Seebeck effect. It is the production of electricity from the contact between two different metals, two semiconductors, or a metal and a semiconductor, that are in the same circuit, due to the difference in temperature between them.
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- 1 Historical background
- 2 Principle of the Seebeck effect
- 3 Applications
- 4 Sources
The German physicist Thomas J. Seebeck discovered in 1820 that if the circuit is closed by the union of two different materials and this union has physical contact with an object, its temperature is seen as a potential difference that is generated in the union of the metals.
Seebeck effect principle
Seebeck effect with metal and semiconductor
By connecting two different conductors together, the temperature difference between them causes a potential difference at the contact point, which generates an electric current in the conductors that make up the circuit. The direction of flow of the emf in the case of two metals goes from the area of higher temperature to that of lower temperature and is in the order of a few microvolts per degree centigrade.
In the case of the union between a metal and a semiconductor, the direction of the emf depends on the type of material used, P or N, and can reach up to 200 microvolts per degree centigrade. Devices built on this principle are known as thermocouples.
The pairs formed by two metals are widely used for the measurement of high temperatures. In the case of pairs with semiconductors, they are very sensitive to radiation, so radiation thermometers are built with them. Semiconductor pairs are also efficient detectors of high frequency electromagnetic waves as well as infrared rays. They have the disadvantage that they can be used in a narrow range for temperature measurements.
Under this effect, the direct conversion of heat into electricity by means of thermoelectric batteries is projected . For this purpose, among the most appropriate semiconductors are selenium, bismuth tellurium and antimony.