Physics - Thermistors and LDRs
OCR A-Level Physics 2022
Thermistors and LDRs as semiconductors
How do thermistors and LDRs work?
They have a number density that changes in response to environmental effects.
Thermistor resistance behaviour
What does the resistance-temperature graph look like for a typical thermistor?
For a typical thermistor, what does a low temperature mean?
A high resistance.
Temperature coefficients
What does a Negative Temperature Coefficient mean?
- A low temperature will have a high resistance.
- A high temperature will have a low resistance.
What does a Positive Temperature Coefficient mean?
- A low temperature will have a low resistance.
- A high temperature will have a high resistance.
Does this thermistor have a PTC or a NTC?
Does this thermistor have a PTC or a NTC?LDR behaviour and comparison
What does the light intensity vs resistance graph look like for a typical LDR?
What other component do LDRs and thermistors have the opposite IV characteristic to?
Filament Bulbs.