What do thermocouples require for their operation?

Thermocouples operate based on the principle of thermoelectricity, which involves two dissimilar metals. When these metals are joined at one junction, and there is a temperature difference between this junction and another junction (often referred to as the reference junction), a voltage is generated. This voltage is proportional to the temperature difference and can be measured to determine the temperature at the measuring junction. This characteristic makes thermocouples particularly valuable for temperature measurements in various applications, including refrigeration systems.

The operation of a thermocouple does not depend on a heating element or any mechanical parts such as thermopiles or bi-metallic strips. Instead, it is the interaction between the two different metal conductors that produces the electrical output, enabling the measurement of temperature changes effectively.