Seebeck Effect
In a real system where two wires of different materials are connected together with a temperature difference between the junctions, we have a combination of two Thomson and two Peltier emfs.
The overall emf that develops is given by:
E = (?A - ?B)?T + (šABT1 - šABT2)
The Seebeck coefficient (or thermoelectric power),??, is defined by:
The Seebeck effect is used
- in thermocouples to measure temperature
- in thermopiles to generate electricity, and
- in thermoelectric coolers for liquid free refrigeration.
Typical values of thermocouple emfs are:
Platinum vs 13% Rhodium: 1 mv/100°C
Chromel-Alumel: 4 mv/100°C
Iron-Constantan: 6 mv/100°C