A circuit is a closed path used in electronics equipment to enable the conduction of electrical current to travel. An electric circuit allows for the flow of electricity from one point to another. Circuits are the pathway on which an electrical current can flow. This path begins and ends at the same point, thus making a circuit, or a loop.
There are two main types of circuits—power circuits and electronic circuits. Power circuits are used in home and office lighting systems, heating systems, and wiring systems. Electronic circuits are used to move and manage major electrical currents. In power circuits, generators start the current, and the current runs through the circuit to an office or home heating and lighting systems and appliances.
To understand how a circuit works, think of a flashlight. The circuit is open when the flashlight is switched off. This means that an electrical current will not flow from the enclosed batteries to the flashlight's light bulb. When the flashlight's switch gets turned on, there is a small metal piece inside the flashlight that physically closes the circuit gap. Thus, the flashlight then lights up, as electricity from the batteries flows to the light bulb.