Ch-12 : Large Signal Amplifiers

Page No. 414 Example 12.1.

In [1]:
RL=16*10**2 #in ohm
x1=RL*10**-3 # in k-ohm
print "RL'' = (N1/N2)**2 * RL =%0.2f kohm"%x1

RL'' = (N1/N2)**2 * RL =1.60 kohm

Page No. 414 Example 12.2.

In [2]:
x1=7200./8
print "(N1/N2)**2 = RL''/RL =%0.2f"%x1
x2=x1**0.5
print "N1/N2 =%0.2f"%x2
print "Hence, N1 : N2 = 30 : 1"

(N1/N2)**2 = RL''/RL =900.00
N1/N2 =30.00
Hence, N1 : N2 = 30 : 1

Page No. 415 Example 12.3.

In [5]:
print "(i) Series-fed load"
eta=(25.*14)/15. #in percentage
print "Overall efficiency,  eta = 25(Vmax-Vmin / Vmax) =%0.2f %%"%eta
print "(ii) Transformer-coupled load"
eta=50.*(14./16) #in percentage
print "Overall efficiency,  eta = 50*(Vmax-Vmin / Vmax+Vmin) =%0.2f %%"%eta

(i) Series-fed load
Overall efficiency,  eta = 25(Vmax-Vmin / Vmax) =23.33 %
(ii) Transformer-coupled load
Overall efficiency,  eta = 50*(Vmax-Vmin / Vmax+Vmin) =43.75 %

Page No. 415 Example 12.4.

In [7]:
from math import pi
VCE=2.
VCC=15.
eta=(pi/4.)*(1-(VCE/VCC))*100.
print "Collector circuity efficiency,"
print "    eta = (pi/4)*(1-(VCE/VCC))*100 =%0.2f %%"%eta

Collector circuity efficiency,
    eta = (pi/4)*(1-(VCE/VCC))*100 =68.07 %

Page No. 416 Example 12.5.

In [8]:
theta=8.
TA=27.
PD=3.
TJ=TA+(theta*PD)
print "We know that,  TJ = TA + theta*PD"
print "Therefore,  TJ = 27 degree C + (8 degree C/W)*3W =%0.2f degree C"%TJ

We know that,  TJ = TA + theta*PD
Therefore,  TJ = 27 degree C + (8 degree C/W)*3W =51.00 degree C

Page No. 417 Example 12.6.

In [9]:
TJ=160.
TA=40.
theta=80.
PD=(TJ-TA)/theta
print "PD = (TJ-TA)/thetaJ-A = (160-40)/80 =%0.2f W"%PD

PD = (TJ-TA)/thetaJ-A = (160-40)/80 =1.50 W

Page No. 418 Example 12.7.

In [10]:
thetaH=8.
TA=40.
TJ=160.
thetaJ=5.
thetaC=85.
x1=(thetaC*thetaH)/(thetaC+thetaH)
theta=thetaJ+x1
print "    theta_J-A = theta_J-C + theta_C-A || theta_HS-A =%0.2f degree C/w"%theta
PD=(TJ-TA)/theta
print "    PD = TJ-TA / theta_J-A =%0.2f W"%PD

    theta_J-A = theta_J-C + theta_C-A || theta_HS-A =12.31 degree C/w
    PD = TJ-TA / theta_J-A =9.75 W