Inductors & Inductance Basics

- basic information about inductors and inductance including mutual inductance and self-inductance.

In electromagnetism and electronics, inductance is the ability of an inductor to store energy in a magnetic field.

Inductors generate an opposing voltage proportional to the rate of change in current in a circuit.

This property also is called self-inductance to discriminate it from mutual inductance, describing the voltage induced in one electrical circuit by the rate of change of the electric current in another circuit.

Inductance is one of the basic circuit parameters used in circuit design and development.

Inductors appear in a variety of formats, as chokes, transformers, inductors and many other items.

Inductance basics

Inductance is caused by the magnetic field generated by electric currents flowing within an electrical circuit. Typically coils of wire are used as a coil increases the coupling of the magnetic field and increases the effect.

There are two ways in which inductance is used:

  • Self-inductance:   Self-inductance is the property of a circuit, often a coil, whereby a change in current causes a change in voltage in that circuit due to the magnetic effect of caused by the current flow.. It can be seen that self-inductance applies to a single circuit - in other words it is an inductance, typically within a single coil. This effect is used in single coils or chokes.
  • Mutual-inductance:   Mutual inductance is an inductive effect where a change in current in one circuit causes a change in voltage across a second circuit as a result of a magnetic field that links both circuits. This effect is used in transformers.

Inductance circuit symbols

The circuit symbol for an inductor indicates the coil nature of the inductor. There are several formats indicating whether the inductor or transformer has a air core or a magnetic core.

Inductor circuit symbols
Selection of inductor circuit symbols

While the basic inductor is widely used in many circuits, the transformer is also used in very many applications.

Transformer circuit symbols
Selection of transformer circuit symbols

Inductance units

When indicating an inductor on a circuit diagram or within an equation, generally the symbol "L" is used. On circuit diagrams, inductors are generally numbered, L1, L2, etc.

The SI unit of inductance is the henry, H. The inductance of a circuit is one henry if the rate of change of current in a circuit is one ampere per second and this results in an electromotive force of one volt.

One henry is equal to 1 Wb/A.

. . . .   |   Next >

Share this page

Want more like this? Register for our newsletter

Autonomous Cars – End of the Year or Not Yet Near? Mark Patrick | Mouser Electronics
Autonomous Cars – End of the Year or Not Yet Near?
Tesla CEO Elon Musk has predicted that his company’s cars might be able to drive across the US autonomously as early as the beginning of 2018. Is this ambitious goal possible?
LTE Advanced Pro and Road to 5G
Chapter 1 of the new book by Dahlman et al on the latest cellular developments and current 5G status. Get this free download.

More whitepapers
 is operated and owned by Adrio Communications Ltd and edited by Ian Poole. All information is © Adrio Communications Ltd and may not be copied except for individual personal use. This includes copying material in whatever form into website pages. While every effort is made to ensure the accuracy of the information on, no liability is accepted for any consequences of using it. This site uses cookies. By using this site, these terms including the use of cookies are accepted. More explanation can be found in our Privacy Policy