Direct current (DC) is the unidirectional flow of electric charge. Direct current is produced by sources such as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. The electric charge flows in a constant direction, distinguishing it from alternating current (AC). A term formerly used for direct current was galvanic current.

The abbreviations AC and DC are often used to mean simply alternating and direct, as when they modify current or voltage.

Direct current may be obtained from an alternating current supply by use of a current-switching arrangement called a rectifier, which contains electronic elements (usually) or electromechanical elements (historically) that allow current to flow only in one direction. Direct current may be made into alternating current with an inverter or a motor-generator set.

The Grid are an English electronic dance group, consisting of Richard Norris and David Ball (formerly of Soft Cell), with guest contributions from other musicians. They are best known for the hits "Swamp Thing", "Crystal Clear", "Rollercoaster", "Floatation", and "Cybernetic" (with Robert Fripp and Phil Manzanera).

The Grid formed in 1988 and had their first success with debut single, "Floatation", released on East West Records in 1990. They went on to release a string of ten UK hit singles and four albums, and toured the UK, Europe, Asia and Australia. The group's 1994 album Evolver reached #14 in the UK Albums Chart. The lead single from this album, "Swamp Thing", featuring elaborate banjo lines played by Roger Dinsdale. "Swamp Thing" proved to be a commercial success in the UK, Europe and Australia, reaching #3 in the UK and Australia and selling a total of one million copies.^{[citation needed]}

In 1996, Norris and Ball agreed to a hiatus period in order pursue individual music interests. Norris formed the Droyds, which went on to remix tracks by musicians including Armand Van Helden and Siobhan Fahey, and wrote the official biography of Paul Oakenfold (published in 2007): Ball reformed Soft Cell with Marc Almond, and also wrote music scores for films.^{[citation needed]} Norris has since formed the psychedelic duo, Beyond The Wizard's Sleeve, with DJ Erol Alkan, and has released a number of solo records and remixes under the name The Time and Space Machine.