Subject: Re: Potentially stupid question about AC
From: the.cat.in.the.hat@usa.net
Newsgroups: comp.sys.apple2
References: <19990820022946.21502.00001367@ng-ba1.aol.com>
X-Newsreader: Lotus Notes Release 5.0 (Intl) 30 March 1999
X-Priority: 3 (Normal)
X-MIMETrack: Serialize by Notes Client on Cris Koch(Release 5.0 (Intl)|30 March 1999) at
 20/08/99 05:34:25 PM,
	Serialize complete at 20/08/99 05:34:25 PM
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Organization: Internet Primus
Message-ID: <935134436.957343@diddley.primus.com.au>
Cache-Post-Path: diddley.primus.com.au!unknown@srac110-071.ports.primus.com.au
X-Cache: nntpcache 2.3.3 (see http://www.nntpcache.org/)
Lines: 66
Date: Fri, 20 Aug 1999 07:33:54 GMT
NNTP-Posting-Host: 203.134.0.92
X-Complaints-To: abuse@telstra.net
X-Trace: nsw.nnrp.telstra.net 935134434 203.134.0.92 
(Fri, 20 Aug 1999 17:33:54 EST)
NNTP-Posting-Date: Fri, 20 Aug 1999 17:33:54 EST



>So why is one lead considered "live" and the other
"neutral" if they seem for all intents and purposes
to be the same.  You can plug something in
backward and it'll still work.  Also, why does the
electricity go into the ground if it leaks from a
grounded device?  Does the earth and the power
station form a circuit or something?

The reason why you can plug in something backwards and it will still work 
is as follows:

Because the waveform oscillates, that is, positive voltage decreasing to 
negative voltage and vice versa, there is really no definite positive or 
negative. And since the regulators that change AC to DC (no appliance 
except bulbs and heaters can run on AC (and see below*)), don't depend on 
a positive or negative, you can plug something in backwards and it will 
still run

The reason why one lead is considered live and the other neutral is as 
follows:

As before, there is no positive or negative. Look at this diagram (or 
convert to Courier or monospaced font if it looks wrong

-----LIVE-----+   +-----NEUTRAL----
             l|   |n
             ---------
            |APPLIANCE|
             ---------

Connected properly, it would work fine. The circuit is completed. Voltage 
is running to the appliance and is running out of it just fine.

Consider this
-----LIVE-----+   +-----NEUTRAL-----
               \  /
                 X -live and neutral do not touch
                / \
              l|  |n
              ---------
             |APPLIANCE|
              ---------
Since there is no definitive positive and negative for AC, the thing still 
runs. The circut is completed. Voltage is running to the appliance and is 
running out of it just fine.

Also possibly it is just to define which pin on your plug is which, but 
more likely, it is the voltage straight from the supply, which current has 
not been subtracted from, the pure 15A 240V (your area may differ) from 
your supply.

The reason why electricity flows to ground is as follows:

Like lightning, electricity always tries to find the easiest path to 
ground as possible. One of Nature's law is to always maintain an 
equilibrium. Electricity is the stuff that tries to make an equilibrium 
between + and -.  If a short is in a household circuit, say, at the plug, 
the easiest way to ground is through the ground pin. This is a safety 
measure for faulty plugs.

I hope this has not been to technical and you can understand this. Please 
let me know.


I am only 14 but have a firm grasp on electricity and physics