I'll answer your questions one by one ok..
QUOTE(ableze_joepardy @ Jan 25 2008, 02:38 AM)
or is that ok if some part of the pelt got contact with the heatsink? coz i might consider this
or do i need to attach a copper plate 1st then attach the heatsink? means (heatsink)-(copper plate)-(pelt)
the pelt itself need what to work?
this thing itself already can work isnt? n need those copper plate to increase the efficiency rite?
and again sorry for asking this.. what is cold plate actually?
If the pelt isn't covered completely on both sides by a good conductor, it won't work at maximum efficiency. This is because unlike CPUs, heat is evenly absorbed over the entire surface instead of concentrated towards the centre. So if you cover only 80% of the area, you will only get around 80% efficiency. Same goes for the hot side where all the heat from the cold side is dumped. One way to work around this problem is to use a heat conducting plate to spread heat evenly across the surface (aka hot/cold plate). You can use any aluminium or copper plate for this, preferably around 1-2mm in thickness. Reason for this is like allngap said, the ceramic plates sandwiching the pelter are not really good conductors, anyway they're too thin to evenly spread heat.
Note-I've used the term 'spread heat' here to mean spread heat from a small heat source to the cold side, and on the hot side to allow heat to be transferred to a small heatsink contact surface.
QUOTE(ableze_joepardy @ Jan 25 2008, 05:14 PM)
ive read the tutorial by amok n he use kind of
one of the seller here told me that he's not selling the cold plate.. so how? is that thing seperable? i thot the white square one act as heater on one side and cooler on another?
1) still dont know yet have to study the design 1st.. maybe 80W - 100W
2) im actually doing proj for FYP.. wanna design cool air supplier for cooling purpose.. so basically no conduction.. only use air flow..
btw please enlighten me if u see im sesat or what k.. coz really new to this thing.. means in technical..
No, do not seperate the peltier plates, you'll most likely wreck the pelt. One side is the cold side, which absorbs heat roughly about the amount rated (eg 80W, in practice its somewhat lower). The other side is where the heat is dumped, keep in mind the peltier also produces heat on its own, so usually the ammount of heat coming out from the cold side is double of that absorbed on the hot side. Also keep in mind that some of the heat from the hot side will leak over to the cold side-the peltier itself is a forced heat transfer device but not a good insulator, so temps will be slightly higher than calculated.
If you accidentally reverse the voltage, don't worry. It still works, but hot side and cold side are now swapped. If you don't know which side is which, just connect the peltier to a 9v batt and feel which side is the cold side. a 9v batt can't supply enough current to allow a pelt to overheat (it'll run flat in minutes, even the voltage drops like a rock in just seconds), but it can supply enough for a few seconds that you can feel which side is the cold side.