Closed circuit

Closed circuit can refer to:
 * Closed-circuit television
 * Closed-circuit radio
 * Closed circuit breathing apparatus, commonly known as rebreathers for portable units, and as component parts of life-support systems for more complex equipment.
 * Closed Circuit (1978 film), a 1978 Italian film
 * Closed Circuit (2013 film), a 2013 British thriller film
 * An electric circuit is a "closed circuit" if it contains a complete path between the positive and negative terminals of its power source
 * Closed Circuit (album), a 2001 album by New Zealand composer Peter Jefferies