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cheap aluminium for cooling transistors and such? Answered

i just saw an aluminium stair (costing bout €30~€40) and wondered why i couldnt cut it up, and use it to create a heatsink for transistors and stuff like that.

would this make any difference with comercial heatsinks?
only in terms of heat-conduction
i know shape is a factor, but i'd like not to get into that, i could bend the cut-up stair or something

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steveastroukBest Answer (author)2010-05-07

Depends just how much heat you are expecting to dump, shape makes a heck of a difference !

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godofal (author)steveastrouk2010-05-07

i know that, i was just wondering if the heat conduction is the same.

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steveastrouk (author)godofal2010-05-07

The thermal conductivity of the metal will be the same.

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rickharris (author)2010-05-07

In general no reason not to at all.

The main aim is to provide a good surface contact with the transistors to be cooled and as much surface area for cooling as you need (want - have to have!)

IF the situation is critical and a LOT of heat is generated (I would review your circuit design in that case) then a commercial heat sink will give a bigger heat transfer than anything you will make (more than likely) but for most uses just any metal (copper, aluminium, brass) will suffice if there is a good heat transfer from transistor to heat sink to air.

Fan cooling helps as well.

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godofal (author)rickharris2010-05-07

i wasnt designing anything, i just saw that alumium stair, and thought it might work, cheaply :D

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NachoMahma (author)2010-05-07

.  As steveastrouk hints at there's more than one variable involved. The biggest factor is how much heat you need to dissipate. For low-wattage applications, just about anything that will pipe a little heat away from the component will work. Just make sure you supply plenty of air circulation around the sink (which is often enhanced by the sink's shape).
.  Ie, your Al stairs will probably make good heat sinks for low power parts but maybe not so good with higher power components.
.
.  BTW, it's not uncommon for Al alloys to be too brittle to bend very far without breaking.

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