Chapter 5: Bipolar Transistor and Related Devices

Example 5.1 Page 136

In [1]:
#initialisation of variable
from math import *
IEp=3.0000000;#mA
IEn=.0100000;#mA
ICp=2.9900000;#mA
ICn=.0010000;#mA

#calculation
E=IEp/(IEp+IEn);#emitter efficiency
At=ICp/IEp;#base transport factor
Ao=E*At;#common-base current
IE=IEp+IEn;
IC=ICp+ICn;
Icbo=round(IC,6)-round((Ao*IE),6);#ICBO

#result
print"emitter efficiency is",round(E,4)
print"base transport factor is",round(At,4)
print"common-base current is",round(Ao,4)
print "ICBO is",round(Icbo*100,4),"micro-amp"
print"(slight change in the answer due to round off error)"

emitter efficiency is 0.9967
base transport factor is 0.9967
common-base current is 0.9934
ICBO is 0.1 micro-amp
(slight change in the answer due to round off error)

Example 5.2 Page 141

In [2]:
#initialisation of variable
from math import *
C1=10**19;#concentration
C2=10**17;#concentration
C3=5*10**15;#concentration
T1=10**-8;#s
T2=10**-7;#s
T3=10**-6;#s
A=.05;#area
V=.6;#V
De=1;
Dp=10;
Dc=2;
W=.5;#width
n=9.65*10**9;#constant
q=1.6*10**-19;#charge

#calculation
Lp=(Dp*T2)**.5;#base region
Le=(De*T1)**.5;#emitter region
P=n**2/C2;
N=n**2/C1;
Iep=q*A*N*e**23.17*10**5/W;#A
Icp=Iep;#A
Ien=q*A*N*(e**23.17-1)*100;#A
Ao=Icp/(Iep+Ien);#current

#result
print"common-base current gain is",round(Ao,4)

common-base current gain is 0.9995

Example 5.3 Page 145

In [3]:
#initialisation of variable
from math import *
IEp=3.0000000;#mA
IEn=.0100000;#mA
ICp=2.9900000;#mA
ICn=.0010000;#mA
Icbo=.87e-6;#ICBO

#calculation
E=IEp/(IEp+IEn);#emitter efficiency
At=ICp/IEp;#base transport factor
Ao=E*At;#common-base current
IE=IEp+IEn;#A
IC=ICp+ICn;#A
B=Ao/(1.0000-Ao)+1;
Iceo=(B+1)*Icbo;#A

#result
print"common-emitter current gain is",round(B,4)
print"ICEO is",round(Iceo*10**4,2)/10**4,"A"

common-emitter current gain is 150.5
ICEO is 0.000132 A

Example 5.4 Page 152

In [4]:
#initialisation of variable
from math import *
E1=1.62;#eV
E2=1.42;#eV
B1=1.42;#eV
B2=1.42;#eV
De=10**18;
Db=10**15;

#xalculation
B=e**((E1-E2)/.0259);#beta
Nb=B*Db;#doping

#result
print"improvement is",round(B,0),"times"
print"increase of base doping is",round(Nb,0),"cm^-3"

improvement is 2257.0 times
increase of base doping is 2.25748744092e+18 cm^-3

Example 5.5 Page159

In [5]:
#initialisation of variable
from math import *
I1=.4;#mA
I2=.6;#mA
a1=.01;#alpha1
a2=.9999;#alpha2

#calculation
Ia=(I1+I2)/(1-a1);#forward blocking character 1
Ib=(I1+I2)/(1-a2);#forward blocking character 2

#result
print"forward blocking character 1 is",round(Ia,2),"mA"
print"forward blocking character 2 is",round(Ib/1000,2),"A"

forward blocking character 1 is 1.01 mA
forward blocking character 2 is 10.0 A