Inductance

Equivalent diagram and vector diagram

Inductance is the creation of an electric field due to a change in magnetic flux density. This change in flux density generates a force that acts on the conductor. This principle applies to motors and - if a force results in a movement in the electric field - to generators.

A change in the electric current alters the magnetic field and the inductance induces a counter electromotive force that acts against the current flow. A pure inductance results in a phase shift where the current lags the voltage by 90°. Ohmic resistances or capacitances in real circuits produce a variable phase shift angle $\varphi $.

In an AC circuit, an inductance produces an inductive reactance which, ignoring the phase shift angle, is the product of the angular frequency ? and the inductance. Taking the phase angle into consideration gives the complex impedance$j\omega L$.