RE: differential probes

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

Hi Jimmy,

At 08:55 PM 7/15/2003 -0700, you wrote:
>Hello,
>
>Why would there be two separate MOV (or spark gap)
>grounds? It seems like having the grounds floating
>would just allow bigger spikes through. It seems like
>you would want it at the same voltage as the low
>voltage ground, but not directly tied, in case the
>MOVs see some high voltage.

I am thinking "ahead" toward stacked or totem pole IGBTs...  Bwahahaha!! ;-)))


>There is still the problem of getting the probes
>connected to the board. Maybe I could get some high
>voltage BNC connectors, or grind the most of the pins
>off, and cut the board.

Note that high voltage BNC connectors are about $35 "each"...



>How bad of a "nightmare" would it be to add some more
>resistance at the end? I would only be measuring a low
>frequency sinewave, and I don't care too much about
>the accuracy. I would just want to make sure it wasn't
>clipping, so I could prevent my IGBTs from exploding
>again.

At <1MHz things get easy.  "I" am thinking far higher frequency where 
things get real goofy....  But maybe this is all not a concern to "your" 
needs...

Cheers,

         Terry