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Potentiometer

Physics: Cambridge International GCSE Supplement, topic 4.9.1

Potentiometer

A potentiometer is a component that divides the potential difference (energy driving charge round the circuit) within a circuit.

Potentiometer

Potentiometer

  • A potentiometer is made of a variable resistor connected in series with a resistor and an energy source.
  • The e.m.f. of the energy source is fixed.
  • Adding the potential differences across the resistors will equal the e.m.f. of the energy source.
  • The potential difference is the work done by a unit charge passing through a component.
  • The e.m.f. is the electrical work done by a source in moving a unit charge around a complete circuit.
Potential difference

Potential difference

  • Increasing the resistance of the variable resistor increases the potential difference across variable resistor, labelled V2.
  • Because the potential difference across the two components adds up to a fixed value, the potential difference across the other resistor, labelled V1 will fall to make up for this.

Test yourself on Potentiometer

  • Which of these is not required to make a potentiometer?

  • What will happen if the resistance of the variable resistor is decreased?

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