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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


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

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

The thermal conductivity of the metal will be the same.

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.

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

.  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.