Thermoelectric Coolers
(TEC or Peltiers)

Simple test to make sure your TEC works

The most simple test is to measure the electrical resistance of the TEC. However, you would need to make a AC resistance measurement either by using a digital impedance meter or LCR. You cannot use a standard ohm meter with a dc input signal because you will not get accurate readings due to the fact of varying temperatures.

Performance Vs Power

Input power can be I (current) V (voltage) or IV (the product of current and voltage)

The above graph shows the graph of Input power Vs performance. Basically what this says is that most the TEC's are operated somewhere between 40% to 80% of Input Power MAX. Basically this is a sweet spot of operation.

The Theory of the Seeback effect.

The Seebeck effect is described as the "creation" of a current when 2 different conducting materials are joined in a loop such that the two junctions are maintained at different temperatures. When you have two different materials you may assume that their respective free electron densities are different while they're both at the same temperature. A temperature difference merely gives the free electrons more kinetic energy to move around in. When you join the two materials the more energetic electrons from one material will migrate over to the other material in an attempt to establish a new equilibrium of the junction and balance out the charge difference. Naturally, this disturbs each of the two materials own individual equilibriums (that is, their equilibrium states before they were joined together). The disturbance as mentioned previously is caused by the migration of energetic free electrons which as a result leaves exposed positive charges on one side and an excess of negative charges on the other from the point of view of each material. As we've seen before, this causes an electric field to be formed across the junctions. Since the temperature determines how much more energetic the free electrons will be and their migration determines how many exposed positive and excess negative charges are on the two sides of the junction, it follows that the magnitude of the electric field is a function of the temperature. Since the setup of the two materials is in a loop, a current forms from the electric field and circulates the loop. At one junction where the electric field "goes along" with the direction of the generated current, the current has "an easy time" but at the other junction, the current must go against the electric field.

Please note that we haven't covered the design system notes of the heatsink and peltier. That's for another article.

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