alternating current


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Related to alternating current: direct current

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 IEC 479-1 report specifies time/current zones of the effects of alternating currents (15 to 100 Hz) and of direct currents passing along the left hand to both feet path.
In this study from Johns Hopkins, heart rhythm physicians discovered that high-frequency alternating current can stop disorderly electrical waves in the heart and restore normal heart rhythm.
When we casually flip on a light switch, the miracle of alternating current stays with us.
Hoar mentions Edison's experimentation with AC by executing stray cats and dogs to prove how unsafe AC was, without mentioning that the inventor of the revolutionary alternating current was Nikola Tesla.
This argument was rejected, with the Appeals Court citing cases dealing with costs of (1) building a filtration plant to comply with antipollution laws and (2) converting electricity from direct current to alternating current.
EMFs are invisible fields produced by the flow of electrical charges in an alternating current and are generated by anything powered by electricity, such as electric blankets, televisions and alarm clocks.
The German Government has subsidised the installation as an experiment, and the architect hopes that the system will be so efficient that it will be possible to feed power (after rectification to alternating current) back into the national grid.(2)
Alternating current didn't seem as useful as direct current, but then in 1883 a Croatian electrical engineer, Nikola Tesla (1856-1943), constructed an induction motor that could make use of alternating current to do useful work.
In general, they operate from a source of alternating current, perform the function of rectification to direct current and then are employed to provide power for a single operation.
His topics include direct current circuit analysis and basic electronic devices, alternating current fundamentals, the power factor, electric motors and generators, electrical and controls drawings, and illumination and lighting system design.
When magnetite nanoparticles are imposed to alternating current magnetic field, nanoparticles turn into powerful thermal sources that are able to degrade tumor cells.

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