5 Feb
2015
5 Feb
'15
11:36 a.m.
It really depends on each individual scope and it's worth checking the
manual or spec sheet to be 100% sure of what it can or cannot do; this
could be particularly worthwhile if you have a scope that was sold more
into the field service market... My Tek 222, for example is
double-insulated with fully isolated channels and is designed to be able to
safely float up to 400 V p-t-p. The 222PS or 224 will withstand higher
yet...
Best,
Sean
On Thu, Feb 5, 2015 at 2:20 PM, Mouse <mouse at rodents-montreal.org> wrote:
That amounts to a differential (rather than single-ended) input, and I
would consider that the _right_ way to do it. But, of course, that
costs, and single-ended is plenty good enough for most purposes, so
that's what most scopes do. :-(
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With most 'scopes one side of the input is
grounded [...]
Ah. That's the part I was missing! I (naively :-) assumed that
the
'scope's whole input amplifier would be 'floating', and the input
signal would be taken as referenced to the 'ground' on the probe,
which could itself be floating.