Circuit Symbols
Circuit diagrams are used to show how electrical components are connected together. Each electrical component has its own symbol. In order to draw basic circuit symbols it is important you learn the following symbols.
| Component | Symbol | Function |
| Wire |  |
Made from a metallic conductor so current can easily pass from one part of the circuit to another
| Switch (open) |  |
On/Off switch – in open position the circuit is broken so no current flows
| Switch (closed) |  |
On/Off switch – in closed position the circuit is complete and current flows
| Cell |  |
Supplies the electrical energy to the circuit – the larger terminal on the left is the positive (+) terminal
| Battery |  |
A battery is more than one cell.
| Lamp |  |
Coverts electrical energy to light.
| Fuse |  |
A safety device which melts to break the circuit if the electrical current flowing through it exceeds a specified value.
| Voltmeter |  |
Instrument used to measure potential difference.
| Ammeter |  |
Instrument used to measure electrical current
| Resistor |  |
Restricts the flow of electrical current can be used to limit the flow of current to a particular component
| Diode |  |
A device which only allows current to flow in one direction
| Thermistor |  |
Converts heat to electrical resistance
| Variable resistor |  |
Used to control current
| Light dependant resistor |  |
Converts light to electrical resistance