Question

A 750-turn coil of inductance 3 H carries a current of 2 A. Calculate the flux linking the

coil and the e.m.f. induced in the coil when the current collapses to zero in 20 ms​

Answer 1

ur answer is here hope it helps u hope it is clear pls mark me as a brainliest

Register to download premium content!

X

DeutschDeutsch PolskiPolski

Register

Log In

AC Circuits

Amplifiers

Attenuators

Binary Numbers

Boolean Algebra

Capacitors

Combinational Logic

Connectivity

Counters

DC Circuits

Diodes

Electromagnetism

Filters

Inductors

Input/Output Devices

Logic Gates

Miscellaneous Circuits

Operational Amplifiers

Oscillator

Power Electronics

Power Supplies

Premium

RC Networks

Resistors

Resources

Sequential Logic

Systems

Transformers

Transistors

Waveform Generators

Premium Content

Further Education

Sitemap

Contact Us

Home / Inductors / Inductance of a Coil

Inductance of a Coil

Inductance is the name given to the property of a component that opposes the change of current flowing through it and even a straight piece of wire will have some inductance

Inductors do this by generating a self-induced emf within itself as a result of their changing magnetic field. In an electrical circuit, when the emf is induced in the same circuit in which the current is changing this effect is called Self-induction, ( L ) but it is sometimes commonly called back-emf as its polarity is in the opposite direction to the applied voltage.

When the emf is induced into an adjacent component situated within the same magnetic field, the emf is said to be induced by Mutual-induction, ( M ) and mutual induction is the basic operating principal of transformers, motors, relays etc. Self inductance is a special case of mutual inductance, and because it is produced within a single isolated circuit we generally call self-inductance simply, Inductance.

The basic unit of measurement for inductance is called the Henry, ( H ) after Joseph Henry, but it also has the units of Webers per Ampere ( 1 H = 1 Wb/A ).

Lenz’s Law tells us that an induced emf generates a current in a direction which opposes the change in flux which caused the emf in the first place, the principal of action and reaction. Then we can accurately define Inductance as being: “a coil will have an inductance value of one Henry when an emf of one volt is induced in the coil were the current flowing through the said coil changes at a rate of one ampere/second”.

In other words, a coil has an inductance, ( L ) of one Henry, ( 1H ) when the current flowing through the coil changes at a rate of one ampere/second, ( A/s ). This change induces a voltage of one volt, ( VL ) in it. Thus the mathematical representation of the rate of change of current through a wound coil per unit time is given as:

current through a coil

Where: di is the change in the current in Amperes and dt is the time taken for this current to change in seconds. Then the voltage induced in a coil, ( VL ) with an inductance of L Henries as a result of this change in current is expressed as:

voltage induced in a coil

Note that the negative sign indicates that voltage induced opposes the change in current through the coil per unit time ( di/dt ).

From the above equation, the inductance of a coil can therefore be presented as:

Inductance of a Coil

inductance equation

Where: L is the inductance in Henries, VL is the voltage across the coil and di/dt is the rate of change of current in Amperes per second, A/s.

Inductance, L is actually a measure of an inductors “resistance” to the change of the current flowing through the circuit and the larger is its value in Henries, the lower will be the rate of current change.

We know from the previous tutorial about the Inductor, that inductors are devices that can store their energy in the form of a magnetic field. Inductors are made from individual loops of wire combined to produce a coil and if the number of loops within the coil are increased, then for the same amount of current flowing through the coil, the magnetic flux will also increase.

So by increasing the number of loops or turns within a coil, increases the coils inductance. Then the relationship between self-inductance, ( L ) and the number of turns, ( N ) and for a simple single layered coil can be given as: