alternating current

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current

 [kur´ent]
1. something that flows.
2. specifically, electricity transmitted through a circuit.
alternating current a current that periodically flows in opposite directions; its amplitude fluctuates as a sine wave.
convection current a current caused by movement by convection of warmer fluid into an area of cooler fluid.
direct current a current that flows in one direction only; when modeled as a wave, its amplitude is constant. When used medically it is called galvanic current. This current has distinct and important polarity and marked secondary chemical effects.
galvanic current a steady direct current.
current of injury an electric current that flows between injured myocardium and normal myocardium, because such cells have a reduced membrane potential; it may be either diastolic or systolic.
current of injury, diastolic the current that flows from injured to noninjured tissue during electrical diastole.
current of injury, systolic the current that flows from healthy tissue to injured tissue during electrical systole.
inwardly rectifying current current that rectifies so that it passes more easily towards the interior of a cell.
leakage current the electrical current that exists in the parts or metal case of electrical equipment.
outwardly rectifying current current that rectifies so that it passes more easily towards the exterior of a cell.
potassium rectifying c's transmembrane currents that rectify inwardly or outwardly to make adjustments in cellular functions; they are mainly responsible for the repolarization phase of the action potential. There are at least six mechanisms by which potassium ions move across cardiac cell membranes in the role of rectifier.

al·ter·nat·ing cur·rent (AC),

a current that flows first in one direction then in the other, for example, 60-cycle current.

alternating current

An MRI term for a continuously changing flow of electrons that alternates its polarity at a periodic rate. In the US, the current changes at a frequency of 60 Hz.

al·ter·nat·ing cur·rent

(AC, ac, a.c.) (awl'tĕr-nāt-ing kŭr'rĕnt)
Electric current that reverses direction (positive-negative polarity) many times each second (with each rotation of the armature of the dynamo generating the current).

al·ter·nat·ing cur·rent

(AC, a.c.) (awl'tĕr-nāt-ing kŭr'rĕnt)
Electric current that reverses direction (positive-negative polarity) many times each second (with each rotation of the armature of the dynamo generating the current).
References in periodicals archive ?
The effect of direct current on the human being is less harmful than that of alternating current. Moreover, the number of direct current electric shock incidents is much lower than that of alternating current incidents, which is due to the much smaller number of appliances and devices powered by direct current.
Edison not wanting to lose the royalties he was earning from his direct current patents began a campaign to discredit alternating current. He spread misinformation saying that alternating current was more dangerous even going so far as to publicly electrocute stray animals using alternating current to prove his point.
(However, this analogy is somewhat like comparing apples and oranges, since Earth's magnetic field is static, while those due to alternating current oscillate at one or more characteristic frequencies.) Overall, EPRI observed considerable variation between homes, with some 5 percent of those surveyed registering background averages of at least 2.7 mG.
Then alternating currents over one of four ranges (0-2 A with 1 mA resolution, 0-20 A with 10 mA resolution, and 0-50 A or 0-100 A with 100 mA resolution) can be measured.

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