Thermoelectric Effect
The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa via a thermocouple. A thermoelectric device creates voltage when there is a different temperature on each side. Conversely, when a voltage is applied to it, heat is transferred from one side to the other, creating a temperature difference. At the atomic scale, an applied temperature gradient causes charge carriers in the material to diffuse from the hot side to the cold side.
This effect can be used to generate electricity, measure temperature or change the temperature of objects. Because the direction of heating and cooling is determined by the polarity of the applied voltage, thermoelectric devices can be used as temperature controllers.
The term "thermoelectric effect" encompasses three separately identified effects: the Seebeck effect (creating a voltage from temperature difference), Peltier effect (driving heat flow with an electric current), and Thomson effect (reversible heating or cooling within a conductor when there is both an electric current and a temperature gradient). The Seebeck and Peltier effects are different manifestations of the same physical process; textbooks may refer to this process as the Peltier–Seebeck effect (the separation derives from the independent discoveries by French physicist Jean Charles Athanase Peltier and Baltic German physicist Thomas Johann Seebeck). The Thomson effect is an extension of the Peltier–Seebeck model and is credited to Lord Kelvin.
Joule heating, the heat that is generated whenever a current is passed through a resistive material, is related, though it is not generally termed a thermoelectric effect. The Peltier–Seebeck and Thomson effects are thermodynamically reversible, whereas Joule heating is not.
Seebeck Effect
The Seebeck effect is the conversion of heat directly into electricity at the junction of different types of wire. Originally discovered in 1794 by Italian scientist Alessandro Volta, it is named after the Baltic German physicist Thomas Johann Seebeck, who in 1821 independently rediscovered it. It was observed that a compass needle would be deflected by a closed loop formed by two different metals joined in two places, with a temperature difference between the joints. This was because the electron energy levels in each metal shifted differently and a potential difference between the junctions created an electrical current and therefore a magnetic field around the wires. Seebeck did not recognize that there was an electric current involved, so he called the phenomenon "thermomagnetic effect". Danish physicist Hans Christian Ørsted rectified the oversight and coined the term "thermoelectricity".
Peltier Effect
The Peltier effect is the presence of heating or cooling at an electrified junction of two different conductors and is named after French physicist Jean Charles Athanase Peltier, who discovered it in 1834. When a current is made to flow through a junction between two conductors, A and B, heat may be generated or removed at the junction.
Thomson Effect
In different materials, the Seebeck coefficient is not constant in temperature, and so a spatial gradient in temperature can result in a gradient in the Seebeck coefficient. If a current is driven through this gradient, then a continuous version of the Peltier effect will occur. This Thomson effect was predicted and subsequently observed in 1851 by Lord Kelvin (William Thomson). It describes the heating or cooling of a current-carrying conductor with a temperature gradient.
See Also
Aharonov-Bohm Effect
Bjerknes Effect
Casimir Effect
Cause and Its Effects
cold center
cold cube of space
Cold Fusion
Cold light
cold multiplies electric potential
cold multiplies memory
cold of space
cold space
Cold
effect of motion
Effect
effects of motion
electric effect
electrical effect
HEAT - Snell
heat death
heat divides electric potential
heat engine
HEAT FROM VIBRATION
heat life
heat multiplication
heat of resistance to tension
Heat pump and refrigeration cycle
heat resistance
Heat
Hundredth Monkey Effect
Kervran Effect
latent heat
law of cause and effect
Law of Heat
Mind Force - a Reproducible Effect
multiplication of heat
Nocebo Effect
Ozone Effects
photoelectric effect
Placebo Effect
production of the opposite effect
Radiant heat
Renner-Teller Effect
ripple effect
solar heat
specific heat
spinning effect
Steric Effects
Table 13.03 - Photoelectric Effect of Elements
Table of Cause and Effect Dualities
thermoelectricity
triboelectric effect
two-way divided effects of motion
two-way effect
Tyndall Effect
WHAT IS HEAT
Zeeman effect
zero cause and dual effect
11.08 - Matter is an Effect of Will Force
14.11 - Ranges of Forces Effects and Actions
14.30 - Effect of Preponderance
15.24 - Water is Sensitive to Biometeorological Effects
16.11 - Seebeck Effect
2.22 - Voiding - an Effect of Desire and Will Force