Chapter 8 Amplifiers

Ex8_1 PG-8.3

In [1]:
from __future__ import division
from math import log10
Av=100##voltage gain
G=20*log10(Av)##gain in decibel
print "\n Therefore gain in decibel=%.0f dB \n"%(G)

 Therefore gain in decibel=40 dB

Ex8_2 PG-8.5

In [1]:
from math import sqrt
Av=200##gain at cut-off frequencies
Avm=Av*sqrt(2)##maximum voltage gain
print "\n Therefore maximum voltage gain=%.2f \n"%(Avm)

 Therefore maximum voltage gain=282.84

Ex8_3 PG-8.6

In [4]:
from math import sqrt
Amid=100##mid-band gain
f1=1e3##loer cut-off frequency
f=20##frquency at which the gain of the amplifier should be found
A=Amid/sqrt(1+(f1/f)**2)
print "\n Therefore  the gain of the amplifier at f = 20Hz is %.0f \n"%(A)

 Therefore  the gain of the amplifier at f = 20Hz is 2

Ex8_4 PG-8.7

In [5]:
from math import sqrt
G=200##3dB gain
f2=20e3##higher cut-off frequency
Amid=G*sqrt(2)##mid-band gain
f=100e3##frquency at which the gain of the amplifier should be found
A=Amid/sqrt(1+(f/f2)**2)
print "\n Therefore  the gain of the amplifier at f=100kHz is %.2f \n"%(A)
#in the  book the answer for the gain is 115.47 which is wrong 
#the corect answer is 55.47

 Therefore  the gain of the amplifier at f=100kHz is 55.47