Talk:Test probe

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[edit] x1/x10 probes - why?

Lots of passive scope probes have a x1/x10 switch. In all my years of engineering work, I have never switched one of these probes to x1. The only reason I can think of for having this switch is in case your scope doesn't have a x10 probe setting, but then I've never seen such a scope. Is there any technical reason why you would ever want to use a probe in x1 mode? --Heron 16:14, 26 July 2006 (UTC)

I never have either. As for the scope, I thought that's what the extra pin was that makes contact when you connect the scope (the gold ring around the socket) - if you insulate that, the scope doesn't know it is a 10x scope. My only hypothesis is extremely low voltage signals - but then you don't use a standard probe. For example, when I had to do some super low voltage at 1x, I used a cable that went from SMA right to the scope... — RevRagnarok Talk Contrib 16:49, 26 July 2006 (UTC)
When all the gain you had was 50 mV/division and you were trying to look at low-level signals, you bet you switched your probe to 1X! ;-) It's a lot less of an issue nowadays where ranges such as 1, 2, or 5 mV/division are common.
By the way, on most Tek scopes, "that ring" isn't just binary. Certain values of resistors between BNC ground and that ring will also cue a 100x attenuation factor. Nowadays, of course, TekProbe and whatever they call the newest probe interface have far more capability, with the 'scopes routinely displaying things like probe model numbers and serial numbers.
Atlant 18:04, 26 July 2006 (UTC)

[edit] Z0 probes

Heron just switched the Z0 discussion into the present tense and, while I'm sure these probes are still used and I agree with those edits, they lead me to wonder: Are new Z0 probes still being sold by anyone? They're certainly obsolete; I was looking at the specs on one of our FET probes and in every area except dynamic range, it blows the Z0 probes away:

Tek P7240:
  • <120 ps tr
  • 4.0 GHz bandwidth
  • 0.85 pF
  • 20 KΩ
  • +/- 2V dynamic range and
  • +/- 5V dc offset, so
  • +/- 7V working range
  • 30 V peak absolute max

Again, except for the price (probably) and the fact that the Z0 could withstand ac signals of about 15 volts RMS or so, the FET probe wins hands down. And the particular one I cited is wonderfully miniaturized with an integrated ground foot.

Atlant 12:29, 8 December 2006 (UTC)

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