Re: Oscilloscope grounding question...

Jim Thompson <To-Email-Use-The-Envelope-Icon@xxxxxxxxxxxxxxx> wrote in
news:sue414l3sjj7p41irn1ucltaf1aj9lqegn@xxxxxxx:

On Fri, 25 Apr 2008 13:09:06 -0700 (PDT), "J.A. Legris"
<jalegris@xxxxxxxxxxxx> wrote:

On Apr 25, 8:34 am, Jim Yanik <jya...@xxxxxxxxx> wrote:
"Paul Hovnanian P.E." <p...@xxxxxxxxxxxxx> wrote
innews:481170D7.DCC8885C@xxxxxxxxxxxxx:



Phil Allison wrote:

<seegoo...@xxxxxxxxx

Running your mains powered test equipment (ie: scope) though an
isolation transformer would probably be a good idea.

**  They all have one of them inside already   !!!

  YOU  ASININE   FUCKWIT  MORON   !!!

...  Phil

My Tektronix 'scope chassis is tied to the AC supply ground. Since
I'm not always certain of how the unit under test is wired, I
always check voltage differences before connecting it.

You want to isolate the DUT,not the scope.
That way,the scope chassis stays grounded,and you don't get fried if
you or someone else lays their hand on the scope case.

TEK used to print a nice booklet on isolation measurement techniques
and do's and don'ts.I used to include one with every scope I
serviced that had the ground pin removed,after replacing the power
cord[mandatory]. TEK also made some nice isolated probes.


http://www.tek.com/Measurement/App_Notes/Technical_Briefs/tds3000-flo..
.

From '77 to '87 I was using a TEK accessory set of probes that
provided high voltage isolation between DUT and scope, so grounds were
never an issue.

A6902,IIRC.

I could never figure out why they stopped making them.
I wonder if it was a liability matter,or just low sales volume?

I also had a wall-mounted, hit-it-with-your-palm, panic button which
would disconnect ALL power to the lab, if an emergency arose ;-)

...Jim Thompson

Our cal lab had one,in the middle of the room.
(ours left the lights on.)
Some places also had an insulated hook-pole to safely drag a body off a hot
hookup...Yowza!

--
Jim Yanik
jyanik
at
kua.net
.

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