Chapter 6 - Dielectric Properties of Materials

Exa 6.1 page 291

In [1]:
from math import pi
# given data
epsilon_r=2.5 
epsilon_o=8.854*10**-12 
d=.2*10**-3 # in m
A=20*10**-4 # in m**2
omega=2*pi*10**6 # in radians/s
f=10**6 
tan_delta=4*10**-4 
C=epsilon_o*epsilon_r*A/d # in F
print "Capicitance is : ",(C*10**12)," miu miu F" 
# Formula P=V**2/R, so
# R=V**2/P and P= V**2*2*pi* f * C * tan delta, putting the value of P, we get
R=1/(2*pi*f*C*tan_delta) # in ohm
print "The element of parallel R-C circuit is : %0.3f"%(R*10**-6)," M ohm" 

Capicitance is :  221.35  miu miu F
The element of parallel R-C circuit is : 1.798  M ohm

Exa 6.2 page 301

In [2]:
# given data
g=0.055 # in V-m/N
t=2*10**-3 # in m
P=1.25*10**6 # in N/m**2
epsilon=40.6*10**-12 # in F/m
V_out=g*t*P 
print "Output voltage is : ",(V_out)," V" 
# Formula Charge Sensivity=epsilon_o*epsilon_r*g=epsilon*g
ChargeSensivity=epsilon*g 
print "Charge Sensivity is : ",(ChargeSensivity)," C/N" 

Output voltage is :  137.5  V
Charge Sensivity is :  2.233e-12  C/N

Exa 6.3 page 301

In [3]:
# given data
V_out=150 # in V
t=2*10**-3 # in m
g=0.05 # in V-m/N
A=5*5*10**-6 # in m**2
F=V_out*A/(g*t) # in N
print "Force applied is : ",F," N"

Force applied is :  37.5  N

Exa 6.4 page 302

In [4]:
# given data
g=12*10**-3 # in V-m/N
t=1.25*10**-3 # in m
A=5*5*10**-6 # in m**2
F=3 # in N
ChargeSensitivity=150*10**-12 # in C/N
P=F/A 
V_out=g*t*P # in V
Q=ChargeSensitivity*F 
print "Total charge developed is : "+str(Q)+" C" 
# Formula C=Q/V 
C=Q/V_out 
print "Capacitance is : ",(C*10**12)," micro F" 

# Note: Answer in the Book is wrong

Total charge developed is : 4.5e-10 C
Capacitance is :  250.0  micro F