Inductor: Definition, Function & Uses

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  • 0:04 Inductor
  • 1:04 How an Inductor Works
  • 2:32 Everyday Inductor Uses
  • 4:04 Lesson Summary
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Lesson Transcript
Instructor: Michael Blosser

Michael has a Masters in Physics and a Masters in International Development. He has over 5 years of teaching experience, teaching Physics, Math, and English classes.

This lesson will introduce the reader to the concept of an inductor, defining what an inductor is, how it works, and common uses of inductors in our everyday world.


Inductors are essential parts of electrical circuits and have been used in a variety of essential everyday applications. What is an inductor and what is induction? How do inductors work and why are they important? This lesson will introduce the science and physics behind an inductor and describe how they're used in everyday applications.

An inductor is a coil of wire around a central core that can consist of a variety of materials. Hence, inductors are also known as a coil or a reactor. If an electric current flows through this coil of wire it produces a magnetic field around it. The strength of the magnetic field induced by the electric current flowing around the central core depends on the type of material of the core, the number of coils of the wire, and the cross-sectional area and length of the coil. For example, if the central core was also magnetic, the magnetic field around the inductor will be a lot stronger. Inductors are a very important component in electronic circuits because they're able to resist or oppose changes of current in the circuit.

How an Inductor Works

An inductor works by inducing a magnetic field as an electric current flows through its coil of wire. This magnetic field temporarily stores electric energy as magnetic energy, creating a voltage across the inductor. The strength of the magnetic field or the inductance'of the inductor is dependent on a variety of properties such as the number of coils in the wire, the cross-sectional area of the inductor, and the type of material the inductor's core is made out of.

The inductance L of an inductor can be calculated with the following equation:

Eqn 1

This is where:

  • μ is the magnetic permeability of the inductor
  • k is the Nagaoka coefficient
  • N is the number of turns of the coil
  • S is the cross-sectional area of the coil
  • l is the length of the coil in the axial direction

The inductance (L) of an inductor is given in units of Henry, after the physicist Joseph Henry.

The different types of cores for inductors can greatly increase its inductance. For example, an inductor that has an iron core (whose magnetic permeability is 600) will have a lot larger inductance than an inductor that has a core of air (whose magnetic permeability is 1). These physical properties of an inductor allow it to store a voltage across the inductor and also resist sudden changes in the current. Therefore, an inductor is an electrical component that lets DC (Direct Current) flow through it but not AC (Alternating Current).

Everyday Inductor Uses

Since inductors have very special electrical, magnetic, and physical properties they can be found in numerous everyday applications such as filters, sensors, transformers, motors, and for energy storage.

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