The thermocouple circuit which is used to measure temperature works on the principle of measuring the voltage difference between two junctions.

A thermocouple is a device that measures temperature. It works by using a small voltage generated by a thermoelectric effect. This voltage difference can be measured and converted into a temperature reading.

The circuit used to measure temperature using a thermocouple consists of two junctions, one at each end of the device. One junction is made from nichrome wire, while the other junction is made from platinum wire. The nichrome wire acts as the hot junction, while the platinum wire acts as the cold junction.