Input Tracking Property of an Op-Amp

Discussion in 'Homework Help' started by amjg92, Jan 4, 2012.

  1. amjg92

    Thread Starter New Member

    Dec 14, 2010
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    Hi, I need help to understand what is the Input Tracking Property of an Op-Amp, and the conditions under which it applies. I seem not to be able to find anything on the web about it. All I can understand is that it has something to do with the difference in voltage between the input terminals. Am I totally off the track?
    Thanks
     
  2. justtrying

    Active Member

    Mar 9, 2011
    329
    351
    I am not sure what you are referring to...

    in presence of negative feedback, input at two pins is the same as they are (for analysis purposes) seen as shorted together. This means that voltage difference between two input terminals must remain 0V. Whatever voltage is applied at one input is seen at another.

    http://www.allaboutcircuits.com/vol_3/chpt_8/4.html
     
    Last edited: Jan 4, 2012
  3. amjg92

    Thread Starter New Member

    Dec 14, 2010
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    0
    I have found out that the tracking property only exists if there is a feedback loop and the op-amp is not in saturation. As vp - Vn = Vd the difference in voltage between the terminals.
    but I need a derivation of this property
     
  4. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    Perhaps you are thinking of an op amp configured as a voltage follower.
     
  5. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
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    An op amp will output whatever voltage it takes, within supply limits, to keep the voltage at the + and - terminals equal.

    This applies to amplifiers, followers, inverters, etc.
     
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