GCSE Combined Science (AQA)

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Ohmic Conductors

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Electricity Current, potential difference and resistance

Ohmic Conductors

4:25 Resistance of Circuit Components
Spec 4.2.1.4
Previous Measuring Resistance Next Filament Lamps
  • An Omic conductor has constant resistance at constant temperature.
  • Resistance of a conductor increases with temperature.
  • Fixed resistors are designed to have constant resistance.
  • Wires are Omic conductors with small resistance, unchanged if not heated.
  • Omic properties can be lost at extreme temperatures, not needed for GCSE.
  • IV graph for Omic conductor is a straight line through the origin.
  • IV graphs show the relation between current and potential difference.
  • Potential difference is proportional to current for Omic conductors.
  • V = K, where K is a constant value, represents the relation.
  • V/I = K, where K is the resistance of the component.
  • R is constant for Omic conductors with a straight line IV graph.
  • Steeper gradient of the graph indicates smaller resistance.
  • Gradient is calculated by I/V, equal to 1/R.
  • Higher resistance means smaller gradient.
  • Steeper graph indicates smaller resistance, shallower graph indicates larger resistance.

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