In message <[email protected]>,
dated Mon, 20 May 2013, Bill Owsley <[email protected]> writes:
Dr. Tom Van Doren demonstrates that single point grounding is not
possible above the audio frequencies.
Thus the lower cutoff in the "regulations" of 9 kHz. And that is
really old school...
The 'goodness' of single-point grounding is not a function of frequency
alone. Circuit impedances are also involved, and this makes the issue so
complex that no general rule is possible. Each single point has to be
evaluated to determine the acceptability of the impedance between each
point to be grounded and the single point and the impedances between the
single point and every other single point in the assembly. The latter
control the transfer of voltages or currents from one point to be
grounded and others connected to the same single point, and between
single points. The buzz-word is 'ground bounce' but it's not confined to
digital circuits; ground bounce in analogue circuits is (normally) less
abrupt but still present.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
They took me to a specialist burns unit - and made me learn 'To a haggis'.
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
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