Re: gEDA-user: buzzing board

["Steven Michalske" <smichalske@xxxxxxxxx>]

to reduce the peaks even more you mau double up your tants if that is
possable with your parts/layout.

:-)

Sorry i never got to doing the math with your curents and voltages....
 work crept up on me and sent me to china......   Hellos to all from
Shanghai.

On 9/28/07, DJ Delorie <dj@xxxxxxxxxxx> wrote:
>
> I got the new parts today.
>
> Redux:
>
> Adding 100uF electrolytic, swapping in 10u 25v 1206 ceramic did NOT
> get rid of the buzzing, just reduced it a little.
>
> Swapping in 10u 16v 1206 tantalum with the 100u DID get rid of the
> buzzing, both the low pitch and high.
>
> There's still 80mV P-P spikes on the line[*] at 8.3KHz (line refresh
> rate) but that's 6X better than the 500mV ripple it used to have.
>
> Lesson: for heavy-noisy loads at audible frequencies, you need
> sufficient non-ceramic decoupling before (or instead of) the ceramics.
>
>
> [*] http://www.delorie.com/electronics/alarmclock/
>
>
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>


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