# Magnetic inductance

Magnetic inductance is not to be confused with "Magnetic induction", which usually refers to Magnetic field.

In a magnetic circuit, magnetic inductance (inductive magnetic reactance) is the analogy to inductance in an electrical circuit. Magnetic inductance is a concept in the gyrator-capacitor model for magnetic systems.In the SI system, it is measured in units of -Ω−1. This model makes magnetomotive force (mmf) the analog of electromotive force in electrical circuits, and time rate of change of magnetic flux the analog of electric current. The gyrator-capacitor model is a lumped-element model for analysis of magnetic fields.

For phasor analysis the magnetic inductive reactance is:

${\displaystyle x_{\mathrm {L} }=\omega L_{\mathrm {M} }}$

Where:

${\displaystyle L_{\mathrm {M} }}$ is the magnetic inductivity (SI Unit: -s·Ω−1)
${\displaystyle \omega }$ is the angular frequency of the magnetic circuit

In the complex form it is a positive imaginary number:

${\displaystyle jx_{\mathrm {L} }=j\omega L_{\mathrm {M} }}$

The magnetic potential energy sustained by magnetic inductivity varies with the frequency of oscillations in electric fields. The average power in a given period is equal to zero. Due to its dependence on frequency, magnetic inductance is mainly observable in magnetic circuits which operate at VHF and/or UHF frequencies.

The notion of magnetic inductivity is employed in analysis and computation of circuit behavior in the gyrator-capacitor model in a way analogous to inductance in electrical circuits.