Capacitors, Magnetic Circuits, and Transformers is a free introductory textbook on the physics of capacitors, coils, and transformers. See the editorial for more information....

Inductive Circuits

An inductive circuit may be defined as an electric circuit in which a current produces appreciable magnetic flux linkage. Windings in electromagnetic devices are inductive, as for example those in choke coils, relays, loud speakers, transformers, motors, generators, transmission lines, and antennas. It is important to note that inductance is associated with magnetic circuits, although such circuits do not necessarily have cores of magnetic materials since the path of the magnetic flux may be confined to air and to the current-carrying portions of the circuit. Such is the case with air-core chokes and air-core transformers having windings of nonmagnetic material, and with transmission lines having nonmagnetic conductors. Generally speaking, there are two kinds of inductance, namely, self-inductance and mutual inductance. The self-inductance of an electric circuit is the parameter that is associated with the flux linkage resulting from the current flowing in the circuit itself. Mutual inductance is the parameter associated with flux linkage with one electric circuit produced by the current flowing in another electric circuit. In other words, mutual inductance exists between two or more electric circuits when they have magnetic flux linkage in common.

Last Update: 2011-02-16