A circuit is a path that allows electrical current to flow in a continuous loop from a power source to a load and back to the source. There are two main types of current: direct current which flows in one direction, and alternating current where the flow of electrons constantly reverses direction. A basic circuit is composed of three main elements - a power source that provides energy, loads that consume that energy, and connectors such as wires that link the source to the loads to form a continuous loop.