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Message-ID: | <55998CC5.9020509@sbcglobal.net> |
Date: | Sun, 05 Jul 2015 13:00:05 -0700 |
From: | "Girvin R. Herr (gherr375 AT sbcglobal DOT net) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com> |
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To: | geda-user AT delorie DOT com |
Subject: | Re: [geda-user] OFFTOPIC: New toy... |
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Reply-To: | geda-user AT delorie DOT com |
Peter, Another option I used in the past was to use the scope in differential mode, which is to configure one of the two input channels to be inverted and use two equal probes. The only concern then is to not exceed the scope's common mode voltage. The probe grounds are connected to chassis ground, one probe is connected to the circuit under test common (i.e. neutral) and the other probe is connected to the signal under test. That works fine, but it requires 2 identical probes and a scope that will allow differential configuration. HTH. Girvin Herr On 07/05/2015 07:16 AM, Peter C.J. Clifton wrote: > On 2015-07-03 23:16, Evan Foss (evanfoss AT gmail DOT com) [via > geda-user AT delorie DOT com] wrote: >> Ok. It is odd how many people I know use non-isolated probes on things >> like the 3PH power to the motor. > > My background was power electronics at university, so it seems > obvious.. (likewise, I'm also sure I've accidentally grounded circuits > with an oscilloscope ground probe before now). > > A 100:1 non-isolated probe should be good for probing mains, motors, > but obviously the ground needs to reference a chassis earth, not any > other line (or neutral) conductor. > > Peter > >
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