----- Original Message -----
From: <llile@SALTONUSA.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, February 17, 2003 12:45 PM
Subject: Re: [EE]: Measuring AC mains with a O-scope.


> No Isolation Trasformer = BOOM! or Yeeoooooow!
>
> Isolation transformer = OK
>
> Hook the isolation transformer to your device under test, not your scope.
> If you hook the isolation transformer to your scope, the scope ground will
> become live when you hook it to your circuit.  I shocked the livin'
> %$&#%&$% out of my boss this way once, he leaned on the scope chassis and
> touched the meter frame of my bench.  Not good for one's long-term
> employment prospects.
>
> Another time I hooked a scope to a TV with one of the mains wires
> connected directly to the chassis.  Two wire cords should be outlawed, but
> the US lags behind everywhere else in this regard.   BOOM! so much for my
> scope ground lead. Also not good for one's long term employment prospects.
>
>
> Expensive differetnial probes are unneccesary IMHO.  I have one I've never
> used.
>
> --Lawrence

> Jinx <joecolquitt@CLEAR.NET.NZ>
> Sent by: pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU>
> 02/16/2003 08:45 PM
>
> > > Does this change the way one could connect O-scope probes ?
>
> > If your scope has internal grounding... it would be blown to hell
>
> I wouldn't even think of measuring mains without an isolating
> transformer. I have a small 150VA one that goes on either the
> scope or the circuit


On scopes that have differential input mode between two channels, what is
the max voltage that can be monitored?  The Vmax of one channel or both
combined (Vmax x 2)?  {slewrate}

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