On Sunday, October 09, 2011 09:37:58 PM Bruce Klawiter did opine:
> --- On Sun, 10/9/11, gene heskett <ghesk...@wdtv.com> wrote:
> >Now, this is a small clue. And I would read that as meaning that
> >somewhere, it appears the ground connection from the D/A might be
> >sharing a path with some motor current. A ground loop maybe that
> >defeats the intention of the star topology?
> >"star point"
>
> What is the "star point"?
Sorry, I probably should have elaborated on that. Imagine that someplace
in this equipment, you have a long bolt whose head is spot welded to the
frame. This is the only ground point in the system and all other signal
and power supply commons are stacked up on this one bolt, reaching out to
the rest of the circuit with individual wires for each circuit that needs a
ground reference. So it would resemble a star, where the bolt is the
center of the star with the wires leaving it in all directions. No other
ground connections are allowed because that would make a ground loop with
currents flowing around the loop between the two grounds.
The idea of a single point ground is just that, one common ground for the
whole system. However even the use of 'ground' in the sense that it is
connected to an earth ground, is generally not all that important. What is
important is having one, and only one, point in the system where all the
commons come together.
So when you see 'star point' think of this one single long bolt, it is the
'star' point.
Cheers, Gene
--
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-- Corky Siegel
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