when a current flows through a conductor, a magnetic field builds up around the conductor. This field contains energy and is the

foundation for inductance.

## PRINCIPLES OF INDUCTANCE

Inductance is the characteristic of an electrical conductor that opposes a change in current flow. The symbol for inductance is L. An inductor is a device that stores energy in a magnetic field.

## INDUCTORS

Inductors are devices designed to have a specific inductance. They consist of a conductor coiled around a core and are classified by the type of core materialâ€”magnetic or nonmagnetic.

## L/R TIME CONSTANTS

An L/R time constant is the time required for current through a conductor to increase to 63.2% or decrease to 36.8% of the maximum current.