M
Mac
"Mac"
Phil said:[snip]** It would be very easy to forget the switch was set to the 50 ohm
position
and connect the input to a source of high voltage. Phut 50 ohm resistor.
Very easy to "phut" some circuit you are probing too.
The scope input can be set to 50-Ohms. The PROBE input cannot.
** Probes that are 1:1 or use clips or plugs on a length of co-ax
certainly can.
Millions of them in use.
Yeah, but I don't hook generic probes up to my 1 GHz scope.
** Do you have any experience with electronics at all ???
Most logic gates can drive 50 Ohms without going phut, at least for a
while. Lots of op-amps can endure indefinite short-circuit to ground, so
50 Ohms won't phase them at all.
Do you have any experience with electronics? ;-)
Connecting arbitrary internal circuit points to ground via 50 ohms is
lethal.
Well, not literally, lethal, most of the time. Besides, all equipment
requires some skill on the part of the operator.
[snip]As for phutting the input termination, I don't know how much power it
takes to do that, but I'm sure it is possible.
What do you expect the 120/240 AC supply might do to a 50 ohm 1/2 watt
load resistor ??
Phil, there is obviously a power limit. I never said there wasn't. But
there is no reason to assume that it is 0.5 Watts. It is also possible
that the 'scope employs some mechanism to protect against overloads.
[snip]
.......... Phil
Just about all modern high-bandwidth scopes have a 50-Ohm option. Do you
seriously not know that? Haven't you seen a nice modern scope with a
50-Ohm termination option?
If you don't like it don't buy one. But for what I do, it is very useful,
and I doubt I am the only one who sees it that way.
--Mac