Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!think!harvard!seismo!lll-crg!lll-lcc!qantel!hplabs!hao!noao!terak!doug
From: doug@terak.UUCP (Doug Pardee)
Newsgroups: net.rumor
Subject: Re: Safety - Third wire in A.C.
Message-ID: <1114@terak.UUCP>
Date: Thu, 27-Mar-86 11:32:32 EST
Article-I.D.: terak.1114
Posted: Thu Mar 27 11:32:32 1986
Date-Received: Tue, 1-Apr-86 04:29:47 EST
References: <260@uthub.UUCP> <2051@gondor.UUCP>
Distribution: net
Organization: Calcomp Display Products Division, Scottsdale, AZ, USA
Lines: 16

> 	The scope you are using doesn't have two different isolated
> probe grounds - most scopes don't.  This is inconvenient - it makes
> it a little harder to check relative voltages.  If you're going to do
> something about it though, isolate the probe ground in the scope.

Seems that using a 'scope is something people pick up on their own.  So
not all of the tricks are obvious.

The way to 'scope differentials on the more sophisticated 'scopes is to
set channel B on "inverted" and the display mode on "add".  Then use
probe A on the "high" side and probe B on the "low" side.  And connect
the probe grounds to ground.

This isn't a rumor -- why is it here????  :-)
-- 
Doug Pardee -- CalComp -- {elrond,savax,seismo,decvax,ihnp4}!terak!doug