What does a thermocouple do?

A thermocouple is a device that converts thermal energy into electrical energy. It operates on the principle of the Seebeck effect, which occurs when two different metals are joined at two junctions. When there is a temperature difference between these junctions, a voltage is produced that can be measured as an electrical signal. This ability to generate a voltage response to temperature changes enables thermocouples to detect and measure temperature effectively.

While thermocouples can be associated with the generation of a small DC current as a byproduct of their operation, their primary function is not to generate current but rather to sense and detect temperature changes. This makes the capability of detecting temperature variations the most accurate description of a thermocouple’s fundamental purpose.