Chapter 20 : Inductive Reactance

Example No. 20_1 Page No. 625

In [1]:
from math import pi
# How much is Xl of a 6-mH L at 41.67 kHz?

# Given data

f = 41.67*10**3#     # Frequency=41.67 kHz
L = 6.*10**-3#        # Inductor=6 mH

Xl = 20*pi*f*L#
print 'The Inductive Reactance = %0.2f Ohms'%Xl

The Inductive Reactance = 15709.22 Ohms

Example No. 20_2 Page No. 627

In [3]:
from math import pi
# Calculate the Xl of (a) a 10-H L at 60 Hz and (b) a 5-H L at 60 Hz.

# Given  data

f = 60.#     # Frequency=60 Hz
L1 = 10.#    # Inductor 1=10 H
L2 = 5.#     # Inductor 2=5 H
pi = 3.14

Xl1 = 20*pi*f*L1#
print 'The Inductive Reactance = %0.f Ohms'%Xl1

Xl2 = 2*pi*f*L2#
print 'The Inductive Reactance = %0.f Ohms'%Xl2

The Inductive Reactance = 37680 Ohms
The Inductive Reactance = 1884 Ohms

Example No. 20_3 Page No. 629

In [5]:
from math import pi
# Calculate the Xl of a 250-uH coil at (a) 1 MHz and (b) 10 MHz.

# Given data

f1 = 1.*10**6#    # Frequency1=1 MHz
f2 = 10.0*10**6#   # Frequency2=10 MHz
L = 250.0*10**-6#  # Inductor=250 uH
pi = 3.14#

# For 1 Mhz

Xl1 = 2*pi*f1*L#
print 'The Inductive Reactance = %0.f Ohms'%Xl1

# For 10 Mhz

Xl2 = 2*pi*f2*L#
print 'The Inductive Reactance = %0.f Ohms'%Xl2

The Inductive Reactance = 1570 Ohms
The Inductive Reactance = 15700 Ohms

Example No. 20_4 Page No. 631

In [7]:
# A coil with negligible resistance has 62.8 V across it with 0.01 A of current. How much is Xl?

# Given data

Vl = 62.8#      # Voltage across coil=62.8 Volts
Il = 0.01#      # Current in coil=0.01 Amps

Xl = Vl/Il#
print 'The Inductive Reactance = %0.f Ohms'%Xl

The Inductive Reactance = 6280 Ohms

Example No. 20_5 Page No. 632

In [10]:
from math import pi
# Calculate L of the coil when the frequency is 1000 Hz.

# Given data

Xl = 6280.#      # Inductive reactance=6280 Ohms
f = 1000.#       # Frequency=1000 Hz
pi = 3.14#

L = Xl/(2.*pi*f)#
print'The value of Inductor = %0.2f Henry'% L

The value of Inductor = 1.00 Henry

Example No. 20_6 Page No. 633

In [12]:
from math import pi
# Calculate L of a coil that has 15,700 Ohms of Xl at 12 MHz.

# Given data

Xl = 15700.#    # Inductive reactance=15700 Ohms
f = 12.0*10**6#   # Frequency=12 MHz
pi = 3.14#

L = Xl/(2*pi*f)#
print'The value of Inductor = %0.2e Henry'% L
print 'i.e Approx 208.8*10**-6 OR 208.8 uH'

The value of Inductor = 2.08e-04 Henry
i.e Approx 208.8*10**-6 OR 208.8 uH

Example No. 20_7 Page No. 634

In [13]:
from math import pi
# At what frequency will an inductance of 1 H have a reactance of 1000 ?

# Given data

Xl = 1000.#    # Inductive reactance=1000 Ohms
L = 1.#        # Inductor=1 H

f = Xl/(2.*pi*L)#
print 'The Frequency = %0.2f Hertz'%f

The Frequency = 159.15 Hertz