Power Supply capacitor physical size

[Adrian Graham]

On 03/09/2016 23:27, "John Robertson" <jrr at flippers.com> wrote:

>>> Similar size - then no problem!  But, some new cap types are
>>> VASTLY smaller than the caps from 40 years ago.
>> Hence my question, I'll stick with the same size but higher voltage.
>> 
>> Cheers!
>> 
> 
> You do have to consider where in the circuit the capacitor is. If this
> is a switching power supply (as I suspect) then if the cap is after the
> switching transformer it MUST be a low ESR, high temp cap - otherwise it
> won't last very long. If this is on the primary side and is simply
> filtering the input rectified AC then ESR is not as big a problem, but
> you need a good physical size if the switching supply puts out a fair
> bit of current due to heating effects of low frequency ripple.
> 
> So, it all depends.
> 
> For general repair I would get the best grade of capacitor - say
> Panasonic - with a nice low ESR and away you go.

Panasonic and Multicomp as it happens, identical capacitance and similar
size but higher voltage rating. The mentioned heating effects worried me so
I went big.

Cheers,

-- 
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
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