Temperature Measurement

Abstract

Accurate measurement and control of temperature is important in many areas such as in the process industry and for the characterisation of materials used in the automotive, aerospace and semiconductor industries. This contribution reviews the current status of temperature measurement. It starts after a brief introduction on the idea of temperature with the description of the main fundamental methods to measure it concentrating on the temperature range important for applications. Different variants of gas thermometry, noise thermometry and the optical methods applying Doppler‐broadening spectroscopy and thermal radiation measurement are reported. The presently adopted international temperature scales to harmonize and facilitate practical temperature measurement are following including the most frequently used practical thermometers such as resistance thermometers, thermocouples and radiation thermometers. New developments like standards based on metal‐carbon eutectic phase transitions and the proposed new definition of the Kelvin based on a fundamental constant conclude the overview.