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# Inductance

Inductance is introduced intentionally in circuits for various purposes, some of which are described in the sequel. In most applications where either inductance or capacitance could be used, such as in active filters and integrating and differentiating circuits, capacitance is preferred because of the smaller size and lower cost of capacitors, relative to inductors. Also, it is easier to confine the electric field in a capacitor than it is to confine the magnetic field produced by an inductor, so capacitors produce less electrical interference than inductors.

 Related Calculators Inductance Calculator Inductive Reactance Calculator

## Definition

Inductance the characteristics of an electrical conductor that opposes a change in current flow. The symbol for inductance is L. An inductor is a device that stores energy in a magnetic field. Inductance exhibits the same effect on current in an electric circuit as inertia does on velocity of a mechanical object. It takes more work to start a load moving than it does to keep it moving because the load possesses the property of inertia. Inertia is the characteristics of mass that opposes a change in velocity. Once current is moving though a conductor, inductance helps to keep it moving. The effects of inductance helps to keep it moving. The effects of inductance are sometimes desirable and other times undesirable.

All conductors have some inductance. The amount of inductance depends on the conductor and the shape of it. Straight wire has small amounts of inductance, whereas coils of wire have much more inductance.

## What is Mutual Inductance

The property of one coil due to which it opposes the change of current in the other coil is called mutual inductance between the two coils. This property is attained by a coil due to mutually induced emf in the coil, while current in the neighbouring coil is changing.

## Inductance Formula

An inductor is a device that can store energy in a magnetic field. Coils, solenoids and toroids are all examples of inductors. For practical inductors, however, nonideal effects may alter this voltage-current relationship through an additional series resistance and possible lead capacitance and inductance. Assuming an ideal inductor, the computation of inductance becomes a  strictly magnetostatic problem. Considering one or more loops of current in space, it can be shown that the magnetic flux through a loop is proportional to the current that produces the magnetic flux. The constant of proportionality is called inductance with units of henry (H). Specifically, inductance is defined in terms of the flux linkage and current as:
$L_{ij}$ = $\frac{Flux\ linkage\ through\ ith\ coil\ due\ to\ current\ in\ jth\ coil}{Current\ in\ jth\ coil}$