A thermocouple is a temperature sensor based on the Seebeck effect, in which joining two dissimilar metals produces a temperature-dependent EMF at their junction, formally expressed as a polynomial function of junction temperature whose coefficients depend only on the metal pair; the Peltier and Thomson effects are secondary phenomena present in the same circuit. Two governing laws — the law of intermediate metals and the law of intermediate temperatures — allow thermocouple circuits with additional junctions or reference temperatures to be analyzed without new calibration, and because the sensor's output depends on the difference between a hot (measuring) junction and a cold (reference) junction, ambient drift at the cold junction must be corrected through cold-junction compensation. This belongs to industrial instrumentation and measurement science, specifically thermoelectric temperature-sensing theory, positioned alongside thermistors and RTDs as the three principal temperature-sensing technologies.
A thermocouple is a temperature sensor based on the Seebeck effect, in which joining two dissimilar metals produces a temperature-dependent EMF at their junction, formally expressed as a polynomial f…