Chapter 3 Characteristics of Bipolar Junction Transistors

Example 3.1 , Page no:81

In [1]:
import math
from __future__ import division

#initialisation of variables
betaa=50
Ic=1.2 #mA

#CALCULATIONS
Iceo=3*10**-3 #mA
Ib=((Ic-Iceo)/betaa)*1000 #mA
IE=(Ic)-(Ib*10**-3)

#RESULTS
print"Ib =",round(Ib,2),"X 10^-3 mA";
print"IE =",round(IE,2),"m";

Ib = 23.94 X 10^-3 mA
IE = 1.18 m

Example 3.2 , Page no:83

In [2]:
import math
from __future__ import division

#initialisation of variables
betaa=100
Ib=0 #mA
Icbo=5 #V  #mA
Ib=40

#CALCULATIONS
Iceo=(betaa+1)*Icbo #mA
Ic=((betaa*Ib)+(betaa+1)*Icbo)/1000

#RESULTS
print"When Ib =0 Iceo =",round(Iceo,3),"mA";
print"When Ib =40 Ic =",round(Ic,3),"mA";

When Ib =0 Iceo = 505.0 mA
When Ib =40 Ic = 4.505 mA

Example 3.3 , Page no:83

In [3]:
import math
from __future__ import division

#initialisation of variables
alpha=0.98

#CALCULATIONS
betaa=alpha/(1-alpha)
Icbo=(5*10**-3) #mA
Iceo=(betaa+1)*Icbo #mA
Ibq=100*10**-3
Icq=(betaa*Ibq)+Iceo
Ieq=Icq+Ibq

#RESULTS
print"Iceo =",round(Iceo,3),"mA";
print"Icq =",round(Icq,3),"mA";
print"Ieq =",round(Ieq,3),"mA";

Iceo = 0.25 mA
Icq = 5.15 mA
Ieq = 5.25 mA

Example 3.4 , Page no:83

In [4]:
import math
from __future__ import division

#initialisation of variables
alpha=0.98

#CALCULATIONS
betaa=alpha/(1-alpha)
Icq=1.47 #mA
Ieq=Icq/alpha #mA

#RESULTS
print"Beta =",round(betaa,3);
print"Ieq =",round(Ieq,3),"mA";

Beta = 49.0
Ieq = 1.5 mA

Example 3.5 , Page no:84

In [5]:
import math
from __future__ import division

#initialisation of variables
Vbb=6 #V
Vbeq=0.7 #V
Ibq=40 #10^-6

#CALCULATIONS
Rb=((Vbb-Vbeq)/Ibq)*1000

#RESULTS
print"Rb =",round(Rb,3),"k ohm";

Rb = 132.5 k ohm

Example 3.6 , Page no:84

In [6]:
import math
from __future__ import division

#initialisation of variables
b=100

#CALCULATIONS
a=b/(b+1)
Ibq=20 #10**-6 #mA
Icq=(b*Ibq)/1000 #mA
Ieq=Icq/a #mA

#RESULTS
print"Icq =",round(Icq,3),"mA";
print"Ieq =",round(Ieq,3),"mA";

Icq = 2.0 mA
Ieq = 2.02 mA

Example 3.7 , Page no:85

In [7]:
import math
from __future__ import division

#initialisation of variables
b=80

#CALCULATIONS
a=b/(b+1)
Ibq=40 #10**-6 #mA
Ieq=(Ibq/(1-a))/1000 #mA
Icq=(b*Ibq)/1000

#RESULTS
print"Ieq =",round(Ieq,3),"mA";
print"Icq =",round(Icq,3),"mA";

Ieq = 3.24 mA
Icq = 3.2 mA

Example 3.8 , Page no:85

In [8]:
import math
from __future__ import division

#initialisation of variables
Vcc=14 #V
Icq=2.25 #mA

#CALCULATIONS
Rc=(14/(6.5*10**-3))/1000 #kΩ
Ibq=20*10**-3 #mA
Ieq=Icq+Ibq #mA
b=Icq/Ibq

#RESULTS
print"Ieq =",round(Ieq,3),"mA";
print"Beta =",round(b,3),"mA";

Ieq = 2.27 mA
Beta = 112.5 mA

Example 3.9 , Page no:85

In [9]:
import math
from __future__ import division

#initialisation of variables
b=70
Vcc=15 #V
Vbeq=0.7 #V
Iceo=1.42 #mA
Rb=500 #*10^3   #kΩ

#CALCULATIONS
Ibq=((Vcc-Vbeq)/Rb)*1000
Icq=((b*Ibq/1000)+Iceo)

#RESULTS
print"Ibq =",round(Ibq,3),"mA";
print"Icq =",round(Icq,3),"mA";

Ibq = 28.6 mA
Icq = 3.422 mA

Example 3.12 , Page no:87

In [10]:
import math
from __future__ import division

#initialisation of variables
Vceq=-6.4 #V
Vbeq=-0.3 #V
Vee=2
Ieq=3

#CALCULATIONS
Vcbq=Vceq-Vbeq #V
Re=((Vee+Vbeq)/Ieq)*1000

#RESULTS
print"Vcbq =",round(Vcbq,3),"V";
print"Re =",round(Re,3),"Ohm";

Vcbq = -6.1 V
Re = 566.667 Ohm

Example 3.13 , Page no:88

In [11]:
import math
from __future__ import division

#initialisation of variables
Vcc=12 #V
Vceq=6 #V
hf=100
Rc=2 #*10^3     #kΩ
Vbeq=0.7

#CALCULATIONS
Ibq=((Vcc-Vceq)/((hf+1)*Rc))*1000
Rf=((Vceq-Vbeq)/Ibq)*1000

#RESULTS
print"Ibq =",round(Ibq,3),"mA";
print"Rf =",round(Rf,3),"Ohm";

Ibq = 29.703 mA
Rf = 178.433 Ohm

Example 3.16 , Page no:89

In [12]:
import math
from __future__ import division

#initialisation of variables
b=80
Ibq=30

#CALCULATIONS
a=(b/(b+1))
Icq=Ibq*b/1000
Ieq=(Icq/a)

#RESULTS
print"Icq =",round(Icq,3),"mA";
print"Ieq =",round(Ieq,3),"mA";

Icq = 2.4 mA
Ieq = 2.43 mA

Example 3.19 , Page no:91

In [13]:
import math
from __future__ import division

#initialisation of variables
b=50
Vbeq=0.3 #V
Vcc=12 #v
Vs=2 #v
Rc=4 #Kohm
Rs=100 #Kohm
Vce=0.2

#CALCULATIONS
Icq=(Vcc-Vce)/Rc
Rb=((Vcc-Vbeq)/(Icq/b))

#RESULTS
print"Icq =",round(Icq,3),"mA";
print"Rb =",round(Rb,3),"Ohm";

Icq = 2.95 mA
Rb = 198.305 Ohm

Example 3.20 , Page no:91

In [14]:
import math
from __future__ import division

#initialisation of variables
b=50
b2=50
Vce=6 #V
Re=1 #kΩ
Vcc=12 #v   #V

#CALCULATIONS
Ieq2=(Vcc-Vce)/Re
Ibq2=(Ieq2/((b+1)*(b2+1)))*1000

#RESULTS
print"Ieq2 =",round(Ieq2,3),"mA";
print"Ibq2 =",round(Ibq2,3),"mA";

Ieq2 = 6.0 mA
Ibq2 = 2.307 mA

Example 3.23 , Page no:94

In [15]:
import math
from __future__ import division

#initialisation of variables
b=80
Ibq=30 #mA

#CALCULATIONS
a=(b/(b+1))
Icq=Ibq*b/1000 #mA
Ieq=(Icq/a)

#RESULTS
print"Icq =",round(Icq,3),"mA";
print"Ieq =",round(Ieq,3),"OmA";

Icq = 2.4 mA
Ieq = 2.43 OmA

Example 3.26 , Page no:96

In [16]:
import math
from __future__ import division

#initialisation of variables
b=100
Vbeq=0.7 #V
Vcc=15 #V
Re=300 #kΩ
Rc=500 #kΩ

#CALCULATIONS
Icq=((Vcc)/(2*(Re+Rc)))*1000
Rb=(b*Re/10)/1000
Vbb=Vbeq+Icq*(1.1*Re)/1000
R1=Rb/(1-Vbb/Vcc)
R2=Rb*(Vcc/Vbb)

#RESULTS
print"Icq =",round(Icq,3),"mA";
print"Rb =",round(Rb,3),"Kohm";
print"Vbb =",round(Vbb,3),"V";
print"R1 =",round(R1,3),"Kohm";
print"R2 =",round(R2,3),"Kohm";

Icq = 9.375 mA
Rb = 3.0 Kohm
Vbb = 3.794 V
R1 = 4.016 Kohm
R2 = 11.862 Kohm

Example 3.32 , Page no:99

In [17]:
import math
from __future__ import division

#initialisation of variables
Vcc=12 #v
Vbeq=0.7 #v

#CALCULATIONS
Re=1*10**3 #kΩ
Icq=6*10**3 #mA
Ibq=50*10**-3 #mA
b=Icq/Ibq

#RESULTS
print"B =",round(b,3),"mA";

B = 120000.0 mA