NNTP-Posting-Date: Wed, 27 Nov 2002 07:01:20 -0600
From: "Arthur Jernberg"
Subject: Re: What is GND?
Date: Wed, 27 Nov 2002 08:01:24 -0500
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Gnd can refer to either the negative return path, chassis ground, or even a
floating 'ground' within only a particular circuit. The schematic diagram
normally indicates the intention of the designers and manufacturers. The
vertical line with horizontal slashes beneath it [producing a downward
pointing arrow] normally indicates earth ground or negative return to
source. The symbol that shows a horizontal line with short diagonal
'feathers' attached, again heading downward, in normally indicative of 'hot
ground. or isolated return ground', which is electrically insulated from the
chassis and the "earth ground" . I know totally confusing!! Consult the
installation manual. As Ian stated, even if both supplies are sourced from
the same return earth rail you may even find crosstalk interference
dependent on currents, etc. Cheers
wrote in message
> BC wrote:
> > When reading a diagram involving a mobile unit using batteries, is it
> > safe to assume the ground is the negative part of a battery?
> > Also, When combinig to different voltage systems, one 12V and the
> > other 5V, do they need to share grounds?
> Ground is just a name, it generally is a voltage which is taken to be
> a reference voltage for all the others, and to not change.
> It may not even be very constant with regard to the supply rails, and
> may be able to supply little current.
> As to mixing voltages, if the grounds are the 0V return of the power
> then generally you have to watch out for signals from the 5V side not
> fully activating stuff on the 12V side, and signals going the other way
> damaging the 5V side.
> http://inquisitor.i.am/ | mailto:email@example.com | Ian
> What a wonderfull world it is that has girls in it! -- Robert A