Chapter 12 : Oscillators

Example 12.1: Page No 664

In [2]:
from __future__ import division
from math import pi, sqrt
#               (a) RD
#               (b) Product RC
#               (c) Reasonable value of R and C

fo=8e3# # in hertz
mu=59#
rd=10# # in kilo-ohms

print "Part (a)"
RD=29*rd/(mu-29)# # in kilo-ohms
print "RD = %0.2f kΩ​ "%RD

print "Part (b)"
RC=1/(2*pi*fo*sqrt(6))# # in seconds
RC=RC*1e6# # in micro-seconds
print "Product RC = %0.2f µs "%RC

print "Part (c)"
R=50# # in kilo-ohms
C=RC/R# # in nano-farad
C=C*1e3# # in pico-farad
print "Reasonable value of R = %0.2f kΩ​ "%R
print "Reasonable value of C = %0.2f pF "%C
Part (a)
RD = 9.67 kΩ​ 
Part (b)
Product RC = 8.12 µs 
Part (c)
Reasonable value of R = 50.00 kΩ​ 
Reasonable value of C = 162.44 pF 

Example 12.2: Page No 665

In [1]:
from __future__ import division
from math import pi, sqrt
#Designing a Wein Bridge Oscillator

fo=2e3# # in hertz
R=10# # in kilo-ohms
C=1/(2*pi*fo*R*1e3)# # in farads
C=C*1e9# # in nano-farads
print "R1 = %0.2f kΩ​ "%R
print "R2 = %0.2f kΩ​ "%R
print "R3 = %0.2f kΩ​ "%(2*R)
print "R4 = %0.2f kΩ​ "%R
print "C1 = %0.2f nF "%C
print "C2 = %0.2f nF "%C
R1 = 10.00 kΩ​ 
R2 = 10.00 kΩ​ 
R3 = 20.00 kΩ​ 
R4 = 10.00 kΩ​ 
C1 = 7.96 nF 
C2 = 7.96 nF 

Example 12.3: Page No 669

In [2]:
from __future__ import division
from math import pi, sqrt
#Range of capacitance

L1=2e-3# # in henry
L2=1.5e-3# # in henry
fmin=1000e3# # in hertz
fmax=2000e3# # in hertz
Cmin=1/((2*pi*fmax)**2*(L1+L2))# # in farads
Cmax=1/((2*pi*fmin)**2*(L1+L2))# # in farads
Cmin=Cmin*1e12# # in pico-farads
Cmax=Cmax*1e12# # in pico-farads
print "Minimum value of C = %0.2f pF "%Cmin
print "Maximum value of C = %0.2f pF "%Cmax
Minimum value of C = 1.81 pF 
Maximum value of C = 7.24 pF