David VanHorn email (remove spam text)
-----BEGIN PGP SIGNED MESSAGE-----
At 10:53 AM 6/6/00 -0700, Peter Schultz wrote:
>What he is trying to say about a rule of thumb. Common practice is a few
>extra capacitor does not hurt.
>Most of the cases filtering is over done and try to compensate for bad
>layout, grounding systems....
Extra caps will not save a bad layout. It's like bigger engines on the
Occasionally, accidentally, you may hit something that makes the problem
look better by shifting it somewhere else.
>Nice example is a high-end audio preamplifier, takes about 50 ma current
>from the power supply, which was filtered by 22000 uF capacitors....
Great example of bad bypassing.
If these large caps were perfect, then this would be a good idea.
It would be very interesting to sweep them, and see where they are really
acting as low impedance capacitors. I suspect they are very effective at
60-120 hz, (of course good regulation would do far more to eliminate PS hum
than large caps) but up at 10-40kHz, they may not be any more effective
than maybe 100uF (not sure here, I haven't made the measurement on such
large caps, and it would be pretty specific to type)
Are you an ISP? Tired of spam?
http://www.spamwhack.com A pre-emptive strike against spam!
Where's Dave? http://www.findu.com/cgi-bin/find.cgi?kc6ete-9
-----BEGIN PGP SIGNATURE-----
Version: PGPfreeware 6.5.2 for non-commercial use <http://www.pgp.com>
-----END PGP SIGNATURE-----
In reply to: <A60A7E4FA193D211A6720008C7B131BF03504FA9@nt3.minimed.com>
See also: www.piclist.com/techref/logic/dsps.htm?key=filter
You must be a member of the
piclist mailing list
(not only a www.piclist.com member) to post to the