It is our goal to understand the origin of thermoelectric phenomena and the requirements for providing accurate temperature measurements using thermocouples. In an electrical conductor that is subject to a temperature gradient, there will beth a flow of thermal energy and a flow of electricity. These phenomena are closely tied to the behabovior of the free electrons in a metal; it is no coincidence that good electrical conductors are, in general, good thermal conductors. The characteristic behavior of these free electrons in an electrical circuit composed of dissimilar metals results in a useful relationship between temperature and emf. There are three basic phenomena that can occur in a thermocouple circuit: (1) the Seebeck effect, (2) the Peltier effect, and (3) the Thomson effect.
Under measurement conditions with on loading errors, the emf generated by a thermocouple circuit would be the result of the Seebeck effect only.