Thermistors and Light Dependent Resistors (LDRs)

Designed for the AQA 9-1 GCSE, this can be taught as two seperate lessons or for the more able combined into one.

Learning Objectives (AQA Specification)

• The resistance of a thermistor decreases as the temperature increases.
• The applications of thermistors in circuits e.g. a thermostat is required.
• The resistance of an LDR decreases as light intensity increases.
• Investigate the relationship between the resistance of a thermistor and temperature.

Success Criteria
Know (Grade 1-4)

• State that the resistance of a thermistor decreases as the temperature increases.
• State that the resistance of a thermistor decreases as the temperature increases.
• Recall some uses of thermistors and LDRs.
  Apply (Grade 5-7)
• Draw graphs to show how the resistance of a thermistor changes with temperature.
• Calculate the resistance of a thermistor given the range of resistances for that component and the temperature that it is placed in.
• Draw graphs to show how the resistance of an LDR will vary with light intensity.
• Calculate the resistance of an LDR given the range of resistances for that component and the conditions that it is placed in.
  Extend (Grade 8+)
• Describe and explain real world applications of thermistors and LDRs including thermostats and switching on lights when it gets dark.

Images that are not my own are referenced in the notes.