Chapter 20: Field-effect Transistors

Example 20.1, Page

import math

#Introduction
gm=2*10**-3
rd=2*10**3                         #resistance in ohm
C=10**-6                           #capacitance in farad
R=10**6                            #resistance in ohm


#Calculation
G=-gm*rd                             #Small signal voltage gain
fc=1/(2*math.pi*C*R)                 #frequency in Hz

#Result
print'Small signal voltage gain = %d '%G
print'Low frequency cut off = %.2f Hz'%fc

Small signal voltage gain = -4 
Low frequency cut off = 0.16 Hz

Example 20.2, Page

import math

#Introduction
idd=4*10**-3                        #current in ampere
vo=8                               #voltage
vdd=12                             #voltage

#Calculation
Rd=vo*(vdd-idd)**-1

#Result
print'Rd = %.2f kOhm'%Rd          #wrong answer in textbook

Rd = 0.67 kOhm