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From: hes@ecsvax.UUCP (Henry Schaffer)
Newsgroups: net.physics
Subject: Re: freq. spectrum
Message-ID: <1787@ecsvax.UUCP>
Date: Tue, 30-Jul-85 09:25:52 EDT
Article-I.D.: ecsvax.1787
Posted: Tue Jul 30 09:25:52 1985
Date-Received: Fri, 2-Aug-85 00:38:24 EDT
References: <199@stl.UUCP>
Organization: NC State Univ.
Lines: 21


  Another experiment at low (power) frequency.  An electricians
neon tester (a small neon glow lamp, e.g. NE-2 with a series resistor
of about 200 kohms.  note NE-2 is an obsolete but still used number),
has one contact on the hot contact of a power line, and I hold
the other contact while standing on a perfect insulator.  (Wearing
rubber soled shoes and standing on dry wood ought to be a good
approximation.)
  The neon tester bulb will glow faintly (but visibly - unless you
are in sunlight you should be able to see it.)  Some reasonable
number of microamperes are flowing through the neon lamp and ME.
(Full brightness of the lamp takes about 400 microamps.)
  How is this power transmitted from the power line to me to ground.
My theory is that this is capacitative coupling between me and
ground.  Does this count as EM radiation?
  Regardless, this certainly is a mechanism for injecting power line
frequency hum into all sorts of equipment in the home and lab.
  NOTE:  This involves the AC power line which can be hazardous, and
can lead to a lethal accident.  Don't mess with the power line without
competent supervision, unless you are competent.
--henry schaffer  n c state univ