Circuit Symbols

• ​An electric circuit is a path for electricity to flow.

• ​All electrical devices, like phones, contain electric circuits that allow them to work.

• ​You need 3 things for an electric circuit to work:

  • ​Source of potential difference (e.g. cell)

  • ​A component (E.g. Bulb, Motor)

  • ​A complete loop

• ​Circuits are usually very complex

• ​It is important to have a clear way of showing how different components are connected together

• ​A standard set of symbols is used to represent different devices and to draw diagrams of circuits, which show how the components are connected.

​Open Switch - Breaks the circuit

Closed Switch - Completes the circuit

Lamp - Transfers energy into light and thermal energy

Cell - Provides potential difference to the circuit

Battery - 2 or more cells together

Diode - allows current to flow in ONLY one direction (infinite resistance in reverse direction)

Resistor - Provides a fixed resistance to a circuit

Variable resistor - Provides a resistance that can be changed

LED - A diode that is light-emitting when current passes through it.

Fuse - The weakest part of a circuit. The wire inside will break if the current is too high

Voltmeter - Measures the potential difference in a circuit

Ammeter - Measures the current in a circuit

Thermistor - A temperature-sensitive resistor. The resistance changes depending on the temperature

LDR - A light dependant resistor. The resistance changes as the light intensity changes