1. IP2.18.3 Circuit symbols © Oxford University Press 2011 Circuit symbols

2. IP2.18.3 Circuit symbols © Oxford University Press 2011  Circuit symbols are used to show the different components in a circuit.  The main reasons scientists use circuit symbols are:  They are much simpler to draw than trying to reproduce an accurate sketch of each component.  Each different type of component has its own distinct symbol which is easy to recognise. This means that the correct components can be identified easily.  The symbols are an almost universal language so it doesn’t matter what language you speak – the symbols are the same.

3. IP2.18.3 Circuit symbols © Oxford University Press 2011 open switch closed switch An on-off switch allows current to flow only when it is in the closed (on) position

4. IP2.18.3 Circuit symbols © Oxford University Press 2011 Cell Supplies electrical energy. Larger terminal is positive. Normally 1.5 V.

5. IP2.18.3 Circuit symbols © Oxford University Press 2011 Battery Supplies electrical energy. Made up of multiple cells

6. IP2.18.3 Circuit symbols © Oxford University Press 2011 Diode A component that only allows current to flow in one direction.

7. IP2.18.3 Circuit symbols © Oxford University Press 2011 Resistor Restricts the flow of current in a circuit.

8. IP2.18.3 Circuit symbols © Oxford University Press 2011 Variable resistor A component used to vary and control the current in a circuit.

9. IP2.18.3 Circuit symbols © Oxford University Press 2011 Lamp A component that transforms electrical energy into light.

10. IP2.18.3 Circuit symbols © Oxford University Press 2011 Fuse A safety device that will break the circuit and stop current flowing if the current flowing through it exceeds a specified value.

11. IP2.18.3 Circuit symbols © Oxford University Press 2011 Voltmeter Ammeter Used to measure potential difference (voltage) between two points in a circuit. Used to measure current in a circuit.

12. IP2.18.3 Circuit symbols © Oxford University Press 2011 Thermistor A component whose resistance is related to temperature

13. IP2.18.3 Circuit symbols © Oxford University Press 2011 Light-dependent resistor (LDR) A component whose resistance is related to the amount of light falling on it.

14. IP2.18.3 Circuit symbols © Oxford University Press 2011 Light-emitting diode (LED) A component that transforms electrical energy into light.