Seebeck noticed that when a loop comprised of two dissimilar materials was heated on one side, an electromagnetic field was created. He actually discovered the EM field directly with a compass! He noted that the strength of the electromagnetic field, and therefore the voltage, is proportional to the temperature difference between the hot and cold sides of the material. The magnitude of the Seebeck coefficient (S) varies with material and temperature of operation.
Peltier discovered that whenever a circuit of two dissimilar materials passes current, heat is absorbed at one end of the junction and released at the other. This is a linearly dependent and thermodynamically reversible process, unlike Joule heating which is irreversible and quadratic in nature mean. This process forms the basis for thermoelectric cooling and temperature control, these are currently the widest applications of thermoelectric devices.
Thermo electric effect
Thermo Electric Effect
By: Ahmed Diaa El Din
What is it ?
The thermoelectric effect is the direct conversion of
temperature differences to electric voltage .
The direction of heat flow can be controlled by
changing polarity of the voltage source.
In the 1820’s Thomas Seebeck (Germany) discovered
that if two metals at different temperatures were
touching you could create an electric current.
Jean Peltier discovered that the opposite was also
true. By sending a current through two metals you
could create differences in temperature.
Seebak Coefficient : S=-∆V/ ∆T
ΔV is the voltage difference.
ΔT is the temperature difference between the hot and cold sides .
The negative sign comes from the negative charge of the electron.
The efficiency by which a material is capable of
generating power (Z)
K thermal Conductivity - σ electrical Conductivity - S seebak coff.
Why does this Effect Occur?
Charge Carrier Diffusion and Phonon Drag