GCSE Physics · AQA 8463 · Topic 4.2.2
Series and parallel circuits
Key points
- In a series circuit the current is the same through every component.
- The total potential difference of the supply is shared between the components in series.
- Total resistance in series is the sum: .
- In a parallel circuit the p.d. across each branch is the same as the supply, and the total current is the sum of the branch currents.
- Adding a resistor in parallel makes the total resistance less than the smallest single resistance, because there are more paths for the charge.
- Exam tip: when using for one component, use the current and p.d. for that component only.
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Most real circuits contain several components, either one after another (series) or side by side on separate branches (parallel). Knowing the rules for each lets you find any missing current, potential difference or resistance.
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