Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "sbdwag" <sbdwag@...> wrote:
>
> Len
> 
> I am really just a grasshopper but the power supply circuit filters
> well and is very stable.
> 
> http://www.wagsterstuff.com/photos/pssch.jpg
> http://www.wagsterstuff.com/photos/pspeg.jpg

A point you might keep in mind is that big electrolytic capacitors
have quite a bit of internal inductance, so it isn't so important that
they have very little trace length between them and something that
needs to be close to capacitance.  Getting them close won't help, much.  

But the regulators have best stability when the three small capacitors
connected to them all hit ground at the same node, and when there is
very low trace inductance between them and the regulator.  So the .22,
10 and 1 uf caps should be tucked in as close to the regulators as you
can fit them, with all three sharing a very short ground branch.  

Since the big electrolytics can be further away and still work fine,
and since they are temperature sensitive and they generate internal
heat from ripple current, and the regulators get hot, it is a good
idea to have them located a fair distance from the regulators, and
with a bit of air space all around to keep them cool.