The Basic Phenomenon

Date: 2015-10-07; view: 465.

In any uniformly heated pellet of thermoelectric material, positive and negative electrical charges are uniformly distributed, as in Fig. 1; but when heat is applied to one surface, this distribution changes. Al­though the positively charged ions in the crystals remain fixed, the nega­tively charged electrons tend to move to the cooler end. This results in a gradient of electrical charge and a potential difference between the hot and cold ends, which can cause current to flow in an external load. In actual use, thermoelectric devices are arranged in an array of series-con­nected thermocouples whose materials have been so formulated that their voltages are additive. Through stacking of elements in arrays, voltage outputs adequate for power generation can be achieved.