alternating current

alternating current
an electric current that reverses direction at regular intervals, having a magnitude that varies continuously in sinusoidal manner. Abbr.: ac Cf. direct current.
[1830-40]

* * *

      flow of electric charge that periodically reverses; it starts, say, from zero, grows to a maximum, decreases to zero, reverses, reaches a maximum in the opposite direction, returns again to the original value, and repeats this cycle indefinitely. The interval of time between the attainment of a definite value on two successive cycles is called the period; the number of cycles or periods per second is the frequency, and the maximum value in either direction is the amplitude of the alternating current. Low frequencies, such as 50 and 60 cycles per second ( hertz), are used for domestic and commercial power, but alternating currents of frequencies around 100,000,000 cycles per second (100 megahertz) are used in television and of several thousand megahertz in radar or microwave communication. Cellular telephones operate at frequencies of about 1,000 megahertz (1 gigahertz). See also electric current.

* * *


Universalium. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Alternating current — (green curve). The horizontal axis measures time; the vertical, current or voltage. In alternating current (AC, also ac) the movement of electric charge periodically reverses direction. In direct current (DC, also dc), the flow of electric charge …   Wikipedia

  • Alternating current — Al ter*nat ing cur rent (Elec.) A current which periodically changes or reverses its direction of flow, especially an electric current that reverses direction sinusoidally, as is used for most domestic and industrial power requirements.… …   The Collaborative International Dictionary of English

  • alternating current — alternating currents N VAR An alternating current is an electric current that continually changes direction as it flows. The abbreviation AC is also used …   English dictionary

  • alternating current — ► NOUN ▪ an electric current that reverses its direction many times a second. Compare with DIRECT CURRENT(Cf. ↑direct current) …   English terms dictionary

  • alternating current — n. an electric current that reverses its direction periodically: abbrev. AC: cf. DIRECT CURRENT …   English World dictionary

  • alternating current — n [U] AC a flow of electricity that changes direction regularly and quickly →↑direct current …   Dictionary of contemporary English

  • Alternating Current —   [engl., Abk. AC], Wechselstrom …   Universal-Lexikon

  • alternating current — Synonyms and related words: AC, DC, absorption current, active current, conduction current, convection current, cycle, delta current, dielectric displacement current, direct current, displacement current, eddy current, electric current, electric… …   Moby Thesaurus

  • alternating current — noun an electric current that reverses direction sinusoidally In the US most household current is AC at 60 cycles per second • Syn: ↑AC, ↑alternating electric current • Ant: ↑direct current • Hypernyms: ↑electricity, ↑ …   Useful english dictionary

  • alternating current — electric current electric current, electrical current electrical current, the movement of electrically charged particles, atoms, or ions, through solids, liquids, gases, or free space; the term is usually used of relatively smooth movements of… …   The Collaborative International Dictionary of English

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”