Circuit

In electronics, a circuit is a closed path through which electric current can flow. It may include components such as transistors, resistors, and capacitors, but for electricity to flow through the circuit, the path must have no gap or break.

A flashlight is a simple example. Turning on the switch closes a gap in the circuit, allowing current to flow through the bulb and back to the batteries. When the switch is off, the gap stops the current, and the bulb goes dark.

In computing, circuits are found on circuit boards and inside integrated circuits, or "chips." Processors, such as the CPU and GPU, are integrated circuits that use billions of transistors to process data and perform calculations.

NOTE: Circuit diagrams (like the ones above) show conventional current flowing from a battery's positive terminal to its negative terminal. Electrons in the wires move in the opposite direction.