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What is Inductance?

Alexis W.
Alexis W.

The term inductance generally refers to an electrical circuit. It represents the measure within the circuit between the charges. It can also measure the amount of input signal that has been provided to the circuit, and the amount of change in that input signal as it is passed through the circuit. This term can also refer to the rate of change that occurs within the circuit that remains in the circuit’s components, as compared to the amount of signal that is applied to the circuit’s input.

Another term for this measurement within a circuit is self-inductance. This term is used to differentiate a circuit’s inductance within itself from the amount of change in a circuit that occurs due to the input signal in another circuit becoming varied. This instance is most commonly referred to as mutual inductance.


When an electric current created as an input signal is applied to a circuit containing electrical components, there is a magnetic field also created. This field is created due to the use of inductors. Inductors are coiled wire units used to collect and concentrate the amount of charge through the created magnetic field and pass it on through the circuit as voltage. The amount of voltage created from the charge provided to the circuit and the change that occurs in the voltage as it passes through the circuit and magnetic field is the measurable amount of the circuit’s inductance.

When mutual inductance occurs, this means there are two circuits located within an amount of space of each other such that they produce magnetic fields that interact with each other. This interaction alters the voltage within the opposite circuit. Another way that mutual inductance is created is when the two circuits are run in sequence of each other, so that when one circuit’s generated magnetic field creates a change within the circuit, it also affects the amount of signal that is applied to the following circuit.

This measurable amount of change within the second circuit that has been caused by the inductance in the first circuit represents the mutual inductance properties of the circuits. The requisite factor in the creation of mutual inductance, however, is that each circuit is strong enough in terms of voltage to create a magnetic field within its components that is capable of altering the field created by the opposing circuit. Otherwise, this phenomenon will not occur.

Discussion Comments


@NathanG - I’m not an expert, but I do work in the utilities industry. We have things called transformers which are used to step up and step down electrical currents.

They use inductive reactance to do this. As the article correctly states, when you have two or more of these types of circuits close together, you wind up with fluctuations in the voltage.

Transformers exploit this tendency by using those fluctuations to increase or decrease the voltage as needed. Of course, you can buy smaller transformers from an electronics store and experiment with the technique on a scaled down level.

You have probably used transformers if you’ve traveled overseas and needed to step down their voltage so that it would work correctly with your appliances that use only 110 volts, alternating current.


Electromagnetic induction is fairly easy to demonstrate. Just wrap some wires around a coil, and pass a magnet through it. If you want to measure the amount of current, you can hook up an inductance meter.

It will probably be minimal current, depending on the size of the magnet and the amount of wiring that you have. I used to do this stuff way back when I was in high school, just as simple science experiments.

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