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.

Joseph James "Joe" Rogan (born August 11, 1967) is an American martial artist, stand-up comedian, actor, writer and color commentator. He is best known for playing Joe Garrelli on the NBC sitcom NewsRadio, commentating for the Ultimate Fighting Championship, hosting the NBC reality show Fear Factor and The Joe Rogan Experience podcast.

Rogan was born in Newark, New Jersey. His paternal grandfather was Irish and the remainder of his ancestry is Italian.

In 1981, at age fourteen, he became a practitioner of Kenpo Karate before transitioning to Taekwondo. He eventually gained a 2nd dan black belt. A four-time state champion in Massachusetts, in 1987 he was the USA Taekwondo U.S. Open Champion. In 1996, he began training in Brazilian Jiu-Jitsu under Jean Jacques Machado, eventually earning his brown belt. In addition, he holds a brown belt in 10th Planet Jiu-Jitsu under Eddie Bravo.

He also practiced and competed in kickboxing.

In 1994, he co-starred on the Fox comedy Hardball as Frank Valente, the young, ego-centric star player on a fictional professional baseball team. From 1995 to 1999, he co-starred on the comedy NewsRadio. He portrayed Joe Garrelli, the electrician at WNYX, a news radio station in New York City. In 2002, he appeared on the episode "A Beautiful Mind" of Just Shoot Me as Chris, Maya Gallo's boyfriend. In 2011, Rogan played his first major character in a movie in the Kevin James movie Zookeeper. He is slated to play himself in an upcoming action-comedy starring Kevin James called Here Comes the Boom, set to be released in the summer of 2012.