Ampere Ampere The ampere (; symbol: A), often shortened to "amp", is the base unit of electric current in the International System of Units (SI). It is named after André-Marie Ampère (1775–1836), French mathematician and physicist, considered the father of electrodynamics. The International System of Units defines the ampere in terms of other base units by measuring the electromagnetic force between electrical conductors carrying electric current. The earlier CGS measurement system had two different definitions of current, one essentially the same as the SI's and the other using electric charge as the base unit, with the unit of charge defined by
Watt example "gigawatt electrical" (GW). The International Bureau of Weights and Measures, which maintains the SI-standard, states that further information about a quantity should not be attached to the unit symbol but instead to the quantity symbol (i.e., "P" = 270 W rather than "P" = 270 W) and so these units are non-SI. In compliance with SI the energy company DONG Energy uses the unit megawatt for produced electrical power and the equivalent unit megajoule/s for delivered heating power in a combined heat and power station such as Avedøre Power Station. When describing alternating current (AC) electricity, another distinction is