direct 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.

di·rect cur·rent (DC),

a current that flows only in one direction, for example, that is derived from a battery; sometimes referred to as galvanic current.
See also: galvanism.

direct current (DC)

an electric current that flows in one direction only and is substantially constant in value. Compare alternating current.

direct current

A continuous electromagnetic current that flows in only one direction.

di·rect cur·rent

(DC) (di-rekt kŭrĕnt)
An electrical current that flows only in one direction; e.g., that derived from a battery; sometimes referred to as galvanic current.

di·rect cur·rent

(DC) (di-rekt kŭrĕnt)
An electrical current that flows only in one direction; also referred to as galvanic current.

current

that which flows; electric transmission in a circuit.

alternating current
a current that flows in opposite directions sinusoidally.
direct current
a current whose direction is always the same.
References in periodicals archive ?
One more advantage claimed for brushless d-c drives is high starting torque, "A brushless d-c drive at a given horsepower will outperform a brush-type d-c of the same horsepower in terms of starting torque," says Lee.
Also, brushless d-c motors are not subject to thermal problems at very low speeds, which Lee singles out as a drawback of a-c drives.
High accuracy is said to be inherent feature of brushless d-c drives.
Lee claims that the high power factor of brushless d-c drives - 0.
Lee says that improvements in magnet technology have made brushless d-c drives more widely available.
Although he says there is no practical limit to brushless d-c motor size, Lee concedes that limitations of power-switching devices presently restrict affordable controllers to 300 hp.
A number of extruder manufacturers have reported good success with brushless d-c drives in a variety of applications.
feels that brushless d-c drives have potential in downstream equipment, such as vertical cooling stacks of cast film lines.
Although Smith says brushless d-c drives are a bit more expensive than their brush-type d-c counterparts, he adds that the difference is offset somewhat by the reduction in mechanical equipment such as gearboxes.
NRM-Steelastic, Columbiana, Ohio, initially experienced signalling problems with tach response when it first installed brushless d-c drives on a sheet line in its lab, according to process engineer Timothy Womer.
Womer feels that brushless d-c drives work well, but adds that the motors should be sized for adequate torque requirements.
Despite claims from makers of a-c and brushless d-c drives, not all extruder manufacturers are ready to write off brush-type d-c systems.