Seebeck investigated the thermoelectric properties of a large number of metals and arranged them in a thermoelectric series. When a circuit is formed of two metals in the series, the thermal electromotive force (emf) is greater the further the metals are apart in the series. Also, the direction of the current, at the hot junction, is from the metal occurring earlier in the series to the metal occurring later in it. The following is a selection from Seebeck's series: bismuth (Bi), nickel (Ni), cobalt (Co), palladium (Pd), platinum (Pt), copper (Cu), manganese (Mn), mercury (Hg), lead (Pb), tin (Sn), gold (Au), silver (Ag), zinc (Zn), cadmium (Cd), iron (Fe), antimony (Sb), tellurium (Te). The position of a metal in this series, as Seebeck himself observed, is dependent upon the temperature and also somewhat upon its purity. The thermal emf for the couple Cu and Fe shown in the diagram, although not atypical, is only 1.22 millivolts for t2 - t1 = 100°C.
The Seebeck effect is not independent of, but is rather a combination of, the Peltier and Thomson effects.
Related categories• HEAT AND THERMODYNAMICS
• ELECTRICITY AND MAGNETISM
• SOLID STATE PHYSICS
Source: Duckworth, Henry E. Electricity and Magnetism, pp. 180-181. New York: Holt, Rinehart and Winston (1960).
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