Electrical Circuit Symbols

Below are some common symbols which represent components that can be found in an electrical circuit.


A switch is used to complete or break a circuit.

  • Closing a switch completes the circuit
  • Opening a switch breaks the circuit

Switches allow us to use devices when we need them and turn them off after.


Cells power a circuit, providing the potential difference. This drives the charge that flows around the circuit.

  • They store chemical energy


Batteries are two or more cells in a circuit that are connected in series with each other,


A diode converts an alternating current to a direct current, which allows the current to flow in one direction. There are different types of diodes.


When energy passes through a lamp, it gives out light. This is due to a thin filament that gets heated by the electrical current, which makes it glow.


A fuse is a safety component. It contains a wire with a lower melting point. So if the current gets too high, the wire melts and this breaks the circuit.

Breaking the circuit prevents the high current from forming fires and damaging other components.

Fixed resistor

A resistor is a component that restricts the flow of electric current. A fixed resistor has a resistance that cannot be changed.

  • They are often used to protect sensitive devices from large currents

Variable resistor

A variable resistor is a type of resistor that lets you can change the resistance.

  • They can be used for dimming lights


Voltmeters are used to measure the potential difference across different components. They are always placed in parallel to the component being measured.

  • They must have a high resistance, so hardly any current flows through it


An ammeter is used to measure the current flowing through a circuit. They are always placed in series with the circuit.

  • The resistance of an ammeter must be very close to zero, which prevents it from affecting the current reading.


Thermistors are temperature-dependent resistors. As the temperature around a thermistor increases, the resistance of the thermistor decreases.

  • Thermistors can be used as temperature sensors. They are often found in appliances, such as fire alarms and thermostats

Light-dependent resistor (LDR)

As you increase the light intensity, the resistance of a light-dependent resistor decreases.

  • LDRs are often found in sensors, such as cameras, light intensity meters and automatic lighting. This makes them useful for burglar alarms.