Electric current that reverses direction, usually many times per second. Most electrical generators produce alternating current.

A measure of how much electricity is moving through a conductor.

A total power failure over a large area; usually caused by the failure of major generating equipment or transmission facilities.

Slag or other residue remaining in the boiler after coal is burned.

A small, temporary voltage reduction implemented by a utility to conserve electric power during periods of high use.

Amount of heat needed to raise the temperature of 1 pound of water by 1 degree Fahrenheit.

An electrical conductor that serves as a common connection for two or more electrical circuits.

A device that stores electrical charges and can be used to maintain voltage levels in power lines and improve electrical-system efficiency.

Path that electricity follows.

A switch that opens an electric circuit when a short occurs.