User:Rajareddy/Sandbox

thermoelectricity is a one of the subject in physics and it is developed by thomas johann seeback. He was a physicist who in 1821 discoverd the thermoelectric effect.Seebeck Was born in Reval to a german merchant family.he received the medical degree in 1802 from gottingen university .In 1821, he discovered the thermoelectric effect and where a junction of disimilar metals produces an electric current when exposed to a temperature gradient.this is now called the peltier-seeback effect and is basis of themocouples and themopiles. There are many applications of themocouples one is Measurement of temperature and 2)Detection and Measurement of intensity of heat radiation and constant heat .In thermoelectricity, there are three main important effects and they are seeback , thomson effect and peltier effects .now we can explain the three effects in briefly. seeback effect can be example of emf and leads to the voltage and current and in this seeback coeffient can be known as a thermopower.peltier effect can be example of refrigerators and in this mainly thermoelectric cooling takes place.thomson effect can describe the heating or cooling of a current carrying conductor with a temperature gradient. Thermoelectric circuits have been used in small thermoelectric generators to furnish power in remote areas and in space probes for radio transmitters and receivers and other devices that require relatively small amounts of electric power. The thermocouple, an important temperature-measuring device, also uses a thermoelectric circuit. When one of the junctions is at a different temperature than the other, a direct electric current will flow in the circuit. For a given thermoelectric circuit operating in a given temperature range, the magnitude of the current depends mainly on the temperature difference between the two junction—in general, the greater the temperature difference, the larger the current. when two different metals are placed in contact, their electron gases diffuse into one another. Because of the different densities of the electron gases and because electrons carry an electrical charge, the metals at the junction become oppositely charged. This difference in charge produces a potential difference across the junction. The extent of diffusion of the "electron gases" depends on the temperature. If the two junctions are at different temperatures, a potential difference will exist between the junctions and a current will flow.