# Chapter - 27 : FEEDBACK AMPLIFIERS¶

## Ex 27.1 Pg 819¶

In [1]:
from __future__ import division

AV=400#
beta=0.1#
AV1=AV/(1+beta*AV)#
print "Av1=%0.2f "%(AV1)#

Av1=9.76


## Ex 27.2 Pg 820¶

In [2]:
from __future__ import division

AV=1000#
AV1=10#
beta=((AV/AV1)-1)/AV#
print "beta=%0.2f"%beta

beta=0.10


## Ex 27.3 Pg 820¶

In [3]:
from __future__ import division

AV=100#
AV1=20#
beta=((AV/AV1)-1)/AV#
print "beta=%0.2f"%beta

beta=0.04


## Ex 27.4 Pg 820¶

In [4]:
from __future__ import division

Vo=12.5#
Vin1=1.5#
Vin=0.25#
AV=Vo/Vin#
print "Av=%0.2f"%(AV)#
AV1=Vo/Vin1#
beta=((AV/AV1)-1)/AV#
print "beta=%0.2f"%beta

Av=50.00
beta=0.10


## Ex 27.5 Pg 821¶

In [9]:
from __future__ import division

AV=60#
AV1=80#
#80=AV/(1-BETA*AV)
beta=((AV1/AV)-1)/AV1#
print "beta=%0.2e"%beta
beta=1/AV#
print "beta=%0.2f"%beta

beta=4.17e-03
beta=0.02


## Ex 27.6 Pg 821¶

In [8]:
from __future__ import division

AV1=100#
Vin=50*10**-3#
Vin1=0.6#
Vo=AV1*Vin1#
Av=Vo/Vin#
print "Av=%0.2f"%(Av)
beta=((Av/AV1)-1)/Av#
print 'beta=%0.2e'%(beta)

Av=1200.00
beta=9.17e-03


## Ex 27.7 Pg 821¶

In [10]:
from __future__ import division

Av=800#
B=0.05#
dAvbyAv=20#
a=dAvbyAv*(1/(1+B*Av))#
print 'a=%0.2f %%'%a

a=0.49 %


## Ex 27.8 Pg 821¶

In [13]:
from __future__ import division

AV1=100#
A=0.01#
B=0.2#
C=B/A#
AV=AV1*C#
beta=C/AV#
print "beta=%0.3f"%beta

beta=0.010


## Ex 27.9 Pg 822¶

In [14]:
from __future__ import division

AV=100#
BW=200*10**3#
beta=0.05#
BW1=(1+beta*AV)*BW#
print 'BW1=%0.2f kHZ'%(BW1*10**-3)
AV1=AV/(1+beta*AV)#
print "AV1=%0.2f "%(AV1)#
#1*10**6=(1+beta1*AV)*BW#
beta1=(((1*10**6)/(200*10**3))-1)/100#
print "beta1=%0.2f"%beta1

BW1=1200.00 kHZ
AV1=16.67
beta1=0.04


## Ex 27.10 Pg 822¶

In [15]:
from __future__ import division

AV=1500#
BW=4*10**6#
AV1=150#
beta=((1500/150)-1)/1500#
print "beta=%0.2f"%beta
BW1=(1+beta*AV)*BW#
print 'BW1=%0.2f MHZ'%(BW1*10**-6)

beta=0.01
BW1=40.00 MHZ


## Ex 27.11 Pg 822¶

In [16]:
from __future__ import division

Rin=4.2*10**3#
AV=220#
beta=0.01#
Ri=(1+beta*AV)*Rin#
print 'Ri=%0.2f kohm'%(Ri*10**-3)
F1=1.5*10**3#
FC1=F1/(1+beta*AV)#
print 'FC1=%0.2f HZ '%FC1
F2=501.5*10**3#
FC2=(1+beta*AV)*F2#
print 'FC2=%0.2f HZ '%FC2

Ri=13.44 kohm
FC1=468.75 HZ
FC2=1604800.00 HZ


## Ex 27.12 Pg 822¶

In [17]:
from __future__ import division

AV=1000#
f1=50#
f2=200*10**3#
D=0.05#
beta=0.01#
AV1=AV/(1+beta*AV)#
print "Av1=%0.2f"%AV1
fl1=f1/(1+beta*AV)#
print 'fl1=%0.2f HZ'%(fl1)
fu2=(1+beta*AV)*f2#
print 'fu2=%0.2f MHZ'%(fu2*10**-6)
D1=D/(1+beta*AV)#
print 'D1=%0.2f %%'%(D1*100)

Av1=90.91
fl1=4.55 HZ
fu2=2.20 MHZ
D1=0.45 %


## Ex 27.13 Pg 823¶

In [18]:
from __future__ import division

AV=100#
RDN=0.8#
#0.8=1-(1/(1+beta*AV))#
beta=((1/0.2)-1)/100#
print "beta=%0.2f "%beta
AV1=AV/(1+beta*AV)#
print "AV1=%0.2f "%AV1

beta=0.04
AV1=20.00


## Ex 27.14 Pg 823¶

In [20]:
from __future__ import division

AV=300#
Ri=1.5*10**3#
R0=50*10**3#
b=1/15#
AV1=AV/(1+b*AV)#
print "AV1=%0.2f "%AV1
Ri1=(1+b*AV)*Ri##input resistance
print 'Ri1=%0.2f kohm'%(Ri1*10**-3)
Ri1=R0/(1+b*AV)##output resistance
print 'Ri1=%0.2f kohm'%(Ri1*10**-3)

AV1=14.29
Ri1=31.50 kohm
Ri1=2.38 kohm


## Ex 27.15 Pg 823¶

In [21]:
from __future__ import division

hfe=100#
hie=2*10**3#
Rc=470#
Re1=100#
Re2=100#
R1=15000#
R2=5600#
AV=(hfe*Rc)/hie#
print "AV=%0.2f"%(AV)
a=((R1*R2)/(R1+R2))#
Ri=(a*hie)/(a+hie)#
print 'Ri=%0.2f ohm'%Ri
b=Re1/Rc#
AV1=AV/(1+b*AV)#
print "AV1=%0.2f"%(AV1)
Ri1=Ri*(1+b*AV)#
print 'Ri1=%0.2f ohm'%Ri1

AV=23.50
Ri=1341.85 ohm
AV1=3.92
Ri1=8051.12 ohm


## Ex 27.16 Pg 823¶

In [22]:
from __future__ import division

hfe=99#
hie=2*10**3#
hie1=2000#
hie2=2000#
Rc=22*10**3#
R4=100#
R1=220*10**3#
R2=22*10**3#
RC1=4.7*10**3#
R3=7.8*10**3#
Ri=hie#
a=(R1*R2)/(R1+R2)#
b=(a*Rc)/(a+Rc)#
R01=(b*hie1)/(b+hie1)
print 'R01=%0.2f kohm'%(R01*10**-3)
Ri2=hie#
C=(R3+R4)#
R02=(RC1*C)/(RC1+C)
print 'R02=%0.2f kohm'%(R02*10**-3)
AV1=hfe*R01/hie#
AV2=hfe*R02/hie#
AV=AV1*AV2#
bta=R4/(R3+R4)#
Ri1=Ri*(1+bta*AV)#
print 'Ri1=%0.2f kohm'%(Ri1*10**-3)
RO2=R02/(1+bta*AV)#
print 'RO2=%0.2f ohm'%RO2
AV1=AV/(1+bta*AV)#
print "AV1=%0.2f"%AV1

R01=1.68 kohm
R02=2.95 kohm
Ri1=308.99 kohm
RO2=19.07 ohm
AV1=78.49