OCR AS Physics

Revision Notes

4.3.6 Series & Parallel Circuits

Analysing Series & Parallel Circuits


  • In a series circuit, the current is the same for all components
  • In a parallel circuit, the current is split across the different branches (or junction). The total current into a junction must equal the total current out of a junction
    • The amount of current in each branch depends on the total resistance of the components within that branch

Potential Difference

  • In a series circuit, the e.m.f of the power supply is shared amongst all the components in different amounts, depending on their resistance
  • In a parallel circuit, the voltage of all the components in each branch is equal to the e.m.f of the power supply



  • A summary of the current, voltage and resistance within a series and parallel circuit are summarised below:

Table of Voltage, Current & Resistance in Series & Parallel Circuits

Series & Parallel Circuits Summary Table, downloadable AS & A Level Physics revision notes

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