In a temperature-controlled circuit, what happens to the thermistor's resistance as it heats up?

In a temperature-controlled circuit using a thermistor, as the temperature increases, the resistance of the thermistor decreases. This relationship is characteristic of a thermistor, particularly a negative temperature coefficient (NTC) thermistor. In an NTC thermistor, higher temperatures provide more energy to the charge carriers in the material, allowing them to move more freely. As a result, the overall resistance drops when the temperature rises.

This behavior makes thermistors particularly useful in temperature sensing and control applications because they can provide a clear and responsive change in resistance with temperature variations, enabling the circuit to adjust accordingly. The consistent decrease in resistance with increasing temperature reinforces the effectiveness of thermistors in various electronic applications, such as temperature sensors and electronic thermostats.