Which type of temperature sensor uses two wires of different material?

The correct answer is the thermocouple. A thermocouple operates by utilizing two wires made from different metals or materials, which are joined at one end. This junction creates a thermoelectric effect when there is a temperature difference between the joined end (the measurement junction) and the other ends of the wires (the reference junction). This temperature difference generates a voltage (known as the Seebeck effect) that corresponds to the temperature difference between the two junctions, allowing for temperature measurement.

The thermocouple’s design allows it to measure a broad range of temperatures and provides quick responses to changes in temperature, making it highly versatile in various applications, from industrial processes to scientific experiments. The specific metals used in the thermocouple will determine its temperature range and sensitivity.

Other types of temperature sensors, such as RTDs (Resistance Temperature Detectors), use materials whose resistance changes with temperature, typically involving a single type of metal; thermistors are made of ceramic materials that change resistance significantly with temperature changes; and infrared sensors measure temperature without direct contact by detecting emitted infrared radiation. None of these utilize the two different materials principle like thermocouples do.