# Chapter 7 , Passive Circuit Elements¶

## Example 7.4 , Page Number 121¶

In [1]:
import math

#Variables

N = 150.0                       #Number of turns
mur = 3540.0                    #Relative permeability (in H/m)
mu0 = 4*math.pi * 10 **-7       #Absoulte permeability (in H/m)
l = 0.05                        #coil length (in meter)
A = 5 * 10**-4                  #Area of cross - section (in metersquare)

#Calculation

L = (mur * mu0 * A * N**2)/l    #Coil inductance (in Henry)

#Result

print "The coil inductance is ",round(L,2)," Henry."

The coil inductance is  1.0  Henry.


## Example 7.5 , Page Number 122¶

In [2]:
import math

#Variables

L1 = 40.0                      #Inductance (in micro-Henry)
L2 = 80.0                      #Inductance (in micro-Henry)
M = 11.3                       #Mutual Inductance (in micro-Henry)

#Calculation

k = M/(L1 * L2)**0.5           #Coefficient of Coupling

#Result

print "Coefficient of coupling is ",round(k,2),"."

Coefficient of coupling is  0.2 .


## Example 7.6 , Page Number 125¶

In [2]:
import math

#Variables

Q = 90.0                 #Q-factor
L = 15.0 * 10**-6        #Inductance (in Henry)
f = 10.0 * 10**6         #Frequency (in Hertz)

#Calculation

Ro = 2*math.pi*f*L/Q     #d.c. resistance (in ohm)

#Result

print "d.c. resistance of coil is ",round(Ro,1)," ohm."

d.c. resistance of coil is  10.5  ohm.


## Example 7.7 , Page Number 126¶

In [6]:
import math

#Variables

k = 5.0                   #dielectric constant
A = 0.04                  #Plate area (in meter-square)
d = 0.02                  #Thickness of dielectric(in meter)
eps0 = 8.85 * 10**-12     #Absolute permittivity (in kg*m**3*s**-3*A**-2)

#Calculation

C = eps0 * k * A / d      #Capacitance (in Farad)

#Result

print "Capacitance of parallel plate capacitor is ",C * 10**12,"pF."

Capacitance of parallel plate capacitor is  88.5 pF.


## Example 7.8 , Page Number 127¶

In [7]:
import math

#Variables

k = 1200.0                   #dielectric constant
A = 0.2                      #Plate area (in meter-square)
eps0 = 8.85 * 10**-12        #Absolute permittivity (in kg*m**3*s**-3*A**-2)
C = 0.428                    #Capacitance (in micro-farad)

#Calculation

d = eps0 * k * A / C         #thickness of dielectric (in meter)

#Result

print "Thickness of dielectric is ",round(d * 10**9,2)," mm."

Thickness of dielectric is  4.96  mm.