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Op amp node voltage help

  1. Nov 18, 2005 #1
    Hey, I think I need a little help understanding node voltage analysis with ideal op amps. For the circuit I've attached, at node D, I wrote the equation

    ((1/1000) + (1/1000))Vd - (1/50000)Vc - (1/1000)Ve = 0

    However my prof's equation for node D is:

    ((1/1000) + (1/1000))Vd - (1/1000)Ve = 0

    I don't understand why he didn't include the Vc like I did. I understand that Va = Vc, but you can't just say Va = 0, can you?

    thanks much, sean
     

    Attached Files:

  2. jcsd
  3. Nov 18, 2005 #2

    berkeman

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    Staff: Mentor

    Where do the "1000" numbers come from? Can you label the resistors or show their values? And no, Va will not be zero unless the current source has Iout = 0.
     
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