The production of a voltage between dissimilar metals with their ends at different temperatures is a function of the three thermoelectric effects in metals:
- The Seebeck effect: Thomas Johann Seebeck (1770-1831) was the first person to demonstrate the thermoelectric effects of producing currents which occur in a circuit comprising two metals where the two welds are at different temperatures. He did not fail to note the phenomenon caused by a temperature difference along a homogeneous conductor; a phenomenon which would be rediscovered thirty years later by William Thomson and called the Thomson Effect.
- The Peltier effect: Jean Charles Athanase Peltier, French physicist (1785-1845), gave up the profession of watchmaker at the age of thirty to devote himself to experimental physics; he is known for his discovery in 1834 of the Peltier effect: when an electric current passes through the junction of two dissimilar metal conductors, there is a rise or fall in temperature depending on the direction of the current; the amount of heat released or absorbed is proportional to the strength of the current. It is in a sense the converse of the Seebeck effect. Passing a current can therefore cause heat to be absorbed; this effect is used in some small refrigerators or to cool electric circuits.
- The Thomson effect: This was discovered by Lord Kelvin (then Sir William Thomson) – but already noted by Seebeck – who proved its existence by experiment after demonstrating it theoretically. It is a sort of Peltier effect but between contiguous sections of the same metal bar. The Thomson effect relates to the production – or absorption – of heat caused by passing a current through a section of a conductor where there is a difference in temperature between the ends of the section.
Our latest articles
Come and meet us at the various industrial fairs! Our companies Thermibel and Thermimesure – the French subsidiary of Thermibel – will be present to welcome you with a welcome drink and present our new products and demonstrations of…
Project nr 2
ATEX-compliant temperature sensor for pipe temperatures…
Thermibel celebrates 20 years of collaboration with Beamex! Thermibel is the exclusive distributor of the Beamex brand in Belgium. Please contact us.
Thermocouple type “J” for temperature measurement on moving surfaces. Spring mounting Integrated female connector. Business sector: cement.