Pyrometer Principle

A Pyrometer is a non-contacting device that intercepts and measures thermal radiations. Without making any contact with the radiating body and the process is known as pyrometry. This device is useful for determining the temperature of an object’s surface.

Pyrometer strictly works on the principle of black body radiation. Here emissivity of the target plays an important role, as it governs how bright the target appears to the pyrometer. Due to its high accuracy, speed, economy and specific advantages, it is widely being used as a standard procedure in many industrial applications.


An optical system gathers the visible and infrared energy from an object and focuses it to the detector.
The detector receives the photon energy from the optical system and converts it to an electric signal to drive a temperature display or control unit.

Pyrometers are also popularly known as Radiation thermometers. Pyro and thermo are basically words of Greek origin where the former means fire and the latter signifies hot. Hence, Pyrometers or Radiation thermometers are referred to as the devices employed to measure thermal radiations and surface temperatures.