Chapter-7 : Oscillators (Sinusoidal As Well As Non-Sinusoidal)

Example : 7.1 - Page No 232

In [2]:
import math
from numpy import pi
from math import sqrt
# Given data
f=200 # in Hz
# Let us take
C=0.1 # in micro F
C=C*10**-6 # in F
R=1/(2*pi*f*C*sqrt(6)) # in ohm
R=R*10**-3 # in k ohm
# R1>=10*R, Let
R1=10*R # in kohm
R_f= 29*R1 # in k ohm
R_f=R_f*10**-3  # in M ohm
R_f=math.ceil(R_f) 
print "Resistor of phase-shift oscillator = %0.f Mohm" %R_f

Resistor of phase-shift oscillator = 1 Mohm

Example : 7.2 - Page No 232

In [3]:
# Given data
f=1 # in kHz
f=f*10**3 # in Hz
V_CC= 10 # in volt
I_B_max= 500 # in nA (for 741 IC op-amp)
I_B_max= I_B_max*10**-9 # in A
I1= 100*I_B_max # in A
V_out= (V_CC-1) # in volt
V_in= V_out/29 
R1= V_in/I1 # in ohm
R1=R1*10**-3 #in k ohm
# 5.6 k ohm resistor may be used for R1, being standard value resistor
R1=5.6 # in k ohm (standard value)
A=29 
R_f= A*R1 
# 180 k ohm resistor may be used to provide A > 29
R_f=180 # in k ohm (standard value)
R_comp= R_f 
R=R1 # in k ohm
R=R*10**3 # in ohm
C=1/(2*pi*f*R*sqrt(6)) # in F
C=C*10**6 # in micro F
print "Value of R_comp = R_f = %0.f kohm" %R_comp
print "Value of R = R1 = %0.1f in kohm" %(R*10**-3)
print "Value of capacitor = %0.2f micro F" %C

Value of R_comp = R_f = 180 kohm
Value of R = R1 = 5.6 in kohm
Value of capacitor = 0.01 micro F

Example : 7.3 - Page No 235

In [12]:
# Given data
f=10 # in kHz
f=f*10**3 # in Hz
I_Bmax= 500 # in nA
I_Bmax= I_Bmax*10**-9 # in amphere
# Let current through resistor R1 be equal to 100 times I_Bmax, so
I_1= 100*I_Bmax # in amp
Vcc= 10 # in volt
Vout= Vcc-1 # in volt
Addition_RfR1= Vout/(500*10**-6) # value of Rf+R1 in ohm
Addition_RfR1=Addition_RfR1*10**-3 # in kohm
# Rf= 2*R1, So
R1= Addition_RfR1/3 # (used 5.6 kohm Standard value resistor)
print "Value of R1 = %0.f kohm (Standard value 5.6 k ohm)" %R1
R1= 5.6 # in kohm     (used 5.6 kohm Standard value resistor)
Rf= 2*R1 # in kohm# (used 12 kohm standard value resistor)
print "Value of Rf = %0.1f kohm (Standard value 12 k ohm)" %Rf
Rf= 12 # k ohm (used 12 kohm standard value resistor)
R=R1 # in kohm
C= 1/(2*pi*f*R) # in F (Used 2700pF standard value)
C=2700 # in pF 
print "Value of R  = %0.1f kohm" %R
print "Value of C  = %0.f pF" %C

Value of R1 = 6 kohm (Standard value 5.6 k ohm)
Value of Rf = 11.2 kohm (Standard value 12 k ohm)
Value of R  = 5.6 kohm
Value of C  = 2700 pF

Example : 7.4 - Page No 235

In [13]:
# Given data
R= 1 # in kohm
R=R*10**3 # in ohm
C= 4.7 # in micro F
C=C*10**-6 # in F
omega=1/(R*C) # in radians/second
f=omega/(2*pi) # in Hz
print "Frequency of the oscillation of the circuit = %0.2f Hz" %f

Frequency of the oscillation of the circuit = 33.86 Hz

Example : 7.6 - Page No 236

In [15]:
# Given data
R= 10 # in kohm
R=R*10**3 # in ohm
C= 100 # in pF
C=C*10**-12 # in F
f=1/(2*pi*R*C) # in Hz
print "Frequency of the oscillation of the circuit = %0.2f kHz" %(f*10**-3)

Frequency of the oscillation of the circuit = 159.15 kHz

Example : 7.7 - Page No 238

In [16]:
# Given data
fo= 318 # in Hz
C= 0.015 # in microF
C=C*10**-6 # in F
R=0.159/(fo*C) # in ohm
R=R*10**-3 # in kohm
R=int(R) 
print "Value of C1 = C2 = C3 = %0.3f micro F" %(C*10**6)
print "Value of R1 = R2 = R3 = %0.f in kohm" %R

Value of C1 = C2 = C3 = 0.015 micro F
Value of R1 = R2 = R3 = 33 in kohm

Example : 7.8 - Page No 238

In [17]:
# Given data
fo= 1.5 # in kHz
fo=fo*10**3 # in Hz
C= 0.01 # in microF
C=C*10**-6 # in F
R=0.159/(fo*C) # in ohm
R=R*10**-3 # in kohm
R=int(R) 
print "Value of C1 = C2 = C3 = %0.2f micro F" %(C*10**6)
print "Value of R1 = R2 = R3 = %0.f in kohm" %R

Value of C1 = C2 = C3 = 0.01 micro F
Value of R1 = R2 = R3 = 10 in kohm

Example : 7.9 - Page No 245

In [18]:
# Given data
C= 0.1 # in microF
C=C*10**-6 # in F
R=12 # in kohm
R=R*10**3 # in ohm
R1=120 # in kohm
R1=R1*10**3 # in ohm
Rf=1 # in Mohm
Rf=Rf*10**6 # in ohm
V_sat= 10 # in volt
# Part(i)
f=Rf/(4*R1*R*C) #in Hz
print "(i)   : Signal Frequency = %0.3f kHz" %(f*10**-3)

# Part(ii)
Vp_p= float(2*R1*V_sat)/Rf # in Vp_p

print "(ii)  : Amplitude of the triangular wave = %0.1f Vp_p" %Vp_p

# Part(iii)
Vp_p= (V_sat)-(-V_sat) 
print "(iii) : Amplitude of the square wave = %0.f Vp_p" %Vp_p

(i)   : Signal Frequency = 1.736 kHz
(ii)  : Amplitude of the triangular wave = 2.4 Vp_p
(iii) : Amplitude of the square wave = 20 Vp_p

Example : 7.11 - Page No 246

In [32]:
# Given data
C1= 0.01 # in microF
C1=C1*10**-6 # in F
R1=120 # in kohm
R1=R1*10**3 # in ohm
R2=1.2 # in kohm
R2=R2*10**3 # in ohm
R3=6.8 # in kohm
R3=R3*10**3 # in ohm
V_sat= 15 # in volt
# Part(a)
Vp_p= 2*(R2/R3)*V_sat #in volt
print "(a) : Peak to peak amplitude of triangular wave = %0.3f volt" %Vp_p

# Part(b)
fo= R3/(4*R1*C1*R2) #in Hz
print "(b) : Frequency of triangular wave = %0.2f kHz" %(fo*10**-3)

(a) : Peak to peak amplitude of triangular wave = 5.294 volt
(b) : Frequency of triangular wave = 1.18 kHz

Example : 7.12 - Page No 249

In [21]:
from math import log
# Given data
T= 100 # in micro sec
T=T*10**-6 #in se
V_sat= 12 # in volt
V1= 0.7 # in volt
V= 0.7 # in volt
V_D1= V 
V_D2=V_D1 
C1= 0.1 # in microF
C1=C1*10**-6 # in F
Bita1= 0.1 
# Formula T= R3*C1*log((1+V1/V_sat)/(1-Bita1))
R3= T/(C1*log((1+V1/V_sat)/(1-Bita1))) # in ohm
print "Value of R3 = %0.3f kohm (Standard value 6.8 kohm)" %(R3*10**-3)

Value of R3 = 6.171 kohm (Standard value 6.8 kohm)