Question on capacitors

[sirzur]

A general question on capacitors and placement on PCBs.

If a board design is such that the capacitor is close to the heat sink and therefore susceptible to failure through overheating, what is the disadvantage of running a wire away from the heat sink to another cooler place to mount the capacitor? Would this cause a problem in the circuit.

[Fizzycapola]

Re: Question on capacitors

I would imagine so, though I have little knowledge. I think the longer the wire between the capacitor and the circuit the less effective it becomes, I read each millimeter has a significant effect. It should also act as an antenna for receiving interference.

[i4004]

Re: Question on capacitors

Would this cause a problem in the circuit.

probably not.

wires wouldn't be too long so resistance(and esr) would be almost the same.
put them on the psu inlet and probably even crappiest caps can last much longer.

It should also act as an antenna for receiving interference.

you can shield it.

[starfury1]

Re: Question on capacitors

it would depend on the circuit and use of the cap

layouts are design to minimize stray effects and interactions from components and adjacent circuits.

So in some cases you may get away with it in others you could great problems.

for example if you were to put VRM output caps On an MB on long leads you would be asking for trouble it might work but you may as well of used GP caps.

adding a little or mounting caps on thier side you will probably be ok
but don't go over board run a lead from one side of a case to the other.

Ive had to do things like that in th past and gotten away with.

Thats my opinion anyway

Cheers