Contents
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.
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| 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.
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| 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. |
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| 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. |
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| In this case both voltmeters will give the same measurement because the components themselves are in parallel. | |