>Along with all power on that circuit as the breaker pops with extreme
>prejudice, if you're in the US where black is AC hot and green is ground.

hang on, he started off talking about running his PIC circuit from a power
supply, and all he could see on the scope was a massive hum waveform. I
don't recall seeing any PIC chips that run off mains voltage directly, he
definitely talked about a power supply.

I think you will find the power supply has red, black and green terminals on
the front, for positive, negative and ground, with the power supply being
totally floating from ground. Most bench power supplies I have seen are
wired this way.

The reference to mains seems to be a red herring (sic) that has developed
because he talked about trying to measure the mains with the probe. He also
says he has zero experience with scopes, so it would seem this was a
dangerous blunder of the inexperienced. I have not seen anyone else try and
get him back on the right track of debugging his pic circuit with a scope.

Original mail below with emphasis by me.

>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

Now looking at the bits I have underlined, does this not make sense for an
ungrounded circuit behaving as a hum aerial ???? Lets get back to the
original problem.

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