The components of an electrical circuit

The essential components

A simple electrical circuit is made up of several types of components, each with a specific role.

Component	Role	Example
Power source	Supplies electrical energy	Battery
Load	Converts electrical energy	Light bulb, motor, buzzer
Wires	Allow current to flow	Copper wires
Switch	Opens or closes the circuit	Push-button, switch

The standardised diagram

In physics, we do not draw real objects but standardised symbols, which are identical throughout the world. For example, a battery is represented by two lines (one long and one short), and a lamp by a circle containing a cross.

This makes it possible to read a circuit diagram quickly and unambiguously, regardless of the reader’s country or language.

Conductors and insulators

The wires used in a circuit are made of conductive materials (such as copper or aluminium), which allow electric current to flow. Conversely, an insulating material (such as plastic or rubber) prevents current from flowing: this is why electrical wires are always covered with a plastic sheath.

A common pitfall to avoid

A generator on its own, without a load, must never be connected directly by a single wire between its two terminals: this is called a short circuit. The current then becomes very strong, the battery heats up and can be damaged quickly. There must always be a load (such as a light bulb) to limit the flow of current in the circuit.