Inductance

Inductance
Inductance
Common symbols	L
SI unit	henry (H)
In SI base units	kg⋅m2⋅s−2⋅A−2
Derivations from; other quantities	L = V / ( I / t ); L = Φ / I;
Dimension	M1·L2·T−2·I−2

Inductance is the tendency of an electrical conductor to oppose a change in the electric current flowing through it. The electric current produces a magnetic field around the conductor. The magnetic field strength depends on the magnitude of the electric current, and follows any changes in the magnitude of the current. From Faraday's law of induction, any change in magnetic field through a circuit induces an electromotive force (EMF) (voltage) in the conductors, a process known as electromagnetic induction. This induced voltage created by the changing current has the effect of opposing the change in current. This is stated by Lenz's law, and the voltage is called back EMF.

Inductance is defined as the ratio of the induced voltage to the rate of change of current causing it.^[1] It is a proportionality constant that depends on the geometry of circuit conductors (e.g., cross-section area and length) and the magnetic permeability of the conductor and nearby materials.^[1] An electronic component designed to add inductance to a circuit is called an inductor. It typically consists of a coil or helix of wire.

The term inductance was coined by Oliver Heaviside in May 1884, as a convenient way to refer to "coefficient of self-induction".^[2]^[3] It is customary to use the symbol $L$ for inductance, in honour of the physicist Heinrich Lenz.^[4]^[5] In the SI system, the unit of inductance is the henry (H), which is the amount of inductance that causes a voltage of one volt, when the current is changing at a rate of one ampere per second.^[6] The unit is named for Joseph Henry, who discovered inductance independently of Faraday.^[7]

^ ^a ^b Serway, A. Raymond; Jewett, John W.; Wilson, Jane; Wilson, Anna; Rowlands, Wayne (2017). "Inductance". Physics for global scientists and engineers (2 ed.). Cengage AU. p. 901. ISBN 9780170355520.
^ Baker, Edward Cecil (1976). Sir William Preece, F.R.S.: Victorian Engineer Extraordinary. Hutchinson. p. 204. ISBN 9780091266103..
^ Heaviside, Oliver (1894). "The induction of currents in cores". Electrical Papers, Vol. 1. London: Macmillan. p. 354.
^ Elert, Glenn. "The Physics Hypertextbook: Inductance". Retrieved 30 July 2016.
^ Davidson, Michael W. (1995–2008). "Molecular Expressions: Electricity and Magnetism Introduction: Inductance".
^ Le Système international d’unités [The International System of Units] (PDF) (in French and English) (9th ed.), International Bureau of Weights and Measures, 2019, ISBN 978-92-822-2272-0, p. 160
^ "A Brief History of Electromagnetism" (PDF).

[Serway2017-1] Serway, A. Raymond; Jewett, John W.; Wilson, Jane; Wilson, Anna; Rowlands, Wayne (2017). "Inductance". Physics for global scientists and engineers (2 ed.). Cengage AU. p. 901. ISBN 9780170355520.

[2] Baker, Edward Cecil (1976). Sir William Preece, F.R.S.: Victorian Engineer Extraordinary. Hutchinson. p. 204. ISBN 9780091266103..

[3] Heaviside, Oliver (1894). "The induction of currents in cores". Electrical Papers, Vol. 1. London: Macmillan. p. 354.

[4] Elert, Glenn. "The Physics Hypertextbook: Inductance". Retrieved 30 July 2016.

[5] Davidson, Michael W. (1995–2008). "Molecular Expressions: Electricity and Magnetism Introduction: Inductance".

[6] Le Système international d’unités [The International System of Units] (PDF) (in French and English) (9th ed.), International Bureau of Weights and Measures, 2019, ISBN 978-92-822-2272-0, p. 160

[7] "A Brief History of Electromagnetism" (PDF).

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