Jeez, strike my last response, I replied before reading all the details.
You measured the AC Line voltage with the scope, and that made a spark?

On Wed, 13 Feb 2002, Rodrigo Valladares P. wrote:

> Hi all,
>
> After reading the benefit of an oscilloscope, i took one that is not used in
> my work to debug (is this used in hardware too ?) a pic circuit. I have ZERO
> experience with scopes, so, and i attach the probe to Ch1, the probe has a
> clip, i grip it to gnd and the pin of the probe to what was i really want to
> measure... BUT, i have a 50Hz superimposed over my signal, and showme not
> really what i expect, then measuring the line ac make some spark in the
> probe (the scope can accept 400 vac). Using a tester, and the scope off, i
> discover that the clip is connected to the line ground (0 ohm), and i
> suppose that the test probe was isolated from the main line. I'm wrong and i
> must go to buy "measuring with a scope for newbies" or the scope is bad?, i
> don't have none to ask in my work, because is not used and is there only by
> a mistake

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