Chapter 7 Small Signal Midfrequency Fet And Triode Amplifiers

Example 7.1 , Page no:207

In [1]:
import math
from __future__ import division

#initialisation of variables
Vgs=2

#CALCULATIONS
Did=(3.3-0.3)*10**-3
gm=Did/Vgs*1000
Dvds=20-5
Did1=(1.6-1.4)*10**-3
rds=Dvds/Did1/1000
Did2=(2-1)*10**-3
Dvgs=-1.75-(-2.4)
gm1=Did2/Dvgs*1000  

#RESULTS
print"The value of gm=",round(gm,3),"mS";
print"The value of rds=",round(rds,3),"kOhm";
print"The value of gm=",round(gm1,3),"mS";

The value of gm= 1.5 mS
The value of rds= 75.0 kOhm
The value of gm= 1.538 mS

Example 7.3 , Page no:208

In [2]:
import math
from __future__ import division

#initialisation of variables
Rl=14*10**3
rds=40*10**3
Rf=5*10**6
gm=1*10**-3

#CALCULATIONS
Av=((Rl*rds*(1-Rf*gm))/(Rf*rds+Rl*rds+Rl*Rf))
Zin=(Rf/(1-Av))/1000
Ai=(Av*Zin)/Rl*1000

#RESULTS
print"The value of Av=",round(Av,3);
print"The value of Zin=",round(Zin,3),"kOhm";
print"The value of Ai=",round(Ai,3);

The value of Av= -10.347
The value of Zin= 440.651 kOhm
The value of Ai= -325.668

Example 7.4 , Page no:209

In [3]:
import math
from __future__ import division

#initialisation of variables
R1=200*10**3
R2=800*10**3
Rg=160*10**3
r1=5*10**3
Av=-1.88
Rl=2*10**3

#CALCULATIONS
Zin=(R1*R2/(R1+R2))/1000
vgs=Rg/(Rg+r1)
Ai=(Av*(Rg+r1))/Rl

#RESULTS
print"The value of Zin=",round(Zin,3),"Kohm";
print"The value of vgs=",round(vgs,3),"vi";
print"The value of ai=",round(Ai,3),"vi";

The value of Zin= 160.0 Kohm
The value of vgs= 0.97 vi
The value of ai= -155.1 vi

Example 7.7 , Page no:211

In [4]:
import math
from __future__ import division

#initialisation of variables
Rd=2
Rl=4
Rg=160
r1=5
rds=30
Rs=3

#CALCULATIONS
m=2*10**-3
Rg1=30*10**3
Av=(-m*Rg*Rd*Rl)/((Rg+r1)*((Rd+Rl)*(rds+(m+1)*Rs+Rd*Rl)))*1000

#RESULTS
print"The value of Av=",round(Av,3);

The value of Av= -0.063

Example 7.10 , Page no:213

In [5]:
import math
from __future__ import division

#initialisation of variables
Rg=100 #kΩ
ri=5
gm=0.0025
rds=25
Rd=2 #kΩ
Rl=2 #kΩ

#CALCULATIONS
vgs=(Rg/(Rg+ri))
Req=(rds*Rd*Rl*10**3)/(2*Rl*Rd+rds*(Rl+Rd))
Av=-2*gm*vgs*Req
Ai=((Av*(Rg+ri))/Rl)
R0=(Rd*rds)/(2*Rd+rds)

#RESULTS
print"The value of vgs=",round(vgs,3),"vi";
print"The value of Req=",round(Req,3),"Kohm";
print"The value of Av=",round(Av,3)
print"The value of Ai=",round(Ai,3)
print"The value of R0=",round(R0,3),"Kohm";

The value of vgs= 0.952 vi
The value of Req= 925.926 Kohm
The value of Av= -4.409
The value of Ai= -231.481
The value of R0= 1.724 Kohm

Example 7.11 , Page no:214

In [6]:
import math
from __future__ import division

#initialisation of variables
gm=0.002

#CALCULATIONS
rds=30*10**3
Rs2=1.2*10**3
Rl=1*10**3 #kΩ
Rg=1*10**6 #kΩ
Req=1/((1/rds)+(1/Rs2)+(1/Rl))
Av=((gm*Rg+1)*Req)/(Rg+(gm*Rg+1)*Req)
Ai=(Av*Rg/((1-Av)*Rl))
Rin=Rg/(1-Av)/10**6
R0=1/(1/Rs2+1/rds+1/Rg+gm)

#RESULTS
print"The value of Req=",round(Req,3)
print"The value of Av=",round(Av,3)
print"The value of Ai=",round(Ai,3)
print"The value of Rin=",round(Rin,3),"mOhm";
print"The value of R0=",round(R0,3),"Ohm";

The value of Req= 535.714
The value of Av= 0.517
The value of Ai= 1071.964
The value of Rin= 2.072 mOhm
The value of R0= 348.716 Ohm

Example 7.12 , Page no:215

In [7]:
import math
from __future__ import division

#initialisation of variables
gm=1.5*10**-3
rds=75*10**3
Rd=3*10**3 #kΩ
rds=75*10**3

#CALCULATIONS
vds=-(gm*rds*Rd)/(rds+Rd)
Vdsm=-1*vds #V
idm=(gm+(Vdsm/rds))*1000   

#RESULTS
print"The value of vds=",round(vds,3),"vgs";
print"The value of idm=",round(idm,3),"mA";

The value of vds= -4.327 vgs
The value of idm= 1.558 mA

Example 7.18 , Page no:219

In [8]:
import math
from __future__ import division

#initialisation of variables
vp=100 #v
vg=-4

#CALCULATIONS
ip=15*10**-3 #mA
k=(ip/(vp**(3/2)))*10**6
m=-(vp/vg)

#RESULTS
print"The value of k=",round(k,3),"mA/v^3/2";
print"The value of m=",round(m,3);

The value of k= 15.0 mA/v^3/2
The value of m= 25.0

Example 7.20 , Page no:219

In [9]:
import math
from __future__ import division

#initialisation of variables
dvp=218-152
dip=(14.7-8.1)*10**-3

#CALCULATIONS
rp=dvp/dip/1000 #kΩ
dvg=-2-(-6)
gm=dip/dvg*1000 #mS

#RESULTS
print"The value of rp=",round(rp,3),"kOhm";
print"The value of gm=",round(gm,3),"mS";

The value of rp= 10.0 kOhm
The value of gm= 1.65 mS

Example 7.22 , Page no:220

In [10]:
import math
from __future__ import division

#initialisation of variables
Vpp=300 #V
Vgq=4 #V
Rl=11.6*10**3 #Ω
Vpm=34 #V
Vgm=2

#CALCULATIONS
Av=-(2*Vpm/2*Vgm)
dvp=202-168
dip=(15-8)*10**-3
rp=dvp/dip/1000 #kΩ
dip1=(15.5-6.5)*10**-3
dvg=-3-(-5)
gm=dip1/dvg*1000 #ms
m=21.87
Rl=11.6 #Ω
Av=-(m*Rl*10**3)/((Rl+rp)*10**3) #Voltage gain

#RESULTS
print"The value of rp=",round(rp,3),"kOhm";
print"The value of gm=",round(gm,3),"ms";
print"The value of Av=",round(Av,3);

The value of rp= 4.857 kOhm
The value of gm= 4.5 ms
The value of Av= -15.415