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Thevenin's circuit analysis. Multiple voltage sources

  1. Mar 30, 2016 #1
    Hi, i am halfway through one of my assignments and i require some assistance. I do not seek the answer to the assignment just a little boost to my knowledge.

    1. The problem statement, all variables and given/known data

    Basically, if i am calculating the Thevenin's voltage and the resistor i have removed that is in question has a voltage source on the same branch, do i include the 2nd voltage source when finding the Thevenin's voltage or is this negligible because the circuit is not fully connected.at the points looking in. If there were to be another resistor and that branch, the resistance would be on no concern as there would be no current flowing through it.

    2. Relevant equations


    3. The attempt at a solution
    I have simulated the circuit twice on Multisim, one with a voltage source and one without and i obtain different results.
     
  2. jcsd
  3. Mar 30, 2016 #2
  4. Mar 30, 2016 #3
    There is the circuit i am working on and i require the Thevenins voltage from it. i have originally calculated it without using the V2 but i wasnt 100% sure this was the correct method
     
  5. Mar 30, 2016 #4

    gneill

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    Staff: Mentor

    V2 will contribute to the Thevenin voltage. You can set it aside while you find the Thevenin equivalent of the rest of the circuit, then add it back and resolve to a final Thevenin model. It's perfectly acceptable to apply Thevenin step-wise, transforming and absorbing components along the way.

    EDIT: By the way, if you post the component values and your working we can confirm that your methods are sound.
     
  6. Mar 30, 2016 #5
    Okay thankyou,
    so my way of looking at it is, the Thevenins voltage is the volt drop across Z2 and Z4. Then when the final Thev's circuit is created, a single voltage source in series with the Thev's resistance, i can simply connect V2 and the other resistor in question? is this what you mean?
     
  7. Mar 30, 2016 #6

    gneill

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    Staff: Mentor

    I think you've got it. Basically you can do Thevenin in stages, absorbing more of the circuit as you go:
    upload_2016-3-30_10-54-5.png
     
  8. Mar 30, 2016 #7
    Thankyou, sometimes i just cant see the wood for the trees
     
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