Thermal Converter

an electrical circuit or part of a circuit that is composed of unlike conductors or semiconductors and that makes possible the practical application of one of the thermoelectric effects.

If the junctions of a thermal converter are maintained at different temperatures, an electromotive force (the thermal emf) arises in the circuit; if the circuit is closed, an electric current appears. This phenomenon, the Seebeck effect, is used primarily for the measurement of temperature or of other physical quantities whose measurement may be reduced to a temperature measurement—for example, gas pressure, the rate of flow of a liquid or gas, humidity, radiant energy flux, and the strength of industrial-frequency alternating current and radio-frequency currents. (In all these cases, the thermal converter serves as a thermal measuring transducer.) Thermal converters designed for measurement technology are usually called thermocouples. Semiconductor thermal converters based on the Seebeck effect are also used in thermoelectric power generators, which convert the heat energy of fuel, radioactive decay, or solar radiation into electric power.

If a current from an outside source is passed through a thermal converter, heat is absorbed at one of the converter’s junctions and is released at the other. The operation of some thermoelectric coolers, airconditioners, and thermostats is based on this phenomenon (the Peltier effect); such devices are used in the home and in electronics, medicine, and electrical engineering.