an electric current that reverses direction at regular intervals, having a magnitude that varies continuously in sinusoidal manner.
a continuous electric current that periodically reverses direction, usually sinusoidally AC Compare direct current
An electric current that repeatedly changes its direction or strength, usually at a certain frequency or range of frequencies. The term is also used to describe alternating voltages. Power stations generate alternating current because it is easy to raise and lower the voltage of such current using transformers; thus the voltage can be raised very high for transmission (high voltages lose less power as heat than do low voltages), and lowered to safe levels for domestic and industrial use. In North America, the frequency of alternation of the direction of flow is 60 Hz, or 60 cycles per second. In other parts of the world it is 50 Hz. Compare direct current. See Notes at current, Tesla.
alternating current (AC)
An electric current in which the flow reverses periodically. (Compare direct current (DC).)
Note: In the United States, most household current is AC, going through sixty reversal cycles each second. Electric motors in household appliances are designed to work with current at this rate of reversal.
- Alternating group
the subgroup consisting of all even permutations, of the group of all permutations of a finite set.
- Alternating hemiplegia
alternating hemiplegia alternating hemiplegia n. Hemiplegia caused by a lesion on the opposite side of the brainstem, accompanied by an additional paralysis of a motor cranial nerve on the same side as the lesion. Also called crossed hemiplegia, stauroplegia.
- Alternating light
a beacon showing different colors in succession. Historical Examples The alternating light of the candle flashed upon the body of the old woman, and he remembered all. Snarley-yow Frederick Marryat Pour into well-greased pan, alternating light and dark mixtures to give it the “marbled” appearance. Fifty-Two Sunday Dinners Elizabeth O. Hiller Thus constantly is alternating […]
- Alternating pulse
alternating pulse alternating pulse n. A pulse pattern that occurs at regular intervals but alternates between weak and strong beats; usually indicates myocardial disease. Also called pulsus alternans.