a-c

noun

1. 1

   An electric current in which the direction of flow of the electrons reverses periodically, such as sawtooth, sinusoidal or square wave current.

2. 2

   An electric current in which the direction of flow of the electrons reverses periodically by a sinusoidal law, hence 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.