# Chapter 04 : Bipolar junction transistors¶

## Example 4.1, Page No 153¶

In [1]:
import math
#initialisation of variables
Ib=100*10**-6

#Calculations
print("value of Ic is %3.3fA " %Ic)

#Results
print(" value of Ie is %3.3fA " %Ie)
print("The value of Bdc = %.2f " %Bdc)

value of Ic is 0.005A
value of Ie is 0.005A
The value of Bdc = 49.00


## Example 4.2, Page No 153¶

In [2]:
import math

#initialisation of variables
Ic=1.0*10**-3
Ib=25.0*10**-6

#Calculations
Bdc=Ic/Ib
Ie=Ic+Ib
Ic=5
Ib=Ic/Bdc

print("The new base current = %.2f mA" %(Ib*10**3))

The new base current = 125.00 mA


## Example 4.3 Page No 157¶

In [3]:
import math

#initialisation of variables

Bdc=80.0
Bac=Bdc
Vcc=18.0
R1=10.0*10**3

#Calculations
Ib=15.0*10**-6#for Vb=.7
Ic=Bdc*Ib
Vc=Vcc-(Ic*R1)

#Results
print("dc collector voltage is %dV " %Vc)
print(" when vi=50mV")
Ib=3.0*10**-6
Vi=50.0*10**-3
Ic=Bdc*Ib
Vo=Ic*R1
Av=Vo/Vi

#Results
print("Current voltage is %.1f V " %(Av))

dc collector voltage is 6V
when vi=50mV
Current voltage is 48.0 V


## Example 4.4, Page No 160¶

In [4]:
import math
#initialisation of variables
Vcc=5.0
Vce=.2
R2=4.7*10**3
Vi=2
Vbe=.7

#Calculations
R1=12.0*10**3
Ic=(Vcc-Vce)/R2
Ib=(Vi-Vbe)/R1
hFE=Ic/Ib

#Results
print("Transistor current gain is %.2f V " %(hFE))

Transistor current gain is 9.43 V


## Example 4.6 Page No 169¶

In [5]:
import math
#initialisation of variables
Vbe=.7
Vce=-6

#Calculations
Ib=20.0*10**-6
Ic=2.5*10**-3#from output characteristics
Bdc=Ic/Ib

#Results
print("The value of Bdc is %.1f V " %Bdc)

The value of Bdc is 125.0 V