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# Understanding Inductors - Basic Theory Explored

Updated on February 6, 2014

## Introduction

Anybody connected or related with the field of electricity or electronics would know what an inductor is or means. Basically any wire or conductor wound over a non-conductive base could be referred to as an inductor because such a device would immediately start exhibiting the property of inductance when used in a relevant electrical or electronic circuit.

## What is Inductance

The characteristic property of storing and releasing electrical energy exhibited by a coil of wire or a inductor is called inductance.

It's a property wherein the inductor exhibits the feature of storing electrical energy within it for a particular path of current (polarity) and consequently releasing this stored energy into associated circuitry in case the power is switched off or if the polarity of the current is reversed.

To be more precise, inductors will resist an AC or a alternating current and allow to pass DC or direct current through it. When a DC is applied to a circuit consisting of an inductor in its path, the current will be restricted for a moment during power switch ON and the next instant it will act like a short for the current and allow it to pass.

The time delay taken from the initial resistance and then acting as a short by the inductor will depend on the inductance value and for the period until which the inductor stores the specified amount of energy inside it.

Inductors with larger inductance value or more number of coils (turns) will exhibit slower turn ON and turn OFF and vice versa.

It could be considered the complementary of capacitors which does exactly the opposite. Capacitors basically resist DC and allow AC through, the time delay for achieving this likewise depends on how long the capacitor takes to store the electrical enrgy which in turn depends on its value or the capacitance.

## Using Inductor as Surge Suppressor in DC Circuits

As can be witnessed from the above discussion, a inductor is an extremely versatile and interesting electrical component that can be used for many vital application in the field of electrical and electronics.

An inductor when used in DC circuits will act just like a short and wil zero resistance to te path of the current. This would make you think, then how does an inductor help or become useful in DC circuitsk

Although normally an inductors will act like a short in DC circuits, it will provide a initial high resistance during power switch ONs.

This feature becomes an outstandingly important feature with inductors when used in DC circuits especially in those configurations where a power switch ON surge suppressing is too crucial.

Therefore we can use an inductor as an effective surge suppressor in DC circuits if at all the requirement calls for this feature.

## Using Inductor in AC Circuits

Inductors in AC circuits will behave like resistances and will try to oppose the current depending upon the reluctance or the inductance value of the device.

Higher inductance will generate higher resistance and thus inductors can be dimensioned appropriately in AC circuits for ensuring surge suppression as well as for safeguarding the critical components in the circuits.

## Inductors in Buck Boost Circuits

The unique feature of inductors of storing electrical energy and then releasing it back could be seen exploited in all buck boost converter circuits.

A buck converter is a device where an inductor is used to drop the voltage to a calculated lower level than the input source, while in boost circuits it's just the opposite, here the inductor is employed for generating higher voltages than the source voltage

When used in buck converter circuits, an inductor is pulsated with DC using relatively short pulses (PWMs) which in turn produces shorter back EMFs from the inductor. This short back EMF causes an equivalent lower amount of average voltage at the output. This results in a reduced votage generation across the inductor than the input source.

In the boost mode, the inductor is pulsated with much longer pulses (PWMs) thereby forcing the inductor to generate bigger potentials across itself. This relatively potential when filtered with a capacitor enables achieving higher or boosted voltages than the input supply source.

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