Contents
Key Stage 3
Meaning
A Parallel Circuit is an electrical circuit with two or more paths the current can flow along.
About Parallel Circuits
- In a parallel circuit the current is split at junctions before taking a different path.
- Switches can be placed in a Parallel Circuit to allow current along one path at a time.
- Components placed in parallel with each other have the same Potential Difference across them.
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| The current from the battery splits at the junction sharing the current between the two bulbs. | The two bulbs in this parallel circuit can be switched on and off separately. |
Examples
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| 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 bulb and motor are in parallel so they have the same potential difference across them but may have a different current passing through them. |
Key Stage 4
Meaning
A Parallel Circuit is an electrical circuit with two or more paths the current can flow along.
About Parallel Circuits
- In a parallel circuit the current is split at junctions before taking a different path.
- Switches can be placed in a parallel circuit to allow current along one path at a time.
- Components placed in parallel with each other have the same potential difference across them.
| |
|
| The current from the battery splits at the junction sharing the current between the two bulbs. | The two bulbs in this parallel circuit can be switched on and off separately. |
Examples
| |
|
|
| 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 bulb and motor are in parallel so they have the same potential difference across them but may have a different current passing through them. |
Resistors in Parallel
NB: You only need to know what happens with identical resistors in parallel.
- When identical resistors are added in parallel there are more paths for the electricity so the resistance is reduced.
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| Two identical resistors in Parallel circuit gives twice the number of paths, so has half the resistance.
The resistance between points A and B is 12Ω. |
Three identical resistors in Parallel circuit gives three times the number of paths, so has a third of the resistance.
The resistance between points A and B is 8Ω. |
Four identical resistors in Parallel circuit gives four times the number of paths, so has a quarter of the resistance.
The resistance between points A and B is 6Ω. |