Resistors (AQA GCSE Physics): Revision Note

Constant & Variable Resistance

• Resistors come in two types:

  • Fixed resistors

  • Variable resistors

• Fixed resistors have a resistance that remains constant

• Variable resistors can change the resistance through the circuit

  • This therefore can vary the amount of current through the circuit

• For fixed and variable resistors, once the resistance is set, it will stay at this value no matter how the current changes

• However, the resistance of components such as lamps, diodes (diodes and LEDs), thermistors and LDRs (light dependent resistors) changes with the current through the component

Fixed and variable resistor circuit symbols