# Circuit

## Key Stage 2

### Meaning

A circuit is a loop of wire that electricity flows around.

A circuit needs to be complete otherwise electricity will not flow through it. Any break in the circuit will stop the electricity from flowing.
A circuit starts and ends at the source of power. This is usually a battery or cell but it can be a generator or Solar Cell.
 A circuit must be a complete loop without any breaks or it will not work. The break in this circuit stops it from working.

To practice building a circuit you can use a circuit simulator by clicking on the picture below.

## Key Stage 3

### Meaning

A circuit is a loop of wire that electricity flows around.

Circuits can have components in series or parallel.
Components in parallel in a circuit have the same Potential Difference across them but share the Current.
Components in series in a circuit have the same Current through them but share the Potential Difference.

### Examples

 The bulb and Ammeter are in series so they have the same Current going through them. The cell, bulb and Voltmeter are in parallel so they have the same Potential Difference across them. The two bulbs are in parallel so they have the same Potential Difference across them but may have a different Current passing through them. The motor and resistor are in series so they have the same Current passing through them but share the 1.5V Potential Difference between them. The bulb and motor are in parallel so they have the same Potential Difference across them but may have a different Current passing through them. The motor, resistor and bulb are in series so they all have the same Current passing through them but share the 1.5V Potential Difference between them.

### Energy Transfers

#### Cell

Energy is transferred electrically out of the chemical potential energy store.

#### Light Bulb

Energy is transferred electrically into the the thermal energy store of the bulb.
Energy is also transferred away from the bulb by light radiation.

#### Motor

Energy is transferred electrically into the the kinetic energy store of the motor as it speeds up.
Energy is transferred electrically into the the thermal energy store of the motor due to friction.

#### Speaker or Buzzer

Energy is transferred electrically into the the kinetic energy store of the Speaker.
Energy is also transferred away from the Speaker by sound radiation.

## Key Stage 4

### Meaning

A circuit is a loop of wire that electricity flows around.

Circuits can have components in series or parallel.
Components in parallel in a circuit have the same Potential Difference across them but share the current.
Components in series in a circuit have the same Current through them but share the potential difference.

### Examples

 This circuit can be used to plot the IV Graph for a diode. This circuit can be used to activate a lamp when it is dark. This circuit can be used to find the resistance of a wire.

### Energy Transfers

#### Cell

Energy is transferred electrically out of the chemical potential energy store.

#### Light Bulb

Energy is transferred electrically into the the thermal energy store of the bulb.
Energy is also transferred away from the bulb by light radiation.

#### Motor

Energy is transferred electrically into the the kinetic energy store of the motor as it speeds up.
Energy is transferred electrically into the the thermal energy store of the motor due to friction.

#### Electrical Heater

Energy is transferred electrically into the the thermal energy store of the heater.

#### Speaker or Buzzer

Energy is transferred electrically into the the kinetic energy store of the Speaker.
Energy is also transferred away from the Speaker by sound radiation.

### References

#### AQA

Circuits, pages 180, 185, 186, GCSE Combined Science; The Revision Guide, CGP, AQA
Circuits, pages 24-33, GCSE Physics; The Revision Guide, CGP, AQA
Circuits, series, page 185, GCSE Combined Science; The Revision Guide, CGP, AQA
Circuits; circuit diagrams, pages 60, 61, 235, GCSE Combined Science Trilogy; Physics, CGP, AQA
Circuits; circuit diagrams, pages 62, 63, 331, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
Circuits; investigating I-V characteristics, page 183, GCSE Combined Science; The Revision Guide, CGP, AQA
Circuits; investigating resistance, pages 182, 187, GCSE Combined Science; The Revision Guide, CGP, AQA
Circuits; parallel circuits, pages 72-76, 78, 79, GCSE Combined Science Trilogy; Physics, CGP, AQA
Circuits; parallel circuits, pages 74-78, 80, 81, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
Circuits; parallel, page 186, GCSE Combined Science; The Revision Guide, CGP, AQA
Circuits; parallel, page 302, GCSE Combined Science Trilogy 1, Hodder, AQA
Circuits; sensing, page 184, GCSE Combined Science; The Revision Guide, CGP, AQA
Circuits; sensor circuits, page 81, GCSE Combined Science Trilogy; Physics, CGP, AQA
Circuits; sensor circuits, page 83, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
Circuits; series circuits, pages 68-71, 77, 78, GCSE Combined Science Trilogy; Physics, CGP, AQA
Circuits; series circuits, pages 70-73, 79, 80, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
Circuits; series, pages 295, 301-2, GCSE Combined Science Trilogy 1, Hodder, AQA
Circuits; standard test circuit, page 67, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA

#### Edexcel

Circuits; diagrams, pages 219, 220, 338, GCSE Physics, CGP, Edexcel
Circuits; investigating, pages 239-241, GCSE Physics, CGP, Edexcel
Circuits; parallel, pages 235-238, GCSE Physics, CGP, Edexcel
Circuits; series, pages 231-234, GCSE Physics, CGP, Edexcel
Circuits; symbols, page 219, GCSE Physics, CGP, Edexcel

#### OCR

Circuits, pages 100-115, 263, Gateway GCSE Physics, Oxford, OCR
Circuits, pages 176, 178-182, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR
Circuits, pages 44, 45, 47-50, Gateway GCSE Physics; The Revision Guide, CGP, OCR
Circuits; Calculations, pages 110-111, Gateway GCSE Physics, Oxford, OCR
Circuits; Circuit boards, pages 104, Gateway GCSE Physics, Oxford, OCR
Circuits; Circuit diagrams, pages 260-261, Gateway GCSE Physics, Oxford, OCR
Circuits; Electrical power, pages 114-115, Gateway GCSE Physics, Oxford, OCR
Circuits; energy transferred in, pages 177, 182, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR
Circuits; energy transferred, pages 44, 50, Gateway GCSE Physics; The Revision Guide, CGP, OCR
Circuits; Light-dependent resistors, pages 109, 113, Gateway GCSE Physics, Oxford, OCR
Circuits; Model of, pages 96, Gateway GCSE Physics, Oxford, OCR
Circuits; Net resistance, pages 110-111, Gateway GCSE Physics, Oxford, OCR
Circuits; parallel circuits, page 181, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR
Circuits; Parallel circuits, pages 103, 111, 260-263, Gateway GCSE Physics, Oxford, OCR
Circuits; parallel circuits, pages 48, 49, Gateway GCSE Physics; The Revision Guide, CGP, OCR
Circuits; Potential difference, pages 100-101, 113, 260-263, Gateway GCSE Physics, Oxford, OCR
Circuits; Resistance, pages 104-105, 110-111, Gateway GCSE Physics, Oxford, OCR
Circuits; sensing circuits, page 47, Gateway GCSE Physics; The Revision Guide, CGP, OCR
Circuits; Sensing circuits, pages 112-113, Gateway GCSE Physics, Oxford, OCR
Circuits; Series circuits, pages 102-103, 110, 260-263, Gateway GCSE Physics, Oxford, OCR
Circuits; series circuits, pages 180, 181, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR
Circuits; series circuits, pages 48, 49, Gateway GCSE Physics; The Revision Guide, CGP, OCR
Circuits; symbols, page 176 Gateway GCSE Combined Science; The Revision Guide, CGP, OCR
Circuits; symbols, page 45, Gateway GCSE Physics; The Revision Guide, CGP, OCR
Circuits; Temperature measurements, pages 112, Gateway GCSE Physics, Oxford, OCR
Circuits; Thermistors, pages 108-109, 112, Gateway GCSE Physics, Oxford, OCR