Ex 2.15 page 77
+
+clc;
+clear;
+close;
+
+Isb=3000;// A
+f=50;// Hz
+I=sqrt((Isb**2*1/2/f)*f) ;// A
+I2t=I**2/2/f;// sq.A/s
+printf('I2t rating = %d A**2/s',ceil(I2t))
+
diff --git a/3775/CH2/EX2.2/Ex2_2.sce b/3775/CH2/EX2.2/Ex2_2.sce
new file mode 100644
index 000000000..81ea2e9af
--- /dev/null
+++ b/3775/CH2/EX2.2/Ex2_2.sce
@@ -0,0 +1,10 @@
+//Ex 2.2 page 67
+
+clc;
+clear;
+close;
+
+diBYdt=1000;//A/s (rate of rise of current)
+il=10;//mA (latching current = diBYdt * tp)
+tp=il*10**-3/diBYdt;//s
+printf('Minimum duration of gating pulse = %.f micro s',tp*10**6)
diff --git a/3775/CH2/EX2.3/Ex2_3.sce b/3775/CH2/EX2.3/Ex2_3.sce
new file mode 100644
index 000000000..c0ac9e02f
--- /dev/null
+++ b/3775/CH2/EX2.3/Ex2_3.sce
@@ -0,0 +1,18 @@
+//Ex 2.3 page 68
+
+clc;
+clear;
+close;
+
+m=16;// V/A (gradient)
+t_on=4;// us
+IG=500;// mA
+VS=15;// V
+
+VG=m*IG/1000;// V
+//Load line equation
+//VG=VS-IG*RS
+RS=(VS-VG)/(IG/1000) ;// ohm
+Pg=VS*(IG/1000)**2 ; // W
+printf('Gate power dissipation = %.f W',Pg)
+printf('\n Resistance to be connected = %.f ohm',RS)
diff --git a/3775/CH2/EX2.4/Ex2_4.sce b/3775/CH2/EX2.4/Ex2_4.sce
new file mode 100644
index 000000000..949b80064
--- /dev/null
+++ b/3775/CH2/EX2.4/Ex2_4.sce
@@ -0,0 +1,23 @@
+//Ex 2.4 page 68
+
+clc;
+clear;
+close;
+
+// VG=0.5+8*IG -- eqn(1)
+f=400; // Hz
+delta=0.1 ; // (Duty Cycle)
+P=0.5;//W
+VS=12;// V
+
+Tp=1/f*10**6;// us
+// P= VG*IG -- eqn(2)
+// solving eqn  1 and 2
+//8*IG*IG**2+0.5*IG-P=0
+p=[8, 0.5, -P] // polynomial for IG
+IG=roots(p) ;// A 
+IG=IG(2) ;// A (discarding -ve value)
+VG=0.5+8*IG;// V
+// VS=VG+IG*RS
+RS=(VS-VG)/IG
+printf('Value of resistance to be added in series = %.2f ohm',RS)
diff --git a/3775/CH2/EX2.5/Ex2_5.sce b/3775/CH2/EX2.5/Ex2_5.sce
new file mode 100644
index 000000000..c3511c44a
--- /dev/null
+++ b/3775/CH2/EX2.5/Ex2_5.sce
@@ -0,0 +1,23 @@
+//Ex 2.5 page 69
+
+clc;
+clear;
+close;
+
+// VG=10*IG -- eqn(1)
+PGM=5;// W
+PGav=.5;// W
+VS=12;// V
+Tp=20;// us
+
+// PGM = VG*IG where VG=10*IG
+IG=sqrt(PGM/10);// A
+VG=10*IG;// V
+// During the application of pulse VS = VG+(IG*RS)
+RS=(VS-VG)/IG ;// ohm
+f=PGav/(PGM*Tp*10**-6)/1000;// kHz
+delta=f*1000*Tp*10**-6;// Duty Cycle
+printf('Value of resistance to be connected in series = %.2f ohm',RS)
+printf('\n Triggering frequency = %.2f kHz',f)
+printf('\n Duty Cycle = %.1f ',delta)
+// Note : ans in the textbook is not accurate.
diff --git a/3775/CH2/EX2.6/Ex2_6.sce b/3775/CH2/EX2.6/Ex2_6.sce
new file mode 100644
index 000000000..7da826e21
--- /dev/null
+++ b/3775/CH2/EX2.6/Ex2_6.sce
@@ -0,0 +1,21 @@
+//Ex 2.6 page 70
+
+clc;
+clear;
+close;
+
+VS=3;// kV
+IS=750;// A
+
+VD=800;// V
+ID=175;// A
+dr=30/100;// de-rating factor
+IB=8;//mA
+delQ=30;// u Coulomb
+// dr = 1-IS/np*ID
+np = round(IS/(1-dr)/(ID)) ; // no. of parallel string
+ns = round(VS*1000/(1-dr)/(VD)) ; // no. of series string
+R=(ns*VD-VS*1000)/(ns-1)/(IB/1000)/1000;//kohm
+C=(ns-1)*delQ*10**-6/(ns*VD-VS*1000)
+printf('Value of R = %.2f kohm',R)
+printf('\n Value of C = %.2e F',C)
diff --git a/3775/CH2/EX2.7/Ex2_7.sce b/3775/CH2/EX2.7/Ex2_7.sce
new file mode 100644
index 000000000..517db0b76
--- /dev/null
+++ b/3775/CH2/EX2.7/Ex2_7.sce
@@ -0,0 +1,19 @@
+//Ex 2.7 page 71
+
+clc;
+clear;
+close;
+
+VS=4;// kV
+IS=800;// A
+
+VD=800;// V
+ID=200;// A
+dr=20/100;// de-rating factor
+// for series connection
+ns = ceil(VS*1000/(1-dr)/(VD)) ; // no. of series string
+// for parallel connection
+np = round(IS/(1-dr)/(ID)) ; // no. of parallel string
+printf('\n no. of series connection = %d',ns)
+printf('\n no. of parallel connection = %d',np)
+
diff --git a/3775/CH2/EX2.8/Ex2_8.sce b/3775/CH2/EX2.8/Ex2_8.sce
new file mode 100644
index 000000000..e8f53b605
--- /dev/null
+++ b/3775/CH2/EX2.8/Ex2_8.sce
@@ -0,0 +1,19 @@
+//Ex 2.8 page 72
+
+clc;
+clear;
+close;
+
+IS1=100;// A
+IS2=150;// A
+vd1=2.1;// V
+vd2=1.75;// V
+I=250;// A
+
+rf1=vd1/IS1;// ohm
+rf2=vd2/IS2;// ohm
+// Equating voltage drops
+// vd1+IS1*re = vd2+IS2*re
+re=(vd1-vd2)/(IS2-IS1)
+printf(' Series resistance = %.3f ohm',re)
+
diff --git a/3775/CH2/EX2.9/Ex2_9.sce b/3775/CH2/EX2.9/Ex2_9.sce
new file mode 100644
index 000000000..2ae72759f
--- /dev/null
+++ b/3775/CH2/EX2.9/Ex2_9.sce
@@ -0,0 +1,17 @@
+//Ex 2.9 page 72
+
+clc;
+clear;
+close;
+
+Vf1=1;// V
+If1=0;//A
+Vf2=1.9;// V
+If2=60;//A
+IT=20*%pi;// A
+// PAV = 1/T*integrate(VT*IT,0,T)*dt = ITAV+0.015*IRMS**2
+ITAV=IT/%pi;//A
+ITRMS=IT/2;// A
+dt=ITAV+0.015*ITRMS**2;// W
+printf('Average power loss = %.1f W',dt)
+
diff --git a/3775/CH3/EX3.1/Ex3_1.sce b/3775/CH3/EX3.1/Ex3_1.sce
new file mode 100644
index 000000000..a019e6bf9
--- /dev/null
+++ b/3775/CH3/EX3.1/Ex3_1.sce
@@ -0,0 +1,20 @@
+//Ex 3.1 page 117
+
+clc;
+clear;
+close;
+
+R=100;// ohm
+Vs=230;// V
+f=50;// Hz
+alpha=45;// degree
+
+Vo=Vs*sqrt(2)/2/%pi*(1+cosd(alpha));// V
+Io=Vo/R;// A
+printf('Average current = %.4f A',Io)
+Vor=Vs/sqrt(2)*sqrt(1/180*((180-alpha)+sind(2*alpha)/2));// V
+Ior=Vor/R;// A
+P=Ior**2*R;// W
+printf('\n Power delivered = %.2f W',P)
+
+//Ans in the textbook is not accurate.
diff --git a/3775/CH3/EX3.10/Ex3_10.sce b/3775/CH3/EX3.10/Ex3_10.sce
new file mode 100644
index 000000000..ee08c1c16
--- /dev/null
+++ b/3775/CH3/EX3.10/Ex3_10.sce
@@ -0,0 +1,15 @@
+//Ex 3.10 page 124
+
+clc;
+clear;
+close;
+
+R=2;// ohm
+Vs=230;// V
+f=50;// Hz
+alpha = 120;// degree
+Ia=10;// A
+
+Vo=2*sqrt(2)*Vs*cos(alpha*%pi/180)/%pi
+V=Ia*R-Vo;// V
+printf('emf on load side = %.2f V', V)
diff --git a/3775/CH3/EX3.11/Ex3_11.sce b/3775/CH3/EX3.11/Ex3_11.sce
new file mode 100644
index 000000000..84a4ec0d9
--- /dev/null
+++ b/3775/CH3/EX3.11/Ex3_11.sce
@@ -0,0 +1,30 @@
+//Ex 3.11 page 125
+
+clc;
+clear;
+close;
+
+Vs=230;// V
+Io=5;// A
+alpha = 45;// degree
+printf('part(i)')
+Vo=2*sqrt(2)*Vs/%pi*cos(alpha*%pi/180);// V
+printf('\n dc output voltage = %.1f V',Vo)
+Pi=Vo*Io;// W
+printf('\n Active power = %.1f W',Pi)
+Qi=2*sqrt(2)*Vs/%pi*sin(alpha*%pi/180)*Io;// VAR
+printf('\n Reactive power = %.1f VAR',Qi)
+printf('\n\n part(ii)')
+R=Vo/Io;// ohm
+Vo=sqrt(2)*Vs/%pi*(1+cos(alpha*%pi/180));// V
+printf('\n dc output voltage = %.1f V',Vo)
+Io=Vo/R;// A
+Pi=Vo*Io;// W
+printf('\n Active power = %.1f W',Pi)
+Qi=sqrt(2)*Vs/%pi*sin(alpha*%pi/180)*Io;// VAR
+printf('\n Reactive power = %.0f VAR',Qi)
+printf('\n\n part(iii)')
+Vo=sqrt(2)*Vs/%pi/2*(1+cos(alpha*%pi/180));// 
+printf('\n Average load voltage = %.0f V',Vo)
+Io=Vo/R;// A
+printf('\n Average load current = %.2f A',Io)
diff --git a/3775/CH3/EX3.12/Ex3_12.sce b/3775/CH3/EX3.12/Ex3_12.sce
new file mode 100644
index 000000000..5b4acf18a
--- /dev/null
+++ b/3775/CH3/EX3.12/Ex3_12.sce
@@ -0,0 +1,16 @@
+//Ex 3.12 page 126
+
+clc;
+clear;
+close;
+
+R=20;// ohm
+Vs=400;// V
+f=50;// Hz
+alpha = 30;// degree
+
+Vm=Vs*sqrt(2);// V
+Vo=3*Vm/%pi*cos(alpha*%pi/180);// V
+Io=Vo/R;// A
+printf('\n Average load voltage = %.3f V',Vo)
+printf('\n Average load current = %.3f A',Io)
diff --git a/3775/CH3/EX3.13/Ex3_13.sce b/3775/CH3/EX3.13/Ex3_13.sce
new file mode 100644
index 000000000..0e8ffe356
--- /dev/null
+++ b/3775/CH3/EX3.13/Ex3_13.sce
@@ -0,0 +1,29 @@
+//Ex 3.13 page 126
+
+clc;
+clear;
+close;
+
+n=3;// no. of phase
+Vs=400;// V
+f=50;// Hz
+Io=100;// A
+alpha = 60;// degree
+
+Vm=Vs*sqrt(2);// V
+Vo=n*Vm/%pi*cos(alpha*%pi/180);// V
+Po=Vo*Io;// W
+printf(' (i)')
+printf('\n Output voltage = %.0f V',Vo)
+printf('\n Output power = %.0f W',Po)
+printf('\n\n (ii)')
+Iav=Io*2*%pi/3/2/%pi;// A
+printf('\n average current through thyristor = %.2f A', Iav)
+Ior=sqrt(Io**2*2*%pi/3/2/%pi);// A
+printf('\n rms current through thyristor = %.2f A', Ior)
+Ip=Io;//A
+printf('\n peak current through thyristor = %.2f A', Ip)
+printf('\n\n (iii)')
+PIV=sqrt(2)*Vs;//V
+printf('\n PIV of thyristor = %.1f V',PIV)
+// Ans in the book is not accurate.
diff --git a/3775/CH3/EX3.14/Ex3_14.sce b/3775/CH3/EX3.14/Ex3_14.sce
new file mode 100644
index 000000000..5083948a6
--- /dev/null
+++ b/3775/CH3/EX3.14/Ex3_14.sce
@@ -0,0 +1,22 @@
+//Ex 3.14 page 127
+
+clc;
+clear;
+close;
+
+n=3;// no. of phase
+R=60;// ohm
+Vs=400;// V
+alpha = 30;// degree
+
+Vm=Vs*sqrt(2);// V
+Vo=3*Vm/%pi*cos(alpha*%pi/180);// V
+Io=Vo/R;// A
+Is=Io*sqrt(2/3);// A
+P=Io**2*R;// W
+pf=P/sqrt(3)/Vs/Is;// power factor
+
+printf('\n Average load voltage = %.3f V',Vo)
+printf('\n Average load current = %.1f A',Io)
+printf('\n input power factor = %.4f',pf)
+// Note : Ans in the textbook is wrong as in calculation for pf Io is used in place of Is
diff --git a/3775/CH3/EX3.15/Ex3_15.sce b/3775/CH3/EX3.15/Ex3_15.sce
new file mode 100644
index 000000000..67dfdc114
--- /dev/null
+++ b/3775/CH3/EX3.15/Ex3_15.sce
@@ -0,0 +1,17 @@
+//Ex 3.15 page 127
+
+clc;
+clear;
+close;
+
+n=3;// no. of phase
+R=50;// ohm
+Vs=400;// V
+f=50;// Hz
+alpha = 45;// degree
+
+Vm=Vs*sqrt(2);// V
+Vo=3*Vm/2/%pi*(1+cos(alpha*%pi/180));// V
+Io=Vo/R;// A
+printf('\n Average load voltage = %.2f V',Vo)
+printf('\n Average load current = %.2f A',Io)
diff --git a/3775/CH3/EX3.16/Ex3_16.sce b/3775/CH3/EX3.16/Ex3_16.sce
new file mode 100644
index 000000000..c90eeaf75
--- /dev/null
+++ b/3775/CH3/EX3.16/Ex3_16.sce
@@ -0,0 +1,24 @@
+//Ex 3.16 page 128
+
+clc;
+clear;
+close;
+
+n=3;// no. of phase
+Vs=400;// V
+f=50;// Hz
+Ls=5/1000;// H
+Io=20;// A
+Ri=1;// ohm
+Vdc=400;// V
+
+Vo=Vdc+Io*Ri;// V
+// Vo=3*Vm/%pi*cos(alpha*%pi/180)-3*2*%pi*f*Ls/%pi*Io
+Vm=sqrt(2)*Vs;// V
+alpha=acos((Vo+3*2*%pi*f*Ls/%pi*Io)/(3*Vm/%pi))*180/%pi;// degree
+
+// Vo=3*Vm/%pi*cos((alpha+mu)*%pi/180)-3*2*%pi*f*Ls/%pi*Io
+mu=acos((Vo-3*2*%pi*f*Ls/%pi*Io)/(3*Vm/%pi))*180/%pi-alpha;// degree
+printf('\n Firing angle = %.2f degree',alpha)
+printf('\n Overlap angle = %.2f degree',mu)
+// ans in the textbook is not accurate.
diff --git a/3775/CH3/EX3.17/Ex3_17.sce b/3775/CH3/EX3.17/Ex3_17.sce
new file mode 100644
index 000000000..8986a5e79
--- /dev/null
+++ b/3775/CH3/EX3.17/Ex3_17.sce
@@ -0,0 +1,23 @@
+//Ex 3.17 page 128
+
+clc;
+clear;
+close;
+
+
+n=3;// no. of phase
+Vs=400;// V
+f=50;// Hz
+alpha = %pi/4;// radian
+Io=10;// A
+Vo=360;// V
+
+// Vo=n*Vs*sqrt(2)/%pi/sqrt(2)-3*2*%pi*f*Ls*Io/%pi
+Ls=(n*Vs*sqrt(2)/%pi/sqrt(2)-Vo)/(3*2*%pi*f)/(Io/%pi)*1000;// mH
+R=Vo/Io;// ohm
+printf(' Load resistance = %.f ohm',R)
+printf('\n Source inductance = %.1f mH',Ls)
+// Vo = n*Vs*sqrt(2)/%pi*cos(alpha+mu)+3*2*%pi*f*Ls*Io/%pi
+mu=acos((Vo-3*2*%pi*f*Ls/1000*Io/%pi)/(n*Vs*sqrt(2)/%pi))-alpha;// radian
+mu=mu*180/%pi;// degree
+printf('\n Overlap angle = %.d degree',mu)
diff --git a/3775/CH3/EX3.2/Ex3_2.sce b/3775/CH3/EX3.2/Ex3_2.sce
new file mode 100644
index 000000000..c276b4c9f
--- /dev/null
+++ b/3775/CH3/EX3.2/Ex3_2.sce
@@ -0,0 +1,17 @@
+//Ex 3.2 page 118
+
+clc;
+clear;
+close;
+
+R=10;// ohm
+E=165;// V
+//vt=330*sin(314*t)
+Vm=330;// V
+f=314/2/%pi;// Hz
+alpha1=asin(E/Vm);// radian
+alpha2=%pi-alpha1;// radian
+Io=1/2/%pi/R*(2*Vm*cos(alpha1)-E*(alpha2-alpha1));// A
+P=E*Io;// W
+
+printf('Power supplied to battery = %d W',P)
diff --git a/3775/CH3/EX3.3/Ex3_3.sce b/3775/CH3/EX3.3/Ex3_3.sce
new file mode 100644
index 000000000..82ba6d895
--- /dev/null
+++ b/3775/CH3/EX3.3/Ex3_3.sce
@@ -0,0 +1,41 @@
+//Ex 3.3 page 119
+
+clc;
+clear;
+close;
+
+//v2t = 325*sin(w*t)
+R=20;// ohm
+alfa=45;// degree
+vm=325;// V
+V=230;// V
+printf('part (a)\n')
+Vo=vm/2/%pi*(1+cosd(alfa)) ;// V
+Io=Vo/R;// A
+printf(' dc voltage Vo = %.1f V',Vo)
+printf('\n & Current Io = %.3f A',Io)
+printf('\n\n part (b)\n')
+Vor=vm/2/sqrt(%pi)*sqrt((%pi-%pi/180*alfa)+1/2*sind(2*alfa));// V
+Ior=Vor/R;// A
+printf(' rms voltage Vor = %.3f V',Vor)
+printf('\n & Current Ior = %.3f A',Ior)
+printf('\n\n part (c)')
+Pdc=Vo*Io;// W
+Pac=Vor*Ior;// W
+eta=Pdc/Pac;// rectification efficiency
+printf("\n dc Power = %.2f W", Pdc)
+printf("\n ac Power = %.2f W", Pac)
+printf("\n Rectification efficiency = %.4f", eta)
+printf('\n\n part (d)')
+FF=Vor/Vo;// form factor
+RF=sqrt(FF**2-1)
+printf('\n Form factor = %.3f ',FF)
+printf('\n Ripple factor = %.3f ',RF)
+printf('\n\n part (e)')
+VA=V*Ior;// VA
+TUF=Pdc/V/Ior;// Transformer Utilization factor
+printf("\n VA rating = %.1f VA", VA)
+printf("\n Transformer Utilization factor = %.4f", TUF)
+printf('\n\n part (f)')
+Vp=vm;// V
+printf("\n Peak inverse voltage = %d V",Vp)
diff --git a/3775/CH3/EX3.4/Ex3_4.sce b/3775/CH3/EX3.4/Ex3_4.sce
new file mode 100644
index 000000000..e057de355
--- /dev/null
+++ b/3775/CH3/EX3.4/Ex3_4.sce
@@ -0,0 +1,23 @@
+//Ex 3.4 page 120
+
+clc;
+clear;
+close;
+
+R=10;// ohm
+E=165;// V
+//vt=330*sin(314*t)
+Vm=330;// V
+Vs=233;// V
+f=314/2/%pi;// Hz
+theta1=asin(E/Vm);// radian
+//alpha2=%pi-alpha1;// radian
+Io=1/2/%pi/R*(2*Vm*cos(theta1)-E*(%pi-2*theta1));// A
+printf('(a) Average value of current = %.2f A',Io)
+P=E*Io;// W
+printf('\n (b) Power supplied to battery = %d W',P)
+Ior=sqrt(1/2/%pi/R**2*((%pi-2*theta1)*(Vs**2+E**2)+Vm**2*sin(2*theta1)-4*Vm*E*cos(theta1)));// A
+Pr=Ior**2*R;// W
+printf('\n (c) Power dissipated in the resistor = %.2f W',Pr)
+pf=(Pr+P)/Vs/Ior;// power factor
+printf('\n (d) Power factor = %.4f',pf)
diff --git a/3775/CH3/EX3.5/Ex3_5.sce b/3775/CH3/EX3.5/Ex3_5.sce
new file mode 100644
index 000000000..754f6a2c0
--- /dev/null
+++ b/3775/CH3/EX3.5/Ex3_5.sce
@@ -0,0 +1,22 @@
+//Ex 3.5 page 122
+
+clc;
+clear;
+close;
+
+R=20;// ohm
+V=230;// V
+f=50;// Hz
+alpha=30;// degree
+Vm=V*sqrt(2);//V
+Vo=Vm/%pi*(1+cos(alpha*%pi/180));// V
+printf('Average load voltage = %.1f V',Vo)
+Io=Vo/R;// A
+printf('\n Average load current = %.2f A', Io)
+Vor=V/sqrt(%pi)*sqrt((%pi-alpha*%pi/180)+sin(2*alpha*%pi/180)/2);// V
+Ior=Vor/R;// A
+printf('\n rms load current = %.2f A', Ior)
+Iav=Io/2;//A
+printf('\n Average thyristor current = %.2f A', Iav)
+Irms=Ior/sqrt(2);// A
+printf('\n rms thyristor current = %.3f A', Irms)
diff --git a/3775/CH3/EX3.6/Ex3_6.sce b/3775/CH3/EX3.6/Ex3_6.sce
new file mode 100644
index 000000000..ed56e8cbd
--- /dev/null
+++ b/3775/CH3/EX3.6/Ex3_6.sce
@@ -0,0 +1,16 @@
+//Ex 3.6 page 122
+
+clc;
+clear;
+close;
+
+R=10;// ohm
+L=100/1000;// H
+E=100;// V
+Vs=230;// V
+f=50;// Hz
+alpha = 45;// degree
+Vm=Vs*sqrt(2);// V
+Vo=2*Vm/%pi*cos(alpha*%pi/180);// V
+Io=(Vo-E)/R;// A
+printf('Average load current = %.3f A',Io)
diff --git a/3775/CH3/EX3.7/Ex3_7.sce b/3775/CH3/EX3.7/Ex3_7.sce
new file mode 100644
index 000000000..09f9bcb2d
--- /dev/null
+++ b/3775/CH3/EX3.7/Ex3_7.sce
@@ -0,0 +1,21 @@
+//Ex 3.7 page 123
+
+clc;
+clear;
+close;
+
+R=2;// ohm
+L=0.3;// H
+E=100;// V
+Vs=230;// V
+f=50;// Hz
+alpha = 30;// degree
+Vm=Vs*sqrt(2);// V
+Vo=2*Vm/%pi*cos(alpha*%pi/180);// V
+printf(' Average load voltage = %.2f V', Vo)
+Io=(Vo)/R;// A
+printf('\n Average load current = %.2f A', Io)
+Is=Io;// A
+Is1=4*Io/%pi/sqrt(2);// A
+PF=Vo*Io/Vs/Is;// power factor
+printf('\n Power factor = %.4f',PF)
diff --git a/3775/CH3/EX3.8/Ex3_8.sce b/3775/CH3/EX3.8/Ex3_8.sce
new file mode 100644
index 000000000..fea42e53b
--- /dev/null
+++ b/3775/CH3/EX3.8/Ex3_8.sce
@@ -0,0 +1,19 @@
+//Ex 3.8 page 123
+
+clc;
+clear;
+close;
+
+R=5;// ohm
+L=1;// H
+E=10;// V
+Vs=230;// V
+f=50;// Hz
+alpha = 45;// degree
+Vm=Vs*sqrt(2);// V
+Vo=Vm/%pi*(1+cos(alpha*%pi/180));// V
+printf(' Average load voltage = %.2f V', Vo)
+Io=(Vo-E)/R;// A
+printf('\n Average load current = %.2f A', Io)
+PF=(Io**2*R+E*Io)/Vs/Io;// power factor
+printf('\n Power factor = %.4f',PF)
diff --git a/3775/CH3/EX3.9/Ex3_9.sce b/3775/CH3/EX3.9/Ex3_9.sce
new file mode 100644
index 000000000..52c125ab1
--- /dev/null
+++ b/3775/CH3/EX3.9/Ex3_9.sce
@@ -0,0 +1,16 @@
+//Ex 3.9 page 124
+
+clc;
+clear;
+close;
+
+R=50;// ohm
+Vs=230;// V
+f=50;// Hz
+alpha = 30;// degree
+Vm=Vs*sqrt(2);// V
+Vo=2*Vm/%pi*cos(alpha*%pi/180);// V
+printf(' (i) Average voltage across 50 ohm resistor = %.2f V', Vo)
+Io=(Vo)/R;// A
+Ior=Io/sqrt(2);// A
+printf('\n (ii) rms current = %.4f A', Ior)
diff --git a/3775/CH4/EX4.1/Ex4_1.sce b/3775/CH4/EX4.1/Ex4_1.sce
new file mode 100644
index 000000000..757ecc342
--- /dev/null
+++ b/3775/CH4/EX4.1/Ex4_1.sce
@@ -0,0 +1,20 @@
+//Ex 4.1 page 158
+
+clc;
+clear;
+close;
+
+
+R=5;// ohm
+Vs=230;// V
+f=50;// Hz
+alpha = 120;// degree
+
+Vor=Vs*sqrt(1/%pi*(%pi-alpha*%pi/180+sin(2*alpha*%pi/180)/2));// V
+printf('\n rms load voltage = %.2f V', Vor)
+Ior=Vor/R;// A
+printf('\n rms load current = %.2f A', Ior)
+Irms=Ior/sqrt(2);//A
+printf('\n rms thyristor current = %.2f A', Irms)
+pf=sqrt(1/%pi*((%pi-alpha*%pi/180)+sin(2*alpha*%pi/180)/2));// power factor
+printf('\n input power factor = %.3f ',pf)
diff --git a/3775/CH4/EX4.2/Ex4_2.sce b/3775/CH4/EX4.2/Ex4_2.sce
new file mode 100644
index 000000000..d25608094
--- /dev/null
+++ b/3775/CH4/EX4.2/Ex4_2.sce
@@ -0,0 +1,28 @@
+//Ex 4.2 page 158
+
+clc;
+clear;
+close;
+
+
+R=10;// ohm
+Vs=230;// V
+f=50;// Hz
+nc=18;// conducting cycles
+noff=32;// off cycles
+
+k=nc/(nc+noff);// duty ratio
+Vor=Vs*sqrt(k);// V
+Po=Vor**2/R;// W
+Pi=Po;// W (losses are negligble)
+Ior=Vor/R;//A
+pf=Po/Vs/Ior;//W
+Im=Vs*sqrt(2)/R;//A
+Irms=Im*sqrt(k)/2;//A
+Iav=k*Im/%pi;//A
+printf('\n (a) rms output voltage = %.0f V', Vor)
+printf('\n (b) Power output to load = %.1f W', Po)
+printf('\n (c) Power input to regulator = %.1f W', Pi)
+printf('\n (d) input power factor = %.1f ',pf)
+printf('\n (e) average scr current = %.3f A', Iav)
+printf('\n     rms scr current = %.3f A', Irms)
diff --git a/3775/CH4/EX4.3/Ex4_3.sce b/3775/CH4/EX4.3/Ex4_3.sce
new file mode 100644
index 000000000..b0ea49598
--- /dev/null
+++ b/3775/CH4/EX4.3/Ex4_3.sce
@@ -0,0 +1,20 @@
+//Ex 4.3 page 159
+
+clc;
+clear;
+close;
+
+
+R=10;// ohm
+Vs=230;// V
+f=50;// Hz
+alpha = 90;// degree
+
+Vor=Vs*sqrt(1/%pi*(%pi-alpha*%pi/180+sin(2*alpha*%pi/180)/2));// V
+Ior=Vor/R;// A
+P=Ior**2*R;// W
+pf=Vor/Vs;// power factor
+printf('\n rms load voltage = %.2f V', Vor)
+printf('\n rms load current = %.2f A', Ior)
+printf('\n power input = %.2f W', P)
+printf('\n load power factor = %.1f ',pf)
diff --git a/3775/CH4/EX4.4/Ex4_4.sce b/3775/CH4/EX4.4/Ex4_4.sce
new file mode 100644
index 000000000..a559736b6
--- /dev/null
+++ b/3775/CH4/EX4.4/Ex4_4.sce
@@ -0,0 +1,16 @@
+//Ex 4.4 page 160
+
+clc;
+clear;
+close;
+
+
+R=30;// ohm
+Vs=230;// V
+f=50;// Hz
+alpha = 45;// degree
+
+Vor=Vs*sqrt(1/%pi*(%pi-alpha*%pi/180+sin(2*alpha*%pi/180)/2));// V
+Ior=Vor/R;// A
+printf('\n rms load voltage = %.2f V', Vor)
+printf('\n rms load current = %.2f A', Ior)
diff --git a/3775/CH4/EX4.5/Ex4_5.sce b/3775/CH4/EX4.5/Ex4_5.sce
new file mode 100644
index 000000000..2ef30291f
--- /dev/null
+++ b/3775/CH4/EX4.5/Ex4_5.sce
@@ -0,0 +1,20 @@
+//Ex 4.5 page 160
+
+clc;
+clear;
+close;
+
+
+R=10;// ohm
+Vs=230;// V
+f=50;// Hz
+fi = 45;// degree
+
+Vmax=Vs;// V(max supply voltage)
+XL=R*tan(fi*%pi/180);// ohm
+Z=XL*sqrt(2);// ohm
+Imax=Vs/Z;//A
+
+printf('\n max load voltage = %.2f V', Vmax)
+printf('\n max load current = %.3f A', Imax)
+printf('\n range of delay angle = %d to %d',0,fi)
diff --git a/3775/CH4/EX4.7/Ex4_7.sce b/3775/CH4/EX4.7/Ex4_7.sce
new file mode 100644
index 000000000..ce881d896
--- /dev/null
+++ b/3775/CH4/EX4.7/Ex4_7.sce
@@ -0,0 +1,24 @@
+//Ex 4.7 page 161
+
+clc;
+clear;
+close;
+
+
+R=3;// ohm
+wL=4;//ohm
+Vs=230;// V
+f=50;// Hz
+
+fi=atan(wL/R)*180/%pi;//degree
+printf('\n (i) control range of firing angle = %.2f to pi',fi)
+Imax=Vs/sqrt(R**2+wL**2);// A
+printf('\n (ii) max rms load current = %.f A', Imax)
+Pmax=Imax**2*R;//W
+printf('\n (iii) max power input to load = %.f W', Pmax)
+pf_max=Pmax/Vs/Imax;// power factor
+printf('\n (iv) max power factor = %.1f ', pf_max)
+Ithrms=Imax/sqrt(2);// A
+Ithav=Ithrms/1.57;// A
+printf('\n (v) max rms thyristor current = %.3f A', Ithrms)
+printf('\n     max average thyristor current = %.3f A', Ithav)
diff --git a/3775/CH5/EX5.1/Ex5_1.sce b/3775/CH5/EX5.1/Ex5_1.sce
new file mode 100644
index 000000000..a7c79e0b4
--- /dev/null
+++ b/3775/CH5/EX5.1/Ex5_1.sce
@@ -0,0 +1,18 @@
+//Ex 5.1 page 184
+
+clc;
+clear;
+close;
+
+R=10;// ohm
+Vs=230;// V
+f=1*1000;// Hz
+Ton=0.4;// ms
+k=0.4 ;// duty cycle
+
+Vo=Vs*k;//V
+Ioav=Vo/R;// A
+Vor=Vs*sqrt(k);// V
+Po=Vor**2/R;// W
+printf('\n Average load current = %.1f A', Ioav)
+printf('\n Power delivered = %.2f W',Po)
diff --git a/3775/CH5/EX5.2/Ex5_2.sce b/3775/CH5/EX5.2/Ex5_2.sce
new file mode 100644
index 000000000..3d3056997
--- /dev/null
+++ b/3775/CH5/EX5.2/Ex5_2.sce
@@ -0,0 +1,20 @@
+//Ex 5.2 page 185
+
+clc;
+clear;
+close;
+
+R=5;// ohm
+Vs=300;// V
+f=1*1000;// Hz
+Ton=20;// ms
+Toff=10;// ms
+
+k= Ton/(Ton+Toff);// duty ratio
+f=1000/(Ton+Toff);//Hz
+Voav=Vs*k;// V
+Ioav=Voav/R;// A
+printf('\n duty ratio = %.3f',k)
+printf('\n chopping frequency = %.2f Hz',f)
+printf('\n Average load voltage = %.2f V', Voav)
+printf('\n Average load current = %.2f A', Ioav)
diff --git a/3775/CH5/EX5.3/Ex5_3.sce b/3775/CH5/EX5.3/Ex5_3.sce
new file mode 100644
index 000000000..149f849c8
--- /dev/null
+++ b/3775/CH5/EX5.3/Ex5_3.sce
@@ -0,0 +1,18 @@
+//Ex 5.3 page 185
+
+clc;
+clear;
+close;
+
+Vs=400;//V
+alfa=0.25;// duty cycle
+delta_I=10;// A
+L=0.5;// H
+R=0;// ohm
+
+Vo=alfa*Vs;//V
+//Vo+L*di/dt=Vs -- putting dt=Ton & di=delta_I
+Ton=delta_I/((Vs-Vo)/L)*1000;// ms
+T=Ton/alfa;// ms
+f=1/T*1000;//Hz
+printf('\n chopping frequency = %d Hz',f)
diff --git a/3775/CH5/EX5.5/Ex5_5.sce b/3775/CH5/EX5.5/Ex5_5.sce
new file mode 100644
index 000000000..77362790a
--- /dev/null
+++ b/3775/CH5/EX5.5/Ex5_5.sce
@@ -0,0 +1,23 @@
+//Ex 5.5 page 186
+
+clc;
+clear;
+close;
+
+Vs=220;//V
+Vo=660;// V
+Toff=100;// micro s
+
+//Vo=Vs/(1-alfa)
+alfa=1-Vs/Vo;// duty cycle
+//alfa=Ton/(Ton+Toff)
+Ton=alfa*Toff/(1-alfa);// micro s
+T=Ton+Toff;//micro s
+printf('Pulse width of output voltage, Ton = %d micro s & T = %d micro s',Ton,T)
+//(ii) reduce pulse width by 50%
+Ton=Ton/2;// micro s
+Toff=T-Ton;// micro s
+alfa=Ton/(Ton+Toff);// duty cycle
+Vo=Vs/(1-alfa);// V
+printf('\n New output voltage = %d V',Vo)
+
diff --git a/3775/CH7/EX7.1/Ex7_1.sce b/3775/CH7/EX7.1/Ex7_1.sce
new file mode 100644
index 000000000..64466ed7d
--- /dev/null
+++ b/3775/CH7/EX7.1/Ex7_1.sce
@@ -0,0 +1,14 @@
+//Ex 7.1 page 260
+
+clc;
+clear;
+close;
+
+N1=1000;// rpm
+Va1=200;// V
+alfa=60;// degree
+Va2=230;// V
+
+N2=2*Va2*sqrt(2)*cos(alfa*%pi/180)*N1/Va1/%pi
+printf('\n Speed of motor = %d rpm',N2)
+// ans in the textbook is not accurate.
diff --git a/3775/CH7/EX7.2/Ex7_2.sce b/3775/CH7/EX7.2/Ex7_2.sce
new file mode 100644
index 000000000..87f099dd3
--- /dev/null
+++ b/3775/CH7/EX7.2/Ex7_2.sce
@@ -0,0 +1,13 @@
+//Ex 7.2 page 260
+
+clc;
+clear;
+close;
+
+N1=1100;// rpm
+Va1=220;// V
+N2=900;// rpm
+
+Va2=Va1*N2/N1;// V
+delta=Va2/Va1;// duty ratio
+printf('\n duty ratio = %.2f',delta)
diff --git a/3775/CH7/EX7.3/Ex7_3.sce b/3775/CH7/EX7.3/Ex7_3.sce
new file mode 100644
index 000000000..d4f0d3334
--- /dev/null
+++ b/3775/CH7/EX7.3/Ex7_3.sce
@@ -0,0 +1,16 @@
+//Ex 7.3 page 261
+
+clc;
+clear;
+close;
+
+N1=900;// rpm
+Va1=198;// V
+N2=500;// rpm
+Vs=230;// V
+
+Va2=Va1*N2/N1;// V
+// 2*sqrt(2)*Vs*cos(alfa)/%pi=Va2
+alfa=acos(Va2/(2*sqrt(2)*Vs)*%pi)*180/%pi;// degree
+
+printf('\n triggering angle = %.1f degree',alfa)
diff --git a/3775/CH7/EX7.4/Ex7_4.sce b/3775/CH7/EX7.4/Ex7_4.sce
new file mode 100644
index 000000000..f0605a583
--- /dev/null
+++ b/3775/CH7/EX7.4/Ex7_4.sce
@@ -0,0 +1,20 @@
+//Ex 7.4 page 261
+
+clc;
+clear;
+close;
+
+Vs=230;// V
+Ton=10;// ms
+Toff=25;// ms
+Ra=2;//ohm
+N=1400;// rpm
+k=0.5;// V/rad/s (back emf constant)
+kt=0.5;// NM-A**-1 (torque constant)
+
+Eb=N*2*%pi*k/60;// V
+Va=Vs*Ton/(Toff);// V
+Ia=(Va-Eb)/Ra;// A
+T=kt*Ia;// Nm
+printf('\n average armature current = %.2f A', Ia)
+printf('\n torque = %.3f Nm', T)