Electric current electrons into the conduction band. The current-carrying electrons in the conduction band are known as "free electrons", though they are often simply called "electrons" if that is clear in context. Current density is a measure of the density of an electric current. It is defined as a vector whose magnitude is the electric current per cross-sectional area. In SI units, the current density is measured in amperes per square metre. where "formula_6" is current in the conductor, formula_7 is the current density, and formula_8 is the differential cross-sectional area vector. The current density (current per unit area) "formula_7" in materials
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