From: "David Jones"
Subject: Re: what is this chassi symbol in the pic for?
X-Newsreader: Microsoft Outlook Express 6.00.2600.0000
NNTP-Posting-Date: Sun, 08 Sep 2002 09:06:59 CDT
Organization: Giganews.Com - Premium News Outsourcing
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
Date: Sun, 08 Sep 2002 14:06:59 GMT
thanks that helped a lot. I've really been having a hard time understanding
schematics. this will probably clear up a lot if not almost everything.
"Robert Baer" wrote in message
> David Jones wrote:
> > I don't understand what the chassi symbol at the bottom of the
> > which is in the file attachment of this post, means. if there are
> > of these chassi symbols, which i've seen before, what does that mean?
> > they all connected? when does electricity flow in that direction?
> > dave
> > [Image]
> This is not common; either a ground symbol is used, or no ground is
> shown (not common).
> The chassis symbol (which was shown) is nominally reserved to show
> components that are directly connected to a metal chassis, which may or
> may not be a common wire for all of the circuitry.
> The ground symbol is normally used as a common wire for all of the
> In either case, current going into this "wire" from one or more
> component will flow out to one or more other components; the net is
> zero, just like any other wire.
> There has been a lot of equipment that used a common wire for ground,
> which was completely insulated from the metal chassis.
> And in some of those, i have seen two capacitors of equal value, each
> one going from one side of the incoming 2-wire power cord to the
> chassis. That configuration was supposed to be a safety feature, and it
> is obviously poor engineering and potentially very dangerous.
> In some other cases, only the power transformer core is connected to
> the chassis, which is connected to the third wire (ground).
> In yet other cases, only the ground lead of the circuitry is connected
> to the case (chassis) at one point, which is connected to the third wire
> (PC computers are an example).
> So one could show this in a schematic with a line from one ground
> symbol to the other.