Thermal Sensor

A sensor is a type of transducer. Direct-indicating sensors, for example, a mercury thermometer, are human-readable. Other sensors must be paired with an indicator or display, for instance a thermocouple. Most sensors are electrical or electronic, although other types exist.

Thermocouples are a widely used type of temperature sensor and can also be used as a means to convert thermal potential difference into electric potential difference. They are cheap and interchangeable, have standard connectors, and can measure a wide range of temperatures.

A thermistor is a type of resistor used to measure temperature changes, relying on the change in its resistance with changing temperature.