# A thermistor is used in a temperature-sensing circuit. Explain how and why the current through the thermistor changes as the temperature of its surroundings increases.

> Edexcel GCSE Physics (1PH0) — 10.1 Electricity and circuits · Explain · 4 marks

> A thermistor is connected in series with an ammeter and a battery. The circuit is placed in an environment where the temperature gradually rises.

## Mark scheme (4 marks)

1. The resistance of the thermistor decreases as temperature increases
2. Current is greater when resistance is lower (linking resistance decrease to current increase)
3. Reference to potential difference (voltage) remaining the same / constant from the battery
4. Correct overall conclusion: as temperature increases, resistance decreases, so current through the thermistor increases

## Key terms

- [thermistor](https://www.gradenine.co.uk/glossary/thermistor)
- [current](https://www.gradenine.co.uk/glossary/current)

## Related

- [Revision notes for Edexcel GCSE Physics (1PH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-thermistor-is-used-in-a-a5a065b5) · Published by Druglandscape Ltd.