What is a thermocouple commonly used for?

A thermocouple is a type of temperature sensor that plays a key role in detecting the presence of heat. It generates a small voltage when there is a temperature difference between two junctions made from different metals. In the context of gas appliances, one of the primary functions of a thermocouple is to prove the existence of a pilot flame.

When the pilot light is lit, the heat from the flame warms the thermocouple, which generates a voltage. This voltage signals to the appliance's control system that the pilot is functioning correctly, allowing gas to flow to the main burner. If the pilot flame goes out, the thermocouple cools down, ceasing to generate the necessary voltage, which in turn shuts off the gas supply to prevent potential hazards such as gas leaks or explosions.

While thermocouples can be involved in temperature regulation, they are not typically considered a direct means of regulating temperature. Instead, they provide vital safety functions related to flame monitoring. Thus, their critical application in ensuring that a pilot flame is present makes them indispensable in gas-burning appliances.