# Chapter 9 - Multistage Amplifier¶

## PageNumber 424 example 1¶

In [1]:
from math import sqrt
from __future__ import division
#(1) frequency
freque=100*10**3*sqrt(2**(1/3)-(1))
frequ2=100*10**3/sqrt(2**(1/3)-(1))
print "frequency1   =   %0.2f"%((freque)),"hertz"
print "frequency2   =   %0.2f"%((frequ2)),"hertz"
#(2)frequency
freq11=100*10**6##hertz
freq12=150*10**6##hertz
freq13=200*10**6##hertz
freq21=100*10**3##hertz
freq22=150*10**3##hertz
freq23=200*10**3##hertz
frequ1=sqrt(freq11**2+freq12**2+freq13**2)
print "frequency   =   %0.2f"%((frequ1)),"hertz"##correction in the book 269.25mega hertz
frequ1=1/sqrt((1/(freq21**2))+(1/(freq22**2))+(1/(freq23**2)))
print "frequency   =   %0.2f"%((frequ1)),"hertz"##correction in the book

frequency1   =   50982.45 hertz
frequency2   =   196145.92 hertz
frequency   =   269258240.36 hertz
frequency   =   76822.13 hertz


## PageNumber 424 example 2¶

In [2]:
freque=60##hertz
frequ1=freque*0.484
cb=1/(frequ1*2*3.14*10**3)
print "coupling capacitance   =   %0.2e"%((cb)),"/r"

coupling capacitance   =   5.48e-06 /r


## PageNumber 425 example 3¶

In [3]:
g=10*10**-3##ampere per volt
rd=5.5*10**3##ohm
rg=1*10**6##ohm
#(1) cb frequency 1decibel to 10hertz
ri=rg
r1=(rd*8*10**3)/(rd+8*10**3)
cb=10**-6/(3.14*5.07)
#(2) cb
cb=(cb*(5)/(3.52))
#(3) gain
a1=g**2*(3.26**2)
print "gain of each stage   =   %0.2e"%((a1))
#correction required in the book

cb   =   6.28e-08 farad
gain of each stage   =   1.06e-03


## PageNumber 427 example 4¶

In [4]:
freque=40*10**3##hertz
frequ1=freque/0.507
print "upper frequency   =   %0.2f"%((frequ1)),"hertz"
frequ1=freque/1.96
print "lower frequency   =   %0.2f"%((frequ1)),"hertz"

upper frequency   =   78895.46 hertz
lower frequency   =   20408.16 hertz


## PageNumber 427 example 5¶

In [5]:
from math import log10
g=2.6*10**-3##ampere per volt
rd=7.7*10**3##ohm
rd1=12*10**3##ohm
#(1) voltage gain
volgai=g*((1/rd)+1/rd1+1/(1*10**3))
volgai=(20*(log10(10.8)))*3
print "overal voltage gain   =   %0.2f"%((volgai)),"decibel"##correction in the book
#(2) lower frequency
r=rd*rd1/(rd+rd1)
freque=1/((2*3.14)*(r+1*10**6)*cb)
print "lower frequency of each   =   %0.2f"%((freque)),"hertz"
#(3) overal lower frequency
freque=freque*1.96
print "lower frequency overal   =   %0.2f"%((freque)),"hertz"

overal voltage gain   =   62.01 decibel
lower frequency of each   =   31.70 hertz
lower frequency overal   =   62.13 hertz


## PageNumber 429 example 6¶

In [6]:
hfe=50
hie=1.1*10**3##ohm
#(1) gain
r1=2*10**3##ohm
volgai=-hfe*r1/(hie)
r11=25*10**3*hie/(25*10**3+hie)
r11=r1*r11/(r1+r11)
volga1=-hfe*r11/hie
volgai=volgai*volga1
print "voltage gain   =   %0.2f"%((volgai))
freque=20##hertz
ri=25*10**3*hie/(25*10**3+hie)
cb=1/(2*3.14*(ri+r1)*(freque))
cb=1/(2*3.14*3.05*10**3*10/3.14)

voltage gain   =   2851.60

from math import atan, degrees

theta1   =   5.71