5 Feb
2015
5 Feb
'15
12:44 p.m.
On Feb 5, 2015, at 2:17 PM, tony duell <ard at p850ug1.demon.co.uk> wrote:
Absolutely correct.
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.
Clearly not! (I'll have to look at the manuals/prints for my 'scopes -
Tektronix 465's - to see if they are this way. Anyone happen to know,
offhand?) Thanks!
I am darn sure the Tekky 465 does have the 'ground' of the input amplifier --
the outer of the BNC probe connector -- tied to mains ground (and the metal
chassis/case of the instrument).