From: "Brill Pappin"
Subject: Re: Ground loops?
X-Newsreader: Microsoft Outlook Express 6.00.2600.0000
Date: Sat, 14 Sep 2002 22:20:57 GMT
NNTP-Posting-Date: Sat, 14 Sep 2002 18:20:57 EDT
This has got me thinking about noise as well... in my system , the boards
are all connected in series... I had planned to have a single ground line on
the ribbon cable between each board, but I wasn't taking the ground loops
In just about all cases here, any loops I generate will be on the boards
themselves, however, with the ground between boards acting as a power
I expect the ribbon cable to be up to a foot long maximum, and most will be
What do I have to worry about in this situation?
- Brill Pappin
"James Meyer" wrote in message
> On Fri, 13 Sep 2002 15:53:58 +0100, "markp"
> >Say I had three printed circuit boards. Each board requires a +5V supply
> >ground, and in addition the boards are inter-connected via ribbon cables
> >using separate cables. Let's say the environment is a little noisy from
> >electrical point of view, so the ribbon cables use the every second
> >conductor is grounded type construction.
> >First, what is the best way to connect power? My instinctive reation to
> >is star ground where each card's ground goes to a common point. Similarly
> >for the +5V.
> >Second, should the grounds on the ribbon cable connectors be grounded on
> >both ends? Again my reaction is grounding at both ends creates ground
> >that could pick up noise from the environment. My feeling is that only
> >end of the connectors chould be grounded and the other ends left
> >Any views?
> If only one board has any I/O connections to the "real world", then I'd
> pick that board as the "star" point and feed the two other boards with
> grounds, and Vcc through the ribbon cables. The "star" board would be the
> one connected directly to the power supply(s).