GCSE Combined Science (AQA)

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Potential Difference

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Electricity Current, potential difference and resistance

Potential Difference

4:00 Potential Difference and Resistance
Spec 4.2.1.1 4.2.1.2 4.2.1.3
Previous Calculating Electric Current Next Resistance
  • A current requires a power source, like a cell, to flow in a circuit.
  • Chemical reactions in the cell release energy, allowing current to flow and power components like a lamp.
  • Potential difference measures the work done by a power source to make current flow.
  • Greater potential difference means more work on charge carriers and more energy.
  • Potential difference is measured in volts (V).
  • Potential difference across a component measures the work done by charge carriers passing through it.
  • Greater potential difference across a lamp means more work and energy given to it.
  • Potential difference across a lamp can equal the cell's potential difference if all energy is transferred.
  • The term "voltage" is commonly used but "potential difference" is preferred in exams and textbooks.
  • Voltmeters measure potential difference across components.
  • Voltmeters can have analog or digital displays.
  • Voltmeters should be connected in parallel to the component being measured.
  • Components are in parallel when on separate branches with no path passing through both.
  • To measure potential difference across a lamp, connect the voltmeter in parallel to it.
  • Voltmeter connection should create separate branches for the lamp and voltmeter.

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