Chapter 13 : TRANSISTOR AND OTHER DEVICES

Example 13.1 Page No : 388

In [1]:
#INPUT DATA
Ie = 10;			#emitter current in mA
Ic = 9.8;			#collector current in mA
#CALCULATIONS
Ib = Ie-Ic;			#base current in mA
print "base current is %1.1f mA "%(Ib)

base current is 0.2 mA

Example 13.2 Page No : 389

In [2]:
#INPUT DATA
Ie = 6.28;			#emitter current in mA
Ic = 6.20;			#collector current in mA
#CALCULATIONS
a = (Ic/Ie);			#current gain
print "current gain  is %1.3f"%(a)

current gain  is 0.987

Example 13.3 Page No : 389

In [3]:
#INPUT DATA
a = 0.967			#common-base DC current gain
Ie = 10;			#emitter current in mA
#CALCULATIONS
Ic = Ie*a;			#collector current in mA
Ib = Ie-Ic;			#base current in mA
print "base current is %1.2f mA"%(Ib)

base current is 0.33 mA

Example 13.4 Page No : 389

In [4]:
#INPUT DATA
a = 0.98			#common-base DC current gain
Ie = 10;			#emitter current in mA
#CALCULATIONS
Ic = Ie*a;			#collector current in mA
Ib = Ie-Ic;			#base current in mA
print "base current is %1.1f mA"%(Ib)

base current is 0.2 mA

Example 13.5 Page No : 389

In [6]:
#INPUT DATA
a = 0.97			#common-base DC current gain
b = 200.;			#common-emitter DC current gain
#CALCULATIONS
b1 = a/(1-a);			#common-emitter DC current gain when a = 0.97
a1 = b/(b+1);			#common-base DC current gain when b = 200
print "Thus common-emitter DC current gain when a = 0.97 and common-base DC current gain when \
\nb = 200 are %2.2f and %1.3f respectively "%(b1,a1)

Thus common-emitter DC current gain when a = 0.97 and common-base DC current gain when 
b = 200 are 32.33 and 0.995 respectively

Example 13.6 Page No : 389

In [7]:
#INPUT DATA
Ic = 40;			#collector current in mA
b = 100.;			#common-emitter DC current gain
#CALCULATIONS
Ib = Ic/b;			#base current in mA
Ie = Ib+Ic;			#emitter current in mA
print "Thus emitter current is %2.1f mA"%(Ie);

Thus emitter current is 40.4 mA

Example 13.7 Page No : 390

In [8]:
#INPUT DATA
Ie = 10;			#emitter current in mA
b = 150.;			#common-emitter DC current gain
#CALCULATIONS
a = b/(b+1);			#common-base DC current gain
Ic = a*Ie;			#collector current in mA
Ib = Ie-Ic;			#base current in mA
print "Thus collector and base currents are %1.2f mA and %1.2f mA respectively"%(Ic,Ib);

Thus collector and base currents are 9.93 mA and 0.07 mA respectively

Example 13.8 Page No : 390

In [9]:
#INPUT DATA
Ic = 80;			#collector current in mA
b = 170.;			#common-emitter DC current gain
#CALCULATIONS
Ib = Ic/b;			#base current in mA
Ie = Ib+Ic;			#emitter current in mA
print "Thus emitter and base currents are %2.2f mA and %1.2f mA respectively"%(Ie,Ib);

Thus emitter and base currents are 80.47 mA and 0.47 mA respectively

Example 13.9 Page No : 390

In [10]:
#INPUT DATA
Ib = 0.125;			#base current in mA
b = 200;			#common-emitter DC current gain
#CALCULATIONS
Ic = b*Ib;			#collector current in mA
Ie = Ib+Ic;			#emitter current in mA
print "Thus emitter and collector currents are %2.3f mA and %d mA respectively"%(Ie,Ic);

Thus emitter and collector currents are 25.125 mA and 25 mA respectively

Example 13.10 Page No : 391

In [11]:
#INPUT DATA
Ie = 12.;			#emitter current in mA
b = 100.;			#common-emitter DC current gain
#CALCULATIONS
Ib = Ie/(1+b);			#base current in mA
Ic = Ie-Ib;			#collector current in mA
print "Thus base and collector currents are %1.4f mA and %2.4f mA respectively"%(Ib,Ic);

Thus base and collector currents are 0.1188 mA and 11.8812 mA respectively

Example 13.11 Page No : 391

In [12]:
#INPUT DATA
Ib = 100*10**-6;			#base current in A
Ic = 2*10**-3;			#collector current in A
Ib1 = 125*10**-6;			#base current in A when change in Ib is 25 A
Ic1 = 2.6*10**-3;			#collector current in A when change in Ic is 0.6 A
#CALCULATIONS
b = Ic/Ib;			#common-emitter DC current gain
a = (b)/(b+1);			#common-base DC current gain
Ie = Ib+Ic;			#emitter current in A
b1 = Ic1/Ib1;			#new common-emitter DC current gain
print "Thus b  a and Ie of transistor are %d ,%1.3f and %g A respectively"%(b,a,Ie);
print "new value of b is %2.1f"%(b1)

Thus b  a and Ie of transistor are 20 ,0.952 and 0.0021 A respectively
new value of b is 20.8

Example 13.12 Page No : 391

In [13]:
#INPUT DATA
a = 0.98			#common-base DC current gain
Icbo = 5*10**-6;			#current in A
Ib = 100*10**-6;			#base current in A
#CALCULATIONS
Ic = ((a*Ib)/(1-a))+(Icbo/(1-a));			#collector current in mA
Ie = Ib+Ic;			#emitter current in mA
print "Thus collector and emitter currents are %g A and %g A respectively"%(Ic,Ie);

Thus collector and emitter currents are 0.00515 A and 0.00525 A respectively

Example 13.13 Page No : 391

In [15]:
#INPUT DATA
Icbo = 10*10**-6;			#current in A
hfe = 50;			#common-emitter DC current gain
Ib = 0.25*10**-3;			#base current in A
T2 = 50;			#temperature in degree centigrade
T1 = 27;			#temperature in degree centigrade
#CALCULATIONS
Ic1 = (hfe*Ib)+((1+hfe)*(Icbo));			#collector current in A when base current is Ib = 0.25*10**-3
I1cbo = Icbo*(2*(T2-T1)/10);			#new value of Icbo when temperature changes from 27 degree centigrade to 50 degree centigrade
Ic2 = (hfe*Ib)+((1+hfe)*(I1cbo));			#collector current in A
print "Thus collector currents in case 1 and 2 are %g A , %g A respectively"%(Ic1,Ic2);

Thus collector currents in case 1 and 2 are 0.01301 A , 0.01454 A respectively

Example 13.14 Page No : 391

In [16]:
#INPUT DATA
deltaIe = 1*10**-3;			#change in emitter current in A
deltaIc = 0.99*10**-3;			#change in collector current in A
#CALCULATIONS
a = (deltaIc/deltaIe);			#current gain of the transistor
print "Thus current gain of the transistor is %1.2f"%(a);

Thus current gain of the transistor is 0.99

Example 13.15 Page No : 391

In [17]:
#INPUT DATA
b = 100.;			#common-emitter DC current gain
#CALCULATIONS
a = (b/(1+b));			#common-base DC current gain
print "Thus common-base DC current gain is %1.2f"%(a);

Thus common-base DC current gain is 0.99

Example 13.16 Page No : 391

In [18]:
#INPUT DATA
deltaIe = 1*10**-3;			#change in emitter current in A
deltaIc = 0.995*10**-3;			#change in collector current in A
#CALCULATIONS
a = deltaIc/deltaIe;			#common-base DC current gain
b = a/(1-a);			#common-emitter DC current gain
print "Thus common-base DC current gain and common-emitter DC current gain are %1.3f and %1.0f respectively"%(a,b);

Thus common-base DC current gain and common-emitter DC current gain are 0.995 and 199 respectively

Example 13.17 Page No : 391

In [19]:
#INPUT DATA
b = 49.;			#common-emitter DC current gain
Ie = 3*10**-3;			#emitter current in A
#CALCULATIONS
a = b/(1+b);			#common-base DC current gain
Ic = a*Ie;			#collector current in A
print "Thus common-base DC current gain and ccollector current are %1.2f and %g A respectively"%(a,Ic);

Thus common-base DC current gain and ccollector current are 0.98 and 0.00294 A respectively

Example 13.18 Page No : 393

In [20]:
#INPUT DATA
Ib = 15.*10**-3;			#base current in A
b = 150.;			#common-emitter DC current gain
#CALCULATIONS
Ic = b*Ib;			#collector current in A
Ie = Ic+Ib;			#emitter current in A
a = b/(1+b);			#common-base DC current gain
print "Thus collector current, emitter current and common-base DC current gain are %g A,  %g A  and %1.4f  respectively"%(Ic,Ie,a);

Thus collector current, emitter current and common-base DC current gain are 2.25 A,  2.265 A  and 0.9934  respectively

Example 13.19 Page No : 393

In [21]:
#INPUT DATA
Vcc = 10;			#collector to collector voltage in volts
Vbb = 4;			#base to base voltage in volts
Rb = 200*10**3;			#base resistance in ohms
Rc = 2*10**3;			#collector resistance in ohms
Vbe = 0.7;			#base to emitter voltage in volts
b = 200;			#common-emitter DC current gain
#CALCULATIONS
Ib = (Vbb-Vbe)/(Rb);			#base current in A
Ic = b*Ib;			#collector current in A
Ie = Ic+Ib;			#emitter current in A
Vce = Vcc-(Ic*Rc);			#collector to emitter voltage in volts
print "Thus collector current, emitter current and base currents are %g A, %g A and %g A respectively"%(Ib,Ic,Ie);
print "collector to emitter voltage is %1.1f V"%(Vce)

Thus collector current, emitter current and base currents are 1.65e-05 A, 0.0033 A and 0.0033165 A respectively
collector to emitter voltage is 3.4 V

Example 13.20 Page No : 394

In [22]:
#INPUT DATA
a = 0.99;			#common-base DC current gain
Icbo = 5*10**-6;			#current in A
Ib = 20*10**-6;			#current in A
#CALCULATIONS
Ic = ((a*Ib)/(1-a))+(Icbo/(1-a));			#collector current in A
Ie = Ib+Ic;			#emitter current in A
print "collector and  emitter currents are %g A and %g A respectively"%(Ic,Ie)

collector and  emitter currents are 0.00248 A and 0.0025 A respectively

Example 13.21 Page No : 394

In [23]:
#INPUT DATA
Icbo = 0.2*10**-6;			#current in A
Iceo = 18*10**-6;			#current in A
Ib = 30*10**-6;			#current in A
#CALCULATIONS
a = 1-(Icbo/Iceo);			#common-base DC current gain
b = (Iceo/Icbo)-1;			#common-emitter DC current gain
Ic = (b*Ib)+((1+b)*(Icbo));			#collector current in A
print "Thus common-base DC current gain and common-emitter DC current gain are %1.3f and %d respectively"%(a,b)

Thus common-base DC current gain and common-emitter DC current gain are 0.989 and 89 respectively

Example 13.22 Page No : 394

In [24]:
#INPUT DATA
a = 0.99;			#common-base DC current gain
Icbo = 50*10**-6;			#current in A
Ib = 1*10**-3;			#current in A
#CALCULATIONS
Ic = ((a*Ib)/(1-a))+(Icbo/(1-a));			#collector current in A
Ie = Ic+Ib;			#emitter current in A
print "Thus emitter current is %g A"%(Ie)

Thus emitter current is 0.105 A