alternating current

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noun

an electric current that reverses direction at regular intervals, having a magnitude that varies continuously in sinusoidal manner. Abbreviation: ac

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Compare direct current.

Origin of alternating current

First recorded in 1830–40

Words nearby alternating current

alternate angles, alternate history, alternate host, alternately, alternate plumage, alternating current, alternating-gradient focusing, alternating group, alternating light, alternating series, alternating voltage

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use alternating current in a sentence

One coil carries an alternating current along the length of the iron core, tinkering with the core’s magnetic state, first saturating it with magnetism and then desaturating it.
A WWII submarine-hunting device helped prove the theory of plate tectonics|Carolyn Gramling|July 2, 2021|Science News
When an electric vehicle is charged, the alternating current from the grid is converted to direct current that can be stored in its batteries.
A Small Dutch City Is Using Electric Cars to Feed the Grid|Edd Gent|May 7, 2021|Singularity Hub
The principal difference between the continuous-and alternating-current dynamo, is in the number of magnets used.
Wrinkles in Electric Lighting|Vincent Stephen
I am supposing that our plant consists of an alternating-current dynamo with a small exciter.
Wrinkles in Electric Lighting|Vincent Stephen

The study of the alternating-current arc has suggested a number of new experimental problems for investigators.
Encyclopaedia Britannica, 11th Edition, Volume 16, Slice 6|Various
The periodic variation of light in the alternating-current arc has also been the subject of inquiry.
Encyclopaedia Britannica, 11th Edition, Volume 16, Slice 6|Various
By this method the variations of electric quantities in an alternating-current arc can be watched.
Encyclopaedia Britannica, 11th Edition, Volume 16, Slice 6|Various

British Dictionary definitions for alternating current

alternating current

noun

a continuous electric current that periodically reverses direction, usually sinusoidallyAbbreviation: AC Compare: direct current

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for alternating current

alternating current

[ ôl′tər-nā′tĭng ]

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.

Cultural definitions for alternating current

alternating current

An electric current (see also current) in which the flow reverses periodically. (Compare direct current (DC).)

notes for alternating current

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.