A thermocouple is a commonly used temperature measurement sensor that operates based on the principle of thermoelectric effect. It consists of two wires made of different metal materials, which form a thermoelectric junction at their connection point. When the thermoelectric junction is subjected to temperature changes, it generates an electromotive force (EMF) that is related to the temperature. The temperature variation can be determined by measuring the EMF.

The gas thermocouple is used as safety devices in gas appliances. Their purpose is to detect the presence of flame.

A thermopile is a type of thermal sensor that consists of multiple thermocouples connected in series. It utilizes the principle of the thermoelectric effect to combine the electromotive forces of multiple thermocouples, thereby increasing the amplitude of the output signal.