[sdiy] yard sale find

[Theo]

From: harry <harrybissell at prodigy.net>

> Theo wrote:
>
> (and is gonna get a butt-kick for  ;^)
>
> > <sni> As long you don't work with high voltages you don't need a 10x
probe.
>
> Arrgh. BIGGEST mistake you can make.  The purpose of the 10X probe is
> almost NEVER to allow "higher voltages"...  its to allow the probe to load
the
> circuit with 10X the resistance (1/10 of the load).
>
Ouch.., but thanks anyway.
My old banana jack input  Heatkit scope never had a real probe, let alone a
10x one.
It did no better than 0.1V/div, but then the _internal_ noise got visible.
Guess I picked up some pretty bad habits because of this old beast.
Got a real scope now, but never changed the way I worked.
I now see on the specs of my probes the 10x mode also gives better band
with.

Now that I have already proven my stupidity, I may as well go on and ask a
stupid question.
Using FET inputs one can get extremely high input impedances,
so why use scopes a "low" input impedance of only 1M ohm and not 10M or
100M?

Theo
(walking around, cause sitting down hurts too much)