Electrical drawings

Circuit diagrams

Circuit diagrams are detailed drawings of electrical circuits for components, appliances or installations. The circuit diagram indicates how the components are connected to each other and how the circuit operates. The circuit diagram often does not look the same as the actual circuit or wiring.

Symbols are used on a circuit diagram to represent electrical/electronic components and appliances. Australian/New Zealand Standards, which are aligned to International Standards, apply to the symbols that are used on circuit diagrams. However standards have change over time and not all countries use the International Standards. You will encounter variations in symbols on different circuit diagrams.

Two sample circuit diagrams are shown below:

1. Simple diagram that shows a light switching circuit. The operation of the switch can be understood by studying the diagram.

 

2. A more complex circuit diagram showing a lighting system.