alternating current


Definition of alternating current 

: an electric current that reverses its direction at regularly recurring intervals abbreviation AC

Examples of alternating current in a Sentence

Recent Examples on the Web

George Westinghouse was mainly responsible for the U.S.’s adoption of electric power transmission using the alternating current. Thomas Gryta, WSJ, "Why Thomas Edison Would Not Be Happy About GE’s Latest Deal," 23 May 2018 During the night, workers cut a hole in the hotel's wall, dropped a cable four stories to the street below and then pulled the cable through a manhole to the New York Central Railway, which used alternating current. Judy Buchenot, Naperville Sun, "Suburban Cooks: Mints go from trash to treasured cookies," 13 July 2018 One pair emits a high-frequency alternating current, which measures the coin's surface characteristics—for example, a stamping of Washington or Jefferson. Kevin Dupzyk, Popular Mechanics, "Things Come Apart: A Pay Phone," 27 Nov. 2015 The device is subject to high internal temperatures that can damage transistors that convert lower-voltage direct current from the battery to higher-voltage alternating current for the motor. Ralph Vartabedian,, "Electrical defects cause Priuses to stall; Toyota may be bracing for a legal fight as safety worries grow," 23 Apr. 2018 This takes the 206-volt direct current (DC) from the Prius’s nickel metal-hydride battery and converts it into the three-phase 500-volt alternating current (AC) needed to drive the car’s two electric motor/generators. The Economist, "Do electric cars dream of software fixes?," 22 Apr. 2018 Whatever the mechanism, all electric motors, whether their input current is AC or DC, require an alternating current in their stator windings to make their rotors spin. The Economist, "Do electric cars dream of software fixes?," 22 Apr. 2018 The plant will create energy by converting sunlight via photovoltaic solar arrays into direct current electricity and converting it into alternating current utilizing power inverters. Austen Erblat,, "FPL gets site plan and plat approval for Westlake solar plant," 6 Apr. 2018 Direct current is the power produced by solar panels before being converted to alternating current, which powers homes, and typically is measured at a higher level than AC power due to loss from conversion. Rye Druzin, San Antonio Express-News, "San Antonio ranks 6th in U.S. solar," 4 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'alternating current.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of alternating current

1833, in the meaning defined above

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Last Updated

30 Jul 2018

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Time Traveler for alternating current

The first known use of alternating current was in 1833

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More Definitions for alternating current

alternating current


English Language Learners Definition of alternating current

: an electric current that changes its direction very frequently at regular intervals

alternating current


Kids Definition of alternating current

: an electric current that reverses its direction of flow regularly many times per second

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Spanish Central: Translation of alternating current

Nglish: Translation of alternating current for Spanish Speakers Encyclopedia article about alternating current

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