Thermocouple

A thermocouple is an electrical device made of two dissimilar electrical conductors joined together at an electrical junction, which produces a voltage that depends on temperature through what is called the Seebeck effect, making the device useful as a temperature sensor. The underlying effect was discovered in 1821 by the German physicist Thomas Johann Seebeck, who found that a magnetic needle held near a circuit of two dissimilar metals was deflected when one of the metal junctions was heated, an effect he first called thermo-magnetism before it was understood to be a thermoelectric current rather than magnetism. Thermocouples are inexpensive, interchangeable with standard connectors, able to measure a wide range of temperatures, and self powered since they need no external electricity, though their main drawback is accuracy, since keeping the measurement error under one degree Celsius can be difficult. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/