initial commit / add all books

20 files changed, 505 insertions, 0 deletions

diff --git a/2375/CH3/EX3.1/ex3_1.sce b/2375/CH3/EX3.1/ex3_1.sce
new file mode 100755
index 000000000..8783b711f
--- /dev/null
+++ b/2375/CH3/EX3.1/ex3_1.sce
@@ -0,0 +1,20 @@
+// Exa 3.1

+clc;

+clear;

+close;

+format('v',6)

+// Given data

+V_CC = 15;// in V

+R_C = 4;// in k ohm

+R_C =R_C * 10^3;// in ohm

+I_C = 0;// in A

+V_CE = V_CC - (I_C*R_C);// in V

+V_CE = 0;// in V

+// V_CE = V_CC - I_C*R_C;

+I_C = V_CC/R_C;// in A

+I_C = I_C * 10^3;// in mA

+plot([V_CC 0],[0 I_C])

+xlabel("V_CE in volts")

+ylabel("I_C in mA")

+title("DC load line")

+disp("DC load line shown in figure")

diff --git a/2375/CH3/EX3.10/ex3_10.sce b/2375/CH3/EX3.10/ex3_10.sce
new file mode 100755
index 000000000..ce88dda68
--- /dev/null
+++ b/2375/CH3/EX3.10/ex3_10.sce
@@ -0,0 +1,21 @@
+// Exa 3.10

+clc;

+clear;

+close;

+format('v',5);

+// Given data

+V_CC = 10;// in V

+R_C = 1;// in k ohm

+R_B = 100;//in k ohm

+V_CE = 5;// in V

+V_BE = 0.7;// in V

+V_CB= V_CE-V_BE;// in V

+I_B= V_CB/R_B;// in mA

+// V_CC = (I_C+I_B)*R_C + V_CE = I_C*R_C + I_B*R_C + V_CE;

+I_C =  (V_CC-V_CE-(I_B*R_C))/R_C;// in mA

+bita= I_C/I_B;

+S = (1 + bita)/( 1 + bita*( R_C/(R_B+R_C) ) );

+disp(S,"The value of stability factor is");

+S_fixed_bias= 1+bita;// stability factor for fixed bias circuit

+disp(S_fixed_bias,"For the fixed bias circuit, the value of stability factor would have been")

+disp("Thus collector to base circuit has a low value of S and hence provides better Q point stability")

diff --git a/2375/CH3/EX3.11/ex3_11.sce b/2375/CH3/EX3.11/ex3_11.sce
new file mode 100755
index 000000000..0fdfe7eee
--- /dev/null
+++ b/2375/CH3/EX3.11/ex3_11.sce
@@ -0,0 +1,22 @@
+// Exa 3.11

+clc;

+clear;

+close;

+format('v',5)

+//Given data

+Beta = 100;

+V_CC = 10;// V

+R1 = 9.1;// in k ohm

+R_C = 1;// in k ohm

+R_E = 560*10^-3;// in  k ohm

+R2 = 4.7;// in k ohm

+V_BE = 0.7;// in V

+V_Th = (V_CC/(R1+R2))*R2;// in V

+R_B = (R1*R2)/(R1+R2);// in k ohm

+// V_Th - I_B*R_B - V_BE - I_E*R_E = 0 or 

+I_B = (V_Th-V_BE)/(R_B+((1+Beta)*R_E));// in mA

+// I_C = Beta*I_B + (1+Beta)*I_CO;

+I_C = Beta*I_B;// in mA (neglecting I_CO as it is very small)

+// V_CC - (I_C*R_C) - V_CE - I_E*R_E = 0;

+V_CE = V_CC - (I_C*R_C) - (I_C*R_E);// in V

+disp("Q Point : "+string(V_CE)+" volts, "+string(I_C)+" mA")

diff --git a/2375/CH3/EX3.12/ex3_12.sce b/2375/CH3/EX3.12/ex3_12.sce
new file mode 100755
index 000000000..136ccab75
--- /dev/null
+++ b/2375/CH3/EX3.12/ex3_12.sce
@@ -0,0 +1,22 @@
+// Exa 3.12

+clc;

+clear;

+close;

+format('v',6)

+// Given data

+V_CC = 20;// in V

+bita = 50;

+R_C = 2;// in k ohm

+R_E = 0.1;// in k ohm

+R1 = 100;// in k ohm

+R2 = 5;// in k ohm

+R_Th = (R1*R2)/(R1+R2);// in k ohm

+R_B = R_Th;// in k ohm

+V_BE = 0.7;// in V

+V_Th = (V_CC*R2)/(R1+R2);// in V

+// Applying KVL to the base circuit, V_Th  - I_B*R_B - V_BE - I_E*R_E = 0 or

+I_B = (V_Th-V_BE)/(R_B + (R_E*(1+bita)));// in mA     (on putting I_E= (1+bita)*I_B)

+I_C = bita*I_B;// in mA

+I_E = (1+bita)*I_B;// in mA

+V_CE = V_CC - (I_C*R_C) - (I_E*R_E);// in V

+disp("Q Point : "+string(V_CE)+" volts, "+string(I_C)+" mA")

diff --git a/2375/CH3/EX3.13/ex3_13.sce b/2375/CH3/EX3.13/ex3_13.sce
new file mode 100755
index 000000000..69e515f3a
--- /dev/null
+++ b/2375/CH3/EX3.13/ex3_13.sce
@@ -0,0 +1,43 @@
+// Exa 3.13

+clc;

+clear;

+close;

+format('v',5)

+// Given data

+bita= 44;

+V_BE = 0.2;// in V

+V_CC = -4.5;// in V

+R1 = 2.7;// in k ohm

+R_C = 1.5;// in k ohm

+R2 = 27;// in k ohm

+R_E = 0.27;// in k ohm

+R_Th = (R1*R2)/(R1+R2);// in k ohm

+R_B = R_Th;// in k ohm

+V_Th = (V_CC*R_B)/R2;// in V

+I_B= poly(0,'I_B');// in mA

+I_C= bita*I_B;// in mA

+I_E= -(I_C+I_B);// in mA

+// Applying KVL to base circuit, -V_Th - I_B*R_B - V_BE + (I_E*R_E) = 0     (i)

+I_B= (V_Th - I_B*R_B + V_BE + (I_E*R_E));// in mA

+I_B= roots(I_B);// in mA

+I_C= bita*I_B;// in mA

+I_E= -(I_C+I_B);// in mA

+// Applying KVL to collector circuit, -V_CC - I_C*R_C - V_CE + I_E*R_E = 0 or 

+V_CE = V_CC - (I_C*R_C) + (I_E*R_E);// in V

+disp("Part (a) : ")

+disp("Q Point : "+string(V_CE)+" volts, "+string(I_C)+" mA")

+// Calculation of R'Th or R'B (Thevenin's Resistance)

+r_bb = 0.69;// in k ohm

+R_deshB = ((R1*R2)/(R1+R2)) + r_bb;// in k ohm

+// Calculation of Thevenin's voltage

+I_B= (V_Th+V_BE)/(R_deshB+(1+bita)*R_E);// in mA

+I_C= bita*I_B;// in mA

+// Applying KVL to collector circuit, -V_CC - (I_C*R_C) - V_CE + I_E*R_E = 0 or

+V_CE = V_CC - (I_C*R_C) + (I_E*R_E);// in V

+disp("Part (b) : ")

+disp("Q Point : "+string(V_CE)+" volts, "+string(I_C)+" mA")

+

+

+

+

+

diff --git a/2375/CH3/EX3.14/ex3_14.sce b/2375/CH3/EX3.14/ex3_14.sce
new file mode 100755
index 000000000..97b940662
--- /dev/null
+++ b/2375/CH3/EX3.14/ex3_14.sce
@@ -0,0 +1,30 @@
+// Exa 3.14

+clc;

+clear;

+close;

+format('v',5)

+// Given data

+bita = 140;

+V_BE = 0.7;// in V

+V_CC = 22;// in V

+R1 = 39;// in k ohm

+R_C = 10;// in k ohm

+R2 = 3.9;// in k ohm

+R_E = 1.5;// in k ohm

+// Calculation of Thevenin's Resistance

+R_Th = (R1*R2)/(R1+R2);// in k ohm

+// Calculation of Thevenin's Voltage

+V_Th = (V_CC*R2)/(R1+R2);// in V

+I_B= poly(0,'I_B');// in mA

+I_E= (1+bita)*I_B;// in mA

+// Applying KVL to input side, V_Th - I_B*R_Th - V_BE - I_E*R_E=0 or 

+I_B= V_Th - I_B*R_Th - V_BE - I_E*R_E;

+I_B= roots(I_B);// in mA

+I_C = bita*I_B;// in mA

+I_E= (1+bita)*I_B;// in mA

+// Applying KVL to C-E circuit, V_CC - I_C*R_C - V_CE - I_E*R_E = 0 or

+V_CE = V_CC - (I_C*R_C) - ((1+bita)*I_B*R_E);// in V

+I_B= I_B*10^3;// in µA

+disp(I_B,"The value of I_B in µA is");

+disp(I_C,"The value of I_C in mA is");

+disp(V_CE,"The value of V_CE in V is");

diff --git a/2375/CH3/EX3.15/ex3_15.sce b/2375/CH3/EX3.15/ex3_15.sce
new file mode 100755
index 000000000..67f75374d
--- /dev/null
+++ b/2375/CH3/EX3.15/ex3_15.sce
@@ -0,0 +1,26 @@
+// Exa 3.15

+clc;

+clear;

+close;

+format('v',5)

+// Given data

+V_CC =12;// in V

+R_C = 4.3;// in k ohm

+V_CE = 4;// in V

+V_BE = 0.7;// in V

+V_EE = 6;// in V

+bita = 50;

+// Applying KVL in base circuit, -V_BE - I_ER_E + V_EE = 0 or

+I_ER_E = V_EE - V_BE;// in V

+// Applying KVL in C-E circuit, V_CC-I_C*R_C-V_CE-I_ER_E+V_EE=0 or

+I_C = (V_CC - V_CE - I_ER_E + V_EE)/R_C;// in mA

+I_B = I_C/bita;// in mA

+I_E = I_C+I_B;// in mA

+R_E= I_ER_E/I_E;// in k ohm

+disp(R_E,"The value of R_E in k ohm is : ")

+del_IC= bita*(1+bita)*R_E;

+del_ICO= bita*(1+bita)*R_E;

+S= del_IC/del_ICO;

+disp(S,"The value of stability factor, S is : ")

+S_desh= bita/((1+bita)*R_E);

+disp(S_desh,"The value of stability factor, S'' is : ")

diff --git a/2375/CH3/EX3.17/ex3_17.sce b/2375/CH3/EX3.17/ex3_17.sce
new file mode 100755
index 000000000..bcf7831f4
--- /dev/null
+++ b/2375/CH3/EX3.17/ex3_17.sce
@@ -0,0 +1,17 @@
+// Exa 3.17           (Miss printed as example 3.14)

+clc;

+clear;

+close;

+format('v',5)

+// Given data

+Tj = 150;//Junction temperature in degree C

+P_Cmax = 125;// in mW

+T = 25;// free-air temperature in degree C

+T1 = 0;// in degree C

+curve = (Tj-T)/(P_Cmax - T1);// in degreeC/mW

+T_A = 25;// Ambient temperature in degree C

+P_D = 75;// Collector junction dissipation in mW

+theta = 1;// in degree C/mW

+// Tj-T_A = theta*P_D;

+Tj = T_A + (theta*P_D);// in degree C

+disp(Tj,"The junction temperature in °C is");

diff --git a/2375/CH3/EX3.18/ex3_18.sce b/2375/CH3/EX3.18/ex3_18.sce
new file mode 100755
index 000000000..2bd6c1fab
--- /dev/null
+++ b/2375/CH3/EX3.18/ex3_18.sce
@@ -0,0 +1,18 @@
+// Exa 3.18             (Miss printed as example 3.15)

+clc;

+clear;

+close;

+format('v',5)

+// Given data

+P_Cmax = 125;// in mW

+P_D = P_Cmax;// in mW

+T_A = 25;// in degree C

+Tj = 150;// in degree C

+// Tj-T_A = theta*P_D;

+theta = (Tj-T_A)/P_D;// in degree C/mW

+disp(theta,"The thermal resistance for a transistor in °C/mW is");

+// For theta= 1 °C/mW

+P_D = 75;// in mW

+// Tj-T_A = theta*P_D;

+Tj = (theta*P_D) + T_A;// in degree C

+disp(Tj,"The junction temperature in °C is");

diff --git a/2375/CH3/EX3.2/ex3_2.sce b/2375/CH3/EX3.2/ex3_2.sce
new file mode 100755
index 000000000..e425e40f1
--- /dev/null
+++ b/2375/CH3/EX3.2/ex3_2.sce
@@ -0,0 +1,17 @@
+// Exa 3.2

+clc;

+clear;

+close;

+format('v',6)

+// Given data

+R_C = 5;// in k ohm

+V_CC = 10;// in V

+I_C = 1;// in mA

+V_CE = V_CC - (I_C*R_C);// in V

+disp("Part (i) When Collector load = 5 kohm");

+disp("Operating point is : "+string(V_CE)+" V, "+string(I_C)+" mA")

+disp("The quiescent point 5V and 1mA");

+R_C = 6;// in k ohm

+V_CE = V_CC - (I_C*R_C);// in V

+disp("Part (ii) When Collector load = 6 kohm");

+disp("Operating point is : "+string(V_CE)+" V, "+string(I_C)+" mA")

diff --git a/2375/CH3/EX3.20/ex3_20.sce b/2375/CH3/EX3.20/ex3_20.sce
new file mode 100755
index 000000000..2a7d1147e
--- /dev/null
+++ b/2375/CH3/EX3.20/ex3_20.sce
@@ -0,0 +1,36 @@
+// Exa 3.20                 (Miss printed as example 3.17)

+clc;

+clear;

+close;

+format('v',7)

+// Given data

+V_E = 1;// in V

+V_BE = 0.7;// in V

+R_C = 1;// in k ohm

+Beta = 180;

+V_CC = 12;// in V

+V_CEQ = 6;// in V

+// Applying KVL into collector circuit, V _CC - I_C*R_C - V_CEQ = 0 or

+I_C = (V_CC-V_CEQ)/R_C;// in mA

+I_B = I_C/Beta;// in mA

+// Applying KVL into base circuit, V_CC - I_B*R_B - V_BE = 0 or

+R_B = (V_CC-V_BE)/I_B;// in k ohm

+disp(R_B,"The value of R_B in k ohm is");

+//Applying KVL to collector circuit, V_CC - I_C*R_C - V_CE - V_E = 0 or

+I_C = (V_CC-V_CEQ-V_E)/R_C;// in mA

+I_B = I_C/Beta;// in mA

+I_E = I_C+I_B;// in mA

+R_E = V_E/(I_E);// in k ohm

+R_E= round(R_E*10^3);// in ohm

+disp(R_E,"The value of R_E in ohm is");

+I_R2 = 10*I_B;// in mA

+V_BE= 0.6;// in V

+//R2 =V_B/I_R2 = (V_E+V_BE)/I_R2;

+R2 = (V_E+V_BE)/I_R2;// in k ohm 

+R2= R2*10^3;// in ohm

+disp(R2,"The value of R2 in ohm is");

+I_R1 = I_R2 + I_B;// in mA

+//R1 = V_R1/I_R1 = (V_CC-V_B)/I_R1;

+V_B = V_E+V_BE;// in V

+R1 = (V_CC-V_B)/I_R1;// in k ohm

+disp(R1,"The value of R1 in k ohm is");

diff --git a/2375/CH3/EX3.21/ex3_21.sce b/2375/CH3/EX3.21/ex3_21.sce
new file mode 100755
index 000000000..48b304d75
--- /dev/null
+++ b/2375/CH3/EX3.21/ex3_21.sce
@@ -0,0 +1,37 @@
+// Exa 3.21                 (Miss printed as example 3.18)

+clc;

+clear;

+close;

+format('v',5)

+// Given data

+V_BB= 6;// in V

+I_CBO =0.5;// in µA

+V_BE = 0.7;// in V

+R_B= 50;// in k ohm

+R_E= 1;// in k ohm

+bita = 75;

+// V_BB - I_B*R_B - V_BE - I_E*R_E = 0 or

+I_B=(V_BB-V_BE)/(R_B+(1+bita)*R_E);// in mA      (on putting I_E= (1+bita)*I_B)             (i)

+I_B= round(I_B*10^3);// in µA

+I_C= bita*I_B;// in µA

+I_C= I_C*10^-3;// in mA

+I_CQ= I_C;// in mA

+disp(I_CQ,"The value of I_CQ at room temperature in mA is : ")

+// Part (ii)

+C= 2;// temperature coefficient in mV/°C

+C= 2*10^-3;// in V/°C

+T2= 20;// in °C

+T1= 0;// in °C

+I_CBO2= I_CBO*2^((T2-T1)/10);// in µA

+V_BE2= V_BE-C*T2;// in V

+// Now from eq(i), for the new value of I_B

+I_B=(V_BB-V_BE2)/(R_B+(1+bita)*R_E);// in mA

+I_B= I_B*10^3;// in µA

+I_C= bita*I_B+(1+bita)*I_CBO2;// in µA

+I_C= I_C*10^-3;// in mA

+I_CQ= I_C;// in mA

+disp(I_CQ,"The value of I_CQ when temperature increases by 20°C in mA is : ")

+

+

+

+

diff --git a/2375/CH3/EX3.22/ex3_22.sce b/2375/CH3/EX3.22/ex3_22.sce
new file mode 100755
index 000000000..d8f9633f2
--- /dev/null
+++ b/2375/CH3/EX3.22/ex3_22.sce
@@ -0,0 +1,40 @@
+// Exa 3.22                 (Miss printed as example 3.19)

+clc;

+clear;

+close;

+format('v',6)

+// Given data

+S = 10;

+bita = 50;

+h_fe = bita;

+V_CC= 20;// in V

+V_CE = 10;// in V

+R_C = 2;// in k ohm

+I_C = 4;// in mA

+I_B =I_C/bita;// in mA

+// Applying KVL to collector loop, V_CC -I_C*R_C - V_CE - I_E*R_E = 0 or

+R_E = (V_CC -I_C*R_C - V_CE)/(I_C+I_B);// in k ohm            (on putting I_E= I_C+I_B)

+R_E= round(R_E*10^3);// in ohm

+disp(R_E,"The value of R_E in ohm is");

+// Formula S = (1+bita)*( (1 + (R_B/R_E))/( (1+bita) + (R_B/R_E) ) ) or

+R_B= (1+bita)*(1-S)*R_E/(S-1-bita);// in ohm

+// But R_B= R1 || R2= R1*R2/(R1+R2) => R2/(R1+R2)= R_B/R1           (i)

+// Calculation of R1 and R2 : 

+V_BE= 0.2;// in V

+// Applying KVL to input loop, 

+V_R2= V_BE+(I_C+I_B)*10^-3*R_E;// in V

+// But V_R2= R2*V_CC/(R1+R2) =>  R2/(R1+R2)= V_R2/V_CC          (ii)

+// On comparing eq (i) and (ii)

+R1= R_B*V_CC/V_R2;// in ohm

+R2= R1*V_R2/(V_CC-V_R2);// in ohm

+R1= R1*10^-3;// in k ohm

+R2= R2*10^-3;// in k ohm

+disp(R1,"The value of R1 in k ohm is : ")

+disp(R2,"The value of R2 in k ohm is : ")

+// Effect of Reducing S or 3 : 

+S=3;

+// Formula S = (1+bita)*( (1 + (R_B/R_E))/( (1+bita) + (R_B/R_E) ) ) or

+R_B= (1+bita)*(1-S)*R_E/(S-1-bita);// in ohm

+R_B= R_B*10^-3;// in k ohm

+disp(R_B,"When S<=3, the value of R_B in k ohm is : ")

+disp("Thus S is reduced below 3 at the cost of reduction of it''s input impedance")

diff --git a/2375/CH3/EX3.3/ex3_3.sce b/2375/CH3/EX3.3/ex3_3.sce
new file mode 100755
index 000000000..6d143206c
--- /dev/null
+++ b/2375/CH3/EX3.3/ex3_3.sce
@@ -0,0 +1,18 @@
+// Exa 3.3

+clc;

+clear;

+close;

+format('v',6)

+// Given data

+Beta = 100;

+V_CC = 10;// in V

+V_BE = 0.7;// in V

+R_B = 150;// in k ohm

+// V_CC - I_B*R_B - V_BE = 0;

+I_B = (V_CC-V_BE)/R_B;// in mA

+// I_C = Beta*I_B + (1+Beta)*I_CO;

+I_C = Beta * I_B;// in A

+// V_CC - I_C*R_C - V_CE = 0;

+R_C = 1;// in k ohm

+V_CE = V_CC - (I_C*R_C);// in V

+disp("The operating point is : "+string(V_CE)+" V, "+string(I_C)+" mA")

diff --git a/2375/CH3/EX3.4/ex3_4.sce b/2375/CH3/EX3.4/ex3_4.sce
new file mode 100755
index 000000000..15dcfedfc
--- /dev/null
+++ b/2375/CH3/EX3.4/ex3_4.sce
@@ -0,0 +1,32 @@
+// Exa 3.4

+clc;

+clear;

+close;

+format('v',6)

+// Given data

+V_CC = 12;// in V

+R_C = 2.2;// in k ohm

+R_C = R_C * 10^3;// in ohm

+R_B = 240;//in k ohm

+R_B = R_B * 10^3;// in ohm

+V_BE = 0.7;// in V

+// V_CC - I_B*R_B - V_BE = 0;

+I_BQ = (V_CC-V_BE)/R_B;// in A

+I_BQ = I_BQ * 10^6;// in µA

+disp(I_BQ,"The value of I_BQ in µA is");

+Beta = 50;

+// I_CQ = Beta*I_BQ + (1+BEta)*I_CO;

+I_CQ = Beta*I_BQ*10^-6;// in A

+I_CQ = I_CQ * 10^3;// in mA

+disp(I_CQ,"The value of I_CQ in mA is");

+// V_CC - I_CQ*R_C - V_CEQ = 0;

+V_CEQ = V_CC - I_CQ*10^-3*R_C;// in V

+disp(V_CEQ,"The value of V_CEQ in V is");

+V_B = V_BE;// in V

+disp(V_B,"The value of V_B in V is");

+V_C = V_CEQ;// in V

+disp(V_C,"The value of V_C in V is");

+// V_CE = V_CB + V_BE;

+V_CB = V_CEQ - V_BE;// in V

+V_BC = -V_CB;// in V

+disp(V_BC,"The value of V_BC in V is");

diff --git a/2375/CH3/EX3.5/ex3_5.sce b/2375/CH3/EX3.5/ex3_5.sce
new file mode 100755
index 000000000..614c4f5c0
--- /dev/null
+++ b/2375/CH3/EX3.5/ex3_5.sce
@@ -0,0 +1,25 @@
+// Exa 3.5

+clc;

+clear;

+close;

+format('v',6)

+// Given data

+V_CC = 12;// in V

+R_B = 100;// in k ohm

+R_C = 500*10^-3;// in k ohm

+Beta_dc = 100;

+V_BE= 0.7;// in V

+// V_CC - I_BQ*R_B - V_BE = 0;

+I_BQ = (V_CC - V_BE)/R_B;// in mA

+I_CQ = Beta_dc*I_BQ;// in mA

+// V_CC - I_CQ*R_C - V_CEQ = 0;

+V_CEQ = V_CC - (I_CQ*R_C);// in V

+disp("The Q point at 30° is : "+string(V_CEQ)+" V, "+string(I_CQ)+" mA")

+Beta_dc = 120;

+I_CQ1 = Beta_dc*I_BQ;// in mA

+V_CEQ1 = V_CC - (I_CQ1*R_C);// in V

+disp("The Q point at 80° is : "+string(V_CEQ1)+" V, "+string(I_CQ1)+" mA")

+PerI_CQ = ((I_CQ1-I_CQ)/I_CQ)*100;// in %

+disp("The percentage change in I_CQ is : "+string(PerI_CQ )+" % (increase)");

+PerV_CEQ = ((V_CEQ1-V_CEQ)/V_CEQ)*100;// in %

+disp("The percentage change in V_CEQ is : "+string(abs(PerV_CEQ))+" % (decrease)");

diff --git a/2375/CH3/EX3.6/ex3_6.sce b/2375/CH3/EX3.6/ex3_6.sce
new file mode 100755
index 000000000..fb4d530d9
--- /dev/null
+++ b/2375/CH3/EX3.6/ex3_6.sce
@@ -0,0 +1,22 @@
+// Exa 3.36

+clc;

+clear;

+close;

+format('v',5)

+// Given data

+R_B = 100;// in k ohm

+R_B = R_B * 10^3;// in ohm

+R_C = 1;// in k ohm

+R_C = R_C * 10^3;// in ohm

+V_BE = 0.3;// in V

+// S = 1 + Beta and Beta = I_C/I_B;

+V_CC = 12;// in V

+V_CE = 6;// in V

+I_C = (V_CC-V_CE)/R_C;// in A

+I_C = I_C * 10^3;// in mA

+I_B = (V_CC-V_BE)/R_B;// in A

+I_B = I_B * 10^6;// in µA

+Beta = (I_C*10^-3)/(I_B*10^-6);

+S = 1 + Beta;

+disp(S,"The stability factor is");

+

diff --git a/2375/CH3/EX3.7/ex3_7.sce b/2375/CH3/EX3.7/ex3_7.sce
new file mode 100755
index 000000000..2e7cb3584
--- /dev/null
+++ b/2375/CH3/EX3.7/ex3_7.sce
@@ -0,0 +1,21 @@
+// Exa 3.7

+clc;

+clear;

+close;

+format('v',6)

+// Given data

+V_CC = 25;// in V

+R_B = 180;// in k ohm

+R_C = 820*10^-3;// in k ohm

+R_E = 200*10^-3;// in k ohm

+bita = 80;

+V_BE = 0.7;// in V

+// Applying KVL to B-E loop, V_CC-I_B*R_B-V_BE-I_E*R_E=0 or 

+I_C= (V_CC-V_BE)/((R_B+R_E)/bita-R_E);// in A   (on putting I_B= I_C/bita and I_E= I_B+I_E)

+disp(I_C,"The collector current in mA is");

+V_CE = V_CC - (I_C*R_C);// in V

+disp(V_CE,"The collector to emmiter voltage in V is");

+S = (1 + bita)/( 1 + ( (bita*R_E)/(R_B+R_E) ) );

+disp(S,"Current stability factor is");

+Sdas = -bita/( R_B + R_E*(1+bita) );

+disp(Sdas,"The voltage stability factor is");

diff --git a/2375/CH3/EX3.8/ex3_8.sce b/2375/CH3/EX3.8/ex3_8.sce
new file mode 100755
index 000000000..327acc34a
--- /dev/null
+++ b/2375/CH3/EX3.8/ex3_8.sce
@@ -0,0 +1,19 @@
+// Exsa 3.8

+clc;

+clear;

+close;

+format('v',6)

+// Given data

+V_CC = 20;// in V

+V_BE= 0.7;// in V

+R_C = 4.7;//in k ohm

+bita = 100;

+R_B = 680;// in k ohm

+I_C= poly(0,'I_C');// in mA

+I_B= I_C/bita;// in  mA

+// Applying KVL to C-B circuit, V_CC - (I_C+I_B)*R_C - I_B*R_B - V_BE = 0;

+I_C= V_CC - (I_C+I_B)*R_C - I_B*R_B - V_BE;

+I_C= roots(I_C);// in mA

+I_B= I_C/bita;// in  mA

+V_CEQ = V_CC - (I_C+I_B)*R_C;// in V

+disp("Q point : "+string(V_CEQ)+" volts, "+string(I_C)+" mA")

diff --git a/2375/CH3/EX3.9/ex3_9.sce b/2375/CH3/EX3.9/ex3_9.sce
new file mode 100755
index 000000000..c248ffbed
--- /dev/null
+++ b/2375/CH3/EX3.9/ex3_9.sce
@@ -0,0 +1,19 @@
+// Exa 3.9

+clc;

+clear;

+close;

+format('v',6)

+// Given data

+V_CEQ = 5;// in V

+I_CQ = 5;// in mA

+V_CC = 12;// in V

+bita = 120;

+I_C = I_CQ;// in mA

+V_BE = 0.7;// in V

+I_B= I_C/bita;// in mA

+// V_CC - (I_C+I_B)*R_C - V_CE = 0 or

+R_C= (V_CC-V_CEQ)/(I_C+I_B);// in k ohm

+// Applying KVL to base circuit, V_CC - (I_C+I_B)*R_C - I_B*R_B - V_BE = 0 or 

+R_B= (V_CEQ-V_BE)/I_B;// in k ohm

+disp(R_C,"The value of R_C in k ohm is");

+disp(R_B,"The value of R_B in k ohm is");