Longman Dictionary of Contemporary English
The Collaborative International Dictionary
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 electric charge through conductors, whether constant or variable. Sudden movements of charge are usually referred to by other terms, such as spark or lightning or discharge. In metallic conductors the electric current is usually due to movement of electrons through the metal. The current is measured as the rate of movement of charge per unit time, and is counted in units of amperes. As a formal definition, the direction of movement of electric current is considered as the same as the direction of movement of positive charge, or in a direction opposite to the movement of negative charge. Electric current may move constantly in a single direction, called direct current (abbreviated DC), or may move alternately in one direction and then the opposite direction, called alternating current (abbreviated AC).
Wiktionary
n. an electric current in which the direction of flow of the electrons reverses periodically 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.
WordNet
n. an electric current that reverses direction sinusoidally; "In the US most household current is AC at 60 cycles per second" [syn: AC] [ant: direct current]
Wikipedia
Alternating current (AC), is an electric current in which the flow of electric charge periodically reverses direction, whereas in direct current (DC, also dc), the flow of electric charge is only in one direction. The abbreviations AC and DC are often used to mean simply alternating and direct, as when they modify current or voltage.
AC is the form in which electric power is delivered to businesses and residences. The usual waveform of alternating current in most electric power circuits is a sine wave. In certain applications, different waveforms are used, such as triangular or square waves.
Audio and radio signals carried on electrical wires are also examples of alternating current. These types of alternating current carry information encoded (or modulated) onto the AC signal, such as sound (audio) or images (video). These currents typically alternate at higher frequencies than those used in power transmission.
Usage examples of "alternating current".
One day industry will need the kind of high voltages and transformers only alternating current can supply.
He shares credit with his student, Marconi, for the invention of radio and he also discovered alternating current.
We also have electric waves, the waves of the alternating current, and shorter still we find the Hertzian waves, which are used in wireless.
Even my friend George Westinghouse, who had become rich from my patents for alternating current motors and generators, declined to help me.
Generals planned strategic air strikes beneath the no-nonsense glow of alternating current, and it was all out of control, like a kid's soapbox racer going downhill with no brakes: I was following my orders.
The alternating current is not adapted to reproduce speech, but the ordinary direct current is.
Your species has developed an extensive system of engineering using alternating current.
Besides their structures, the Alphanes had left nut-sized crystals which formed holograms in the air above them when subjected to alternating current.
At the designated hour, an electrician throws a switch and a high-voltage alternating current surges through your body for two or three minutes -- typically starting at 2,000 volts at 5 amps, with the voltage varied periodically.
It is alternating current of sixty cycles at two hundred and twenty volts.
Any electric motor, not just the one in a razor, converts an alternating current into an alternating magnetic field.
Upon careful inspection there seemed to be no doubt that it was some kind of spark induction device in other words, where a low-tension alternating current was transformed to a high-tension alternating current, with the spark-gap built into the secondary lead.
Fluctuations, like a sort of alternating current passing through him, would interrupt the clutch of his arms each time.
I pictured something like the stupendous Wardenclyffe power tower that Nikola Tesla-the discoverer of alternating current- built out at Shoreham back in 1901, ready to hurl fire at the heavens.