Equivalent circuits from electromagnetic theory low-frequency induction devices

A method is described for rearranging the electromagnetic-field-theory solutions of certain low-frequency devices into equivalent-circuit form. Two types of equivalent circuit are described, one 'basic' the other 'terminal'. An equivalent circuit can aid the understanding of a device, and it also makes possible substantial saving in computer time. To illustrate the method, the equivalent circuit of one type of cylindrical induction device is derived. Finally, a list is given of other devices for which equivalent circuits have been developed.