[sdiy] capacitor ID

[Tony Clark]

> >    Definately a tantalum (read _EVIL_!) 1uF 35V.  Use Electrolytic in
> > stead if you really want to save yourself some future headaches!
> 
> what's bad about them? quality? tolerance?

   Well of all the capacitors I've used, tantalums seem to be the worst.  
They all have this wierd ability to spontaneously short out for no 
apparent reason.  Sure other caps aren't without their faults, but most 
only go out of spec after a time, which is why we have the wonderful term 
"recapping".

> >    Looks like tantalums again, so it's just like the first set, 1uF.
> > Again, you might want to find something else to replace these with.
> > More than likely these are doing nothing more than filtering the supply
> > line to the IC's, so it would do to add a beefier part here anyway (you
> > really don't want these shorting out the power line!).  Again I'd go with
> > electrolytic.
> 
> beefier as in 'different material' or as in 'higher value'?

   Higher value.  Higher voltage ratings aren't necessarily a good idea 
as larger voltage ratings usually mean poorer performance at lower 
voltage levels.  That being said, typically aim for twice the rated 
supply voltage (+/-15V use 35V rated caps).
   Anyway, back to value, 1uF is a little small in my book for a IC filter 
cap.  I'd aim for anything 10uF or higher (I use 47-100uF myself but then 
I'm a nut (according to Harry!)).  However if the supply lines are 
relatively clean, then it probably won't matter much what value you stick 
there!
   Again, this is going under the assumption that those are being used as 
supply filters.  :)

   Cheers,

   Tony

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