Hi PN,
Well, .. what you need is a way to turn the peltier off when it gets cool enough.. but I have used a Constant Current source before but as soon as the ambient temp changes lower ..so does the peltier.
But for just experimenting you could just use a resistor or a variable supply (like a LM338) and you will see.
But you will be relying on the Dt of the peltier , its a constant. if its say 60 degrees that means when its full on its cooling 60deg below the base temp.
If the base temp gets hot so will the device you cooling so you have a thermal run-away condition. Thats what it needs to be controlled.
If the peltier goes into run-away it can be damaged.
You could probably get away with a cheap fan control circuit that uses a thermistor and an op-amp and a relay...that may work , I googled a few that look easy to make.. but I dont like full-on full off. but if you used a separate supply , that might not make much difference.
The TEC I made was a derivative of one of these circuits.
Or, You could buy a Wavelength Electronics IC that'l do all of it for you. not cheap but it'l be right. for about 100USD.
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