Re: gEDA-user: buzzing board

[Ben Jackson <ben@xxxxxxx>]

On Wed, Sep 19, 2007 at 01:30:33PM -0400, DJ Delorie wrote:
> 
> > The PCB for my alarm clock buzzes.
> 
> If I replace just the +12v cap with a 22u elec, the +7 cap still
> buzzes.  I suspect the elec alone can't react fast enough to get rid
> of the ripple.

Or is it reacting too quickly?  Some power supplies need a minimum ESR
so that the output cap acts as an RC filter.  Your electrolytic cap is
almost certainly higher ESR than what you had in there.  Try air-wiring
in your original cap with 1-5R and see what happens.

-- 
Ben Jackson AD7GD
<ben@xxxxxxx>
http://www.ben.com/


_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user