Op-Amp output

Discussion in 'Homework Help' started by Agonche, Jun 19, 2013.

  1. Agonche

    Thread Starter Member

    Aug 26, 2011
    30
    0
    I am preparing for an exam and solving random problems.
    I'm not sure if I solved this one correctly so I just need a confirmation.

    Find the output expression:

    [​IMG]

    This is a Differential amplifier, right?
     
  2. LvW

    Active Member

    Jun 13, 2013
    674
    100
    Hi Agonche,
    the result is correct - you have applied the superposition theorem.
    Yes - it is a diff. amplifier.
    For
    R2/R1=R4/R3=1
    you simply have the difference Vout=V2-V1
     
  3. WBahn

    Moderator

    Mar 31, 2012
    17,720
    4,788
    Some might call it a differential amplifier, but I wouldn't. A differential amplifier amplifies the difference of two signals, so you need to have something of the form:

    Vo = A(V1-V2)

    Which you don't have.

    I would say that this is an amplifier that produces the weighted sum of two inputs with the two weights being oppositive in sign. If you adjust things so that the magnitude of the weights is equal, then it becomes a differential amplifier.

    But, as I said, others aren't as picky about such things as I am.
     
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