While simple in form and function, thermocouples must be right for the application and handled with care for optimum performance and accuracy.

The most common sensor in a thermal system is a thermocouple (TC), which is sensitive to a change in process conditions, reasonably accurate and offers the required precision at a modest cost. Thermocouples are rugged and can be used over a wide range of process temperatures-from subzero to over 4000F (2205C). However, a combination of many factors influence the successful application of a thermocouple, including thermocouple material purity and manufacturing quality, temperature exposure, thermal cycling, chemical exposure, the protection applied and physical abuse. This article provides a perspective on the selection and application of thermocouples.