Thermocouple

Thermocouple, electric circuit involving two junctions between different metals, or semiconductors. These junctions create a small electromotive force (emf) in the circuit (known as the Seebeck effect). Measurement of this electromotive force provides a sensitive, if approximate, temperature reading ranging from 70°K to 1,000°K. Thermocouples can be run in reverse as small refrigerators. A number of thermocouples connected in series with one set of blackened junctions form a thermopile, which measures radiation. Thermoelectricity embraces the Seebeck and other effects relating heat transfer, thermal gradients, electric fields, and currents.

See also: Electric current.