Common Mode voltage

Discussion in 'The Projects Forum' started by ectmlk, May 17, 2009.

  1. ectmlk

    Thread Starter Member

    Feb 11, 2008
    21
    0
    Hey
    I've been trying to graspe common-mode voltage (op-ampS), but i ahven't found a decent explanation of it, probably because it is such a simple term it doesn't require much explaining. However i would like an explanation that helps when dealing with real world problems, for example noisey grounds, isolated grounds, op-amp input-offset specs, its relation to differential voltage that is amplified.
    I would appreciate it if some had a few ideas on this.

    If i tie the two inputs together and assume the input offset is ideal (0), will the output be zero
    if the ground rail powering the op-amp is noisey?

    Thanks
     
    Last edited: May 17, 2009
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Check out the material in the AAC ebook on the topic of common-mode as it relates to opamps.

    hgmjr
     
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