Which device uses a change in voltage to measure temperature?

The device that uses a change in voltage to measure temperature is the thermocouple. A thermocouple operates based on the thermoelectric effect, also known as the Seebeck effect. When two dissimilar metals are joined at one end and heated, a voltage is generated that is proportional to the temperature difference between the hot junction (where the metals are joined) and the cold junction (the reference point where the temperature is measured). This generated voltage can then be interpreted to determine the temperature.

Thermistors and RTDs, while they do measure temperature using resistance changes, primarily function by altering their resistance in response to temperature changes, which is then converted to voltage in subsequent circuitry, but they themselves do not generate voltage based solely on temperature differences like a thermocouple does. Infrared sensors measure temperature by detecting infrared radiation emitted by an object, which is a different principle from measuring changes in voltage.