Working Principle of Thermocouples

The operating principle of the thermocouple is based on the Peltier effect. The thermocouple circuit consists of two metals joined together to form two junctions of different temperatures. A Peltier emf is generated due to the difference in temperatures of the two junctions of the circuit. The total emf within the circuit can be measured based on the temperature of the junctions and the properties of metals used in the circuit.