Investigating Thermistors: Resistance and Temperature

Investigating Thermistors: Resistance and Temperature is a free interactive simulation of an NTC thermistor for GCSE Physics (Edexcel IGCSE 4PH1). Students change the water bath temperature and measure the thermistor's resistance with an ohmmeter to investigate how the two are related. No login required — includes a worksheet and self-marking quiz.

Aim: To investigate how temperature affects the resistance of an NTC thermistor.

Water bath
806040200
heater
OHMMETER
Ω
kΩ

Results table

Temperature (°C) Resistance (kΩ) Action

Part A — Collecting resistance vs. temperature data

  1. Set the water temperature to 0°C using the slider, then read the resistance shown on the ohmmeter. Record both values as a row in the results table.
  2. Repeat at several more temperatures, spreading your choices evenly across the full 0–80°C range, until you have at least 6 rows of data.
  3. Plot a graph of resistance (y-axis) against temperature (x-axis) using your results. Describe the shape of your graph.

Part B — Interpreting the trend

  1. Compare how much the resistance changes between 0°C and 20°C with how much it changes between 60°C and 80°C. Is the thermistor equally sensitive across the whole range, or more sensitive at some temperatures than others?
  2. An NTC thermistor's resistance falls as its temperature rises because heating frees more charge carriers inside the semiconductor. Using your graph, explain why this makes a thermistor useful as the sensing element in a thermostat.