What is the difference between series and parallel circuits?
Short answer
In a series circuit the components are connected one after another in a single loop, so the same current flows through each one and the voltage is shared between them. In a parallel circuit the components are on separate branches, so each branch gets the full voltage and the current splits between the branches.
Step by step
- Series: one path. The current is the same everywhere. The voltages across components add up to the supply voltage.
- Series: if one bulb breaks, the circuit is broken and all bulbs go out.
- Parallel: several paths. Each branch has the same voltage as the supply. The branch currents add up to the total current.
- Parallel: if one bulb breaks, the others stay on.
Worked example
Two identical bulbs on a 6 V battery
- Series: each bulb gets 3 V and both are dimmer
- Parallel: each bulb gets 6 V and both are as bright as one bulb alone
- That is why houses are wired in parallel
Common mistakes
- Saying current is used up as it goes round a series circuit.
- Saying voltage splits in a parallel circuit. It is the current that splits.
- Connecting the voltmeter in series. A voltmeter always goes in parallel across a component.
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