What is a Pyrometer? Types, Advantages, Applications

Written by Dr. Bhargav Raval | Updated: September 23, 2025

Introduction

The term “pyrometer” doesn’t seem to fit. Categories, Pros, Possibilities, Uses, etc.

The ability to accurately gauge temperatures is essential in virtually every market. The accuracy of a thermometer is crucial for this task.

A pyrometer is a thermometer that measures extremely high temperatures without touching the object being measured. The pyrometer reads the temperature by detecting the object’s thermal radiation.

The pyrometer has several useful functions, including

Temperature detection without touching the object

Quick and simple measurements in inaccessible areas

Extremely Accurate and Dependable Temperature-Measuring Equipment

The Meaning of a Pyrometer

A pyrometer is an instrument for measuring extreme temperatures. A pyrometer’s ability to read temperatures without touching the thing being tested is because it uses the principle of radiation or heat from the object’s body to do so.

A pyrometer, in the modern sense, is a device that measures the surface temperature of an object without actually touching it.

Pyrometers, categorized as Optical and Radiation/Infrared, use different technologies for temperature measurement. Optical pyrometers include components like a lens, observer, adjustable lamp, ammeter, absorption screen, and red filter. They measure an object’s temperature by comparing its emitted radiation’s brightness to a known-temperature reference lamp. The optical lens collects light, concentrating heat from the lamp’s emission. The viewer measures the filament’s intensity, superimposing the source temperature on the reference lamp. Adjusting the rheostat fine-tunes the observer’s reading. Optical pyrometers are effective for accurate temperature measurements based on emitted radiation intensity.

Advantages

It’s easy to transport and assemble.
Offers a high degree of precision with a tolerance of 5 C.
There is no requirement for physical touch when taking a temperature reading.
Useful for monitoring the temperatures of in-transit items.
It is simple to implement wherever a direct physical measurement of temperature is feasible.

Disadvantage

Since the method relies solely on the intensity of the light, it can only be used to take accurate readings at relatively high temperatures.

Thermograph, Infrared/Radiation

The radiation pyrometer’s optical system includes the lens, mirror, and focusable eyepiece depicted in the picture. The optical lens acts as a conductor, sending the heat energy to the mirror. The energy is concentrated on the detector by the mirror.

Thermopiles or photomultiplier tubes can be used as the detector. When compared to the thermopile, photomultiplier tubes are lightning-fast. As a result, photomultiplier tubes make rapid temperature measurements possible. The gathered thermal energy is then transformed into an electrical current signal by the detector and sent to the control unit or temperature display.