Direct Current, DC is the unidirectional flow of electric charge. DC current, by batteries, thermocouples, solar cells or commutator motor generator. Direct current can flow through the conductor such as wire, but may flow through the semiconductor, insulator, or even capable of electron or ion beam shape by vacuum. DC current is constant direction, and thus distinguished from alternating current (AC).
DC current can be called from by using rectifiers, which includes electronic components (usually) or electromechanical components a current is supplied only on alternating current electric current switching apparatus of the flow in one direction. DC current can be made into an alternating current of the inverter or the motor generator.
The first commercial power transmission (by Thomas Edison in the late nineteenth century, the development of) the use of direct current. Since the DC current significant advantages over alternate transformation and transmission, and today almost all of the AC power distribution. In the mid-1950s, HVDC transmission, is now an option, rather than the long-distance high-voltage AC power system. For applications such as DC third rail power system, AC was assigned to a substation, which uses a rectifier power is converted to direct current.
DC current to charge the battery, and in almost all electronic systems as a power source. A very large number of DC power for the production of aluminum and other electrochemical processes. DC Some railway propulsion, especially in urban areas, is used to transmit large amounts of electricity HVDC on the remote site or an AC power grid interconnection.
