It is specially designed for petrochemical industry to directly measure the temperature of liquid, vapor, gas and solid surface ranging from -200°C to 1600°C.
Thermocouple electrodes are made of two different materials. Temperature difference between measuring end and reference end results in pyroelectric potential, then display meter indicates the corresponding temperature to the pyroelectic potential.
It is based on that temperature change of material results in change of its resistance. When resistance value changes, the working instrument will display relevant temperature value.