Op-Amp node method

Discussion in 'Homework Help' started by ihaveaquestion, May 7, 2009.

  1. ihaveaquestion

    Thread Starter Active Member

    May 1, 2009
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    Circuit is:
    http://img521.imageshack.us/img521/1750/12343p.jpg

    Teacher used superposition to find the answer

    I wanted to try it using the node method

    I have the voltage at the v+ and v- terminals... but having trouble relating that to Vout... I tried figured out the current in the non-inverting portion of the op-amp by doing

    (Vout - Vm) / 3 where Vm is v-, but that got me nowhere
     
  2. steveb

    Senior Member

    Jul 3, 2008
    2,433
    469
    You are starting with a good approach. You have one equation and one unknown (that is "e"). So you can solve for "e" and now you have a simple inverting amplifier with a V+ reference different from ground.
     
  3. ihaveaquestion

    Thread Starter Active Member

    May 1, 2009
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    0
  4. The Electrician

    AAC Fanatic!

    Oct 9, 2007
    2,281
    326
    What answer is required? Vo?

    If so, you haven't finished the problem.

    You need to write another equation involving Vo.
     
  5. ihaveaquestion

    Thread Starter Active Member

    May 1, 2009
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  6. ihaveaquestion

    Thread Starter Active Member

    May 1, 2009
    314
    0
    Yup they wanted an expression for Vo
     
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