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Voltmeter

Key Stage 3

Meaning

A picture showing an analogue voltmeter.

A voltmeter is a measuring device used to measure the potential difference between two points in a circuit.

About Voltmeters

Voltmeters are added in parallel to components in a circuit to find the potential difference between two points.
An ideal voltmeter has infinite resistance because otherwise adding an voltmeter to a circuit would change the Potential Difference between two points.
Voltmeters can be analogue with a needle pointing to numbers on a dial or it can be digital with a number display.
Circuit+Diagram3.png
A voltmeter placed in parallel with a bulb.

Key Stage 4

Meaning

A voltmeter is a measuring device used to measure the potential difference between two points in a circuit.

About Voltmeters

Voltmeters are added in parallel to components in a circuit to find the potential difference between two points.
An ideal voltmeter has infinite resistance because otherwise adding an voltmeter to a circuit would change the potential difference between the two points.
Voltmeters can be analogue with a needle pointing to numbers on a dial or it can be digital with a number display.
Using a voltmeter on components in series.
CircuitDiagramBatteryBulbBulbSeries.png
CircuitDiagramBatteryBulbBulbSeries.png
To measure the potential difference across bulb 1 the voltmeter must be placed in parallel with bulb 1. To measure the potential difference across bulb 2 the voltmeter must be placed in parallel with bulb 2.
CircuitDiagramBatteryBulbVoltmeterBulbSeries.png
CircuitDiagramBatteryBulbBulbVoltmeterSeries.png
Using a voltmeter on components in parallel.
CircuitDiagramBatteryBulbBulbParallel2.png
CircuitDiagramBatteryBulbBulbParallel2.png
To measure the potential difference across bulb 1 the voltmeter must be placed in parallel with bulb 1. To measure the potential difference across bulb 2 the voltmeter must be placed in parallel with bulb 2.
CircuitDiagramBatteryBulbVoltmeterBulbParallel.png
CircuitDiagramBatteryBulbBulbVoltmeterParallel.png
In this case both voltmeters will give the same measurement because the components themselves are in parallel.

References

AQA

Voltmeter, pages 52-3, 56, GCSE Physics; Student Book, Collins, AQA
Voltmeters, page 239, GCSE Combined Science; The Revision Guide, CGP, AQA
Voltmeters, page 41, GCSE Physics, Hodder, AQA
Voltmeters, page 52, GCSE Physics; Third Edition, Oxford University Press, AQA
Voltmeters, pages 25, 106, GCSE Physics; The Revision Guide, CGP, AQA
Voltmeters, pages 293, 296, GCSE Combined Science Trilogy 1, Hodder, AQA
Voltmeters, pages 60, 61, 235, GCSE Combined Science Trilogy; Physics, CGP, AQA
Voltmeters, pages 62, 63, 331, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
Voltmeters; calibration of, page 316-17, GCSE Combined Science Trilogy 1, Hodder, AQA
Voltmeters; calibration of, pages 64-5, GCSE Physics, Hodder, AQA
Voltmeters; circuit symbol, page 38, GCSE Physics, Hodder, AQA

Edexcel

Voltmeters, page 143, GCSE Physics, Pearson Edexcel
Voltmeters, pages 186, 210, GCSE Combined Science; The Revision Guide, CGP, Edexcel
Voltmeters, pages 220, 338, 339, GCSE Physics, CGP, Edexcel
Voltmeters, pages 73, 106, GCSE Physics; The Revision Guide, CGP, Edexcel

OCR

Voltmeters, pages 101-103, 259, Gateway GCSE Physics, Oxford, OCR
Voltmeters, pages 178, 224, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR
Voltmeters, pages 45, 49, 105, Gateway GCSE Physics; The Revision Guide, CGP, OCR