Introduction To Electric Circuits -

: A device used to open or close the circuit path. An "open" circuit has a break that stops current flow; a "closed" circuit is a complete loop.

An electric circuit is an unbroken, closed loop of conductive material that allows electric charges (electrons) to flow continuously from a power source, through various devices, and back again. Essential Components of a Circuit Introduction to Electric Circuits

The behavior of circuits is governed by fundamental relationships between three primary variables: a basic introduction to electrical circuits : A device used to open or close the circuit path