chapter  70
Thermocouple Thermometry
Pages 44

The self-generating thermocouple is one of the more widely used (but most misunderstood) sensors for routine and specialty thermometry because of its versatility, simplicity, ease of use, and low cost. It employs the Seebeck thermoelectric effect that, unlike the related Peltier and Thomson thermoelectric effects, alone converts heat to emf [1-4]. T.J. Seebeck first recognized the phenomenon in 1821.However, as a very early pioneer of electrical phenomena, he misunderstood the effect that bears his name. Seebeck monitored the magnetic symptom of current rather than voltage. He never applied it to thermometry.Seebeck and other early users could apply the effect only in closed circuits, rather than in modern current-suppressed “open-circuit” mode. Seebeck’s discovery enabled George Ohm to use thermocouples as the essential steady current source to develop his law of resistance in 1826. A. C. Becquerel recognized in 1826 that Seebeck’s discovery could be used for pyrometry, but C.S.M.Pouillet, in 1836, was the first to use the Seebeck effect for applied thermometry.