Series and Parallel Circuits

This lesson covers the rules for series and parallel circuits, including how current, potential difference and resistance behave in each type of circuit. This is a core part of the AQA GCSE Physics specification (4.2.1.4) and is heavily examined.

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Series Circuits

In a series circuit, all components are connected one after another in a single loop. There is only one path for the current to follow.

graph LR
    A[Battery] --> B[Lamp 1]
    B --> C[Lamp 2]
    C --> D[Lamp 3]
    D --> A

Current in Series Circuits

The current is the same at every point in a series circuit. This is because there is only one path for the charge to flow through — the same charge passes through every component.

I(total) = I(1) = I(2) = I(3)

If you place ammeters at different points in a series circuit, they will all read the same value.

Potential Difference in Series Circuits