ORIGINAL MESSAGE: (may be snipped)
On Sun, 06 Oct 2013 00:44:46 +0000, Manfred wrote:
>Yes, sure! But if you then connect the scope to a direct-line-powered
>circuit, the scope chassis and knobs STILL will have a dangerous voltage
>on it! That's exactly the same as using an isolation transformer to
>power the scope, or to simply use the scope's internal transformer for
>insulation, and lift its ground. In all three cases the scope's chassis
>will end up connected to the line through the circuit being measured!
REPLY:
I grant you the inverter approach is still dangerous, but not to an
experienced tech. The problem with all the above approaches is there is
still significant capacitance between windings of the isolation transformer
or the scope's power transformer and you are still lightly coupled to the AC
line. With the inverter approach, you have a truly "floating" scope. A few
stray pF maybe, but that's about it.
Essentially a larger version of the Fluke ScopeMeter. :-)
73, Bill W6WRT
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