Thermocouple: These are used to measure the temperature at a particular point.
They are manufactured by using two dissimilar materials belonging to thermoelectric series.
One is higher order element and another is a lower order element and 2 junctions are made.
One junction is kept at Ice Point and Another junction is kept at the place whose temperature is to be measured.
Due to the difference in temperature, an EMF is generated and this EMF is related to temperature.
Development of EMF due to the difference in temperature is called a Seebeck effect.
They can function on the principle of radiation. They are used to measure the temperature’s from a distance.
This is the explanation of Thermocouple, Seebeck Effect, and Pyrometers.