direct current

noun

1. Electricity. an electric current of constant direction, having a magnitude that does not vary or varies only slightly. Abbreviation: dc

noun

1. a continuous electric current that flows in one direction only, without substantial variation in magnitudeAbbreviation: DC Compare alternating current

1. An electric current that moves in one direction with constant strength. Batteries are a source of direct current. Direct current is not used for long-distance power transmission because it is difficult to step up the voltage to a level that is efficient for energy transfer and then to step the voltage back down again for safe domestic use. Compare alternating current. See Notes at current Tesla.