Electrical circuits, diagrams and symbols

In a nutshell

Electricity will flow around a completed circuit. When drawing electrical circuits, circuit symbols are used to represent the components and straight lines are used to represent the wires.

Electrical circuits

Electrical circuits consist of wires and components. Wires are used to connect the battery and the components in the circuit. There can be more than one component in any one circuit.

Circuit symbols

Circuit symbols represent circuit components. Instead of drawing a bulb, the symbol for a bulb is drawn instead.

These are some important circuit symbols to remember:

Circuit component	symbol	circuit component	Symbol
Battery		Bulb
Buzzer		Motor
Switch turned on		Switch turned off

Circuit diagrams

Circuit diagrams are used to draw electrical circuits. Wires are drawn as straight lines and circuit components are drawn using the circuit symbols above.

A circuit will only work if there is a complete loop. This means that there should be a wire coming from either side of the battery, connecting to both ends of a component. If there is more than one component, they should be connected by a single wire in between them so they form the loop.

Example

A complete circuit containing a battery, a bulb and a motor would look like this.

You can tell if a circuit is complete, by whether the component is working or not.

Example

A bulb in an incomplete circuit will not light up. The circuit needs to be in a complete loop for it to do so.