Nodal analysis problem

Discussion in 'Homework Help' started by cheypr, Nov 5, 2009.

  1. cheypr

    Thread Starter Active Member

    Oct 13, 2009
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    OK here is the problem: use nodal analysis to find Vo in the circuit at R6. It is supposed to be 7.57v.
     
    Last edited: Nov 5, 2009
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
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    If you will post what you have done so far to solve the problem we can help you get past your snag point.

    hgmjr
     
  3. cheypr

    Thread Starter Active Member

    Oct 13, 2009
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    OK and here is what did. This is the closest I've become. What I'm doing wrong?
     
  4. cheypr

    Thread Starter Active Member

    Oct 13, 2009
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    wow, your fast, jejejejejje
     
  5. cheypr

    Thread Starter Active Member

    Oct 13, 2009
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    this could help. its a solutio to the problem. the solution is so quick that i dont see how they found the answer.
     
  6. The Electrician

    AAC Fanatic!

    Oct 9, 2007
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    I don't see how they get an answer, either. They only have 4 equations, but there are 5 unknowns. The current Is2 doesn't appear in any of their equations, but surely it has an effect on the solution.

    Perhaps they got an answer from a solution book.
     
  7. cheypr

    Thread Starter Active Member

    Oct 13, 2009
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    thanks, any other idea or suggestion in how to solve this exercise.
     
  8. The Electrician

    AAC Fanatic!

    Oct 9, 2007
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    Your equation for SN2 is incorrect.

    You have:

    -(1/1k)Va + 0Vb + (1/1k+1/1k)Vc + (1/1k)Vd = -.002

    You should have:

    -(1/1k)Va + 0Vb + 0Vc + (1/1k+1/1k)Vd + (1/1k)Ve = -.002

    Then your matrix will be:

    Code ( (Unknown Language)):
    1. [ .0025  -.0005 -.001 ]
    2. [ -.0005  .001    0.  ]
    3. [ -.001    0.    .003 ]
    Solving will give you :

    Va = .69565
    Vb = 4.3478
    Ve = 7.5652
     
  9. cheypr

    Thread Starter Active Member

    Oct 13, 2009
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    Thanks a lot. You all are a good help!!
     
  10. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    Just for 'fun' I thought I'd try a different approach .... I know - I should 'get a life'.
     
  11. The Electrician

    AAC Fanatic!

    Oct 9, 2007
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    I don't know what you mean by "v1 = 4.2 A"; it looks like you're saying that v1 = 4.2 amps.

    And when you say "voltage = 33.6", what voltage are you referring to?

    Look at the designators in the .pdf file attached to post #3. Then:

    Va = .69565
    Vb = 4.3478
    Vc = -5.3043
    Vd = -4.43478
    Ve = 7.5652
     
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