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Questions about TEC(Peltier) component

R

razeman

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Hello, I have the following questions about a TEC Module (Peltier Module), hope you can help me with them:

1) I've read that this modules are current dependent, but I've also read they are somehow voltage dependent, which one is correct? If I want to get more temperature delta between the sides, should I rise the current in the module?

2) I'm also informed that it's very viable to use a PC PSU in conjunction with the modules and the laser, the problem is that when I connect it (I know for sure that the PSU is completely functional) and test it with the multimeter for voltage or current I have no reading.
May I be measuring erroneously? How can I make it work?

Thank You
 





E

ElektroFreak

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Well, you need voltage to have current, so any electronic component is dependent on both. TECs are more current dependent than voltage dependent. A 12V TEC will still cool the same amount with less voltage and more current. Say to keep a heat producing component at 25C you need 12V at 1A. You could also keep the same component at 25C using 6V at 2A.

If you're not getting any voltage readings with the PSU powered up and your probes on the right terminals then either your PSU or your multimeter is broken. With current, you won't measure any reading unless you break a circuit with current running through it and insert the meter in series. you could also use a clamp-on type current meter to read current without breaking the circuit. If there is no circuit drawing current, then there is no current, only voltage.
 
charliebruce

charliebruce

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If you want to power up the power supply, there are several guides - but it's as simple as tying one of the wires in the 20/24-pin bundle to Earth (IIRC, it's the green one near the center of the bundle). This can be done with a paperclip, and there are several guides online. Use google and you will be rewarded. Make sure you do so with a load, however, I almost blew a power supply by starting it with no load (though the smoke cloud was pretty spectacular, it still started afterwards).

When you've done this, the yellow is +12v, any black wire is 0v. You'd be best off using one of the Molex connectors (4-pin, Plastic elongated D-shaped connectors).
 
N

nikokapo

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I answered those questions on a thread from last week. I also included a very good FAQ from another forum, I can't find it though, maybe you can ;)
 
chipdouglas

chipdouglas

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with info i learned here i used my atx @12vdc and put just a 2.2 ohm 2 watt resistor in line. i beleive it is around 600 ma. i left it running for 2 days straight and it still works great. it had 2 inch thick layer of ice (i licked it, i couldn't resist).
 
chipdouglas

chipdouglas

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tell me you wouldn't have done the same (please tell, so i don't feel like a loser) LoL
 
MISTERWILLING

MISTERWILLING

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Does anyone know of a cheap TEC cooler controller? I found some schematics on Sam's Laser Faq's but building them is over my head. I want to maintain a constant temperature with my TEC's so I don't over cool them. I'm going to be cooling some blu-ray diodes and going too cold will cause a drop in visibility. I am also going to be cooling a ~635nm diode and I would like to keep it as cool as possible(without going to far and causing condensation build up) because that will increase its visibility. I have done a bit of searching and I am going to continue to search but I wanted to see if anyone knew off of the top of their head.
 
R

razeman

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@MISTEREWILLING:

As far as I know you can keep a constant temperature by having a constant current, that is using a LM-chipset family circuit, like the one from the lasers.
 
E

ElektroFreak

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Yep. An LM317 driver will work great. Just set it up for ~500mA, start tuning at 0mA and work your way up until you get to where you want to be..
 
MISTERWILLING

MISTERWILLING

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I will try this, I'm going to have the lasers in an analog modulated scanner so I was afraid with laser varying in heat output that I would have trouble maintaining a constant temp.
 
E

ElektroFreak

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You shouldn't need to be too precise.. What you do is tune the TEC over a period of time that allows the diode to warm up to where you want it. Once you got the TEC tuned to this maximum temperature, it should stay that way. It will take the system a little bit to get to this point, but all lab lasers have a published warm-up time. Yours would be no different than that.
 
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