On Thu, 04 Nov 2004 12:25:06 -0500, StephenTetorka@cs.com wrote:
>This radiant discussion on parasitics invites me to ask a question: "where
>does all the 'mish-mash' go to when a chassis ground is employed?"
>
>Signals and voltages that are DC, AC and RF are all permitted to happily
>co-join and intermix - and to be politically correct, regardless of gender
>(positive or negative cycle) - on this conducting element.
>
>The fact that one chassis 'ground' can easily be a potential different from
>another 'ground' is an issue for another occasion.
_________________________________________________________
The simple answer is, the voltage and current at a point (or more
correctly, between two points) is the vector sum of all the signals
present. They don't really "go" anywhere, they just add and subtract
from each other, including phase angles, to give a single net result.
I prefer not to use the word "ground", since it implies something that
may not be present, i.e., a connection to the earth. Instead, the
word "common" is more accurate, meaning a point which is common to all
circuits.
Your last sentence about a potential difference between "grounds" is
worth noting. When the potential difference causes coupling into or
between circuits, you have a "ground loop", something usually to be
avoided.
--
Bill W6WRT
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