ground clip on oscilloscope

Discussion in 'General Electronics Chat' started by gjo, Oct 28, 2013.

  1. gjo

    Thread Starter New Member

    May 22, 2013
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    What purpose does ground clip serve on oscilloscope connected to isolation transformer
     
  2. crutschow

    Expert

    Mar 14, 2008
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    It provides a return path for the signal being measured by the oscilloscope.
     
  3. WBahn

    Moderator

    Mar 31, 2012
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    Do you mean that you are powering the scope through an isolation transformer, or what you are measuring with the scope is being powered through an isolation transformer, or that there is an isolation transformer between the scope and what you are measuring?
     
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    As far as the ground clip is concerned it doesn't matter. Since a voltage can only exist between two points you need the ground clip for the 2nd point irrespective of it being connected to Earth ground or Pluto.
     
  5. WBahn

    Moderator

    Mar 31, 2012
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    I agree. I should have stated that this question wasn't directly related to the OP's specific query, but rather just to trying to visualize the setup they are talking about.
     
  6. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Without a ground clip, you will be fine if your circuit under test is connected to the same ground reference as your scope. If your scope is isolated and/or if you are testing a circuit that is isolated (battery or isolation transformer powered), then you will get a lot of noise because the ground clip will be an antenna to all emf. Your probe will also be more of an antenna than a probe because it has only one connection to the circuit.
     
  7. crutschow

    Expert

    Mar 14, 2008
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    Not if the signal is high frequency (above about a MHz). Then you need the ground clip connected to the circuit ground close to where the probe is connected. to minimize ringing and distortion of the signal.
     
  8. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    True, true, true. I just keep thinking about hobbyists and 555 timer frequencies on this site.
     
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