In the diagram below, thermoelectric current is being made with two different semi-conductors, a conductor connecting them, and heat. Electrons flow away from the heat in the n-type ("negative") semiconductor and, in effect, toward the heat in the p-type ("positive"). When something like a radio is fixed to the ends of the semiconductors, current flows through it and, hence, powers it.

The direct conversion of heat into an electric current is demonstrated below as the heat from a candle, acting through a thermocouple, produces more than two amperes of current.
[the demonstration is from 1959]

Thermoelectric generators are not very efficient for large-scale use, but they are ideal for powering satellites (usually with a radioactive heat source) and for the powering of small appliances (radios, for example) in areas where "traditional" electric generation is unavailable.

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This page was last updated on 08/17/2018.