an electric current that reverses its direction periodically: abbrev. AC
An electric current that reverses direction in a circuit at regular intervals.
(plural alternating currents) (abbreviated as AC)
- an electric current in which the direction of flow of the electrons reverses periodically having an average of zero, with positive and negative values (with a frequency of 50 Hz in Europe, 60 Hz in the US, 400 Hz for airport lighting, and some others); especially such a current produced by a rotating generator or alternator.