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How to apply Thevenin and Norton Model

  1. Oct 9, 2013 #1
    Hello guys,
    I'm having some trouble reading two circuits :
    Here they are :

    In the first one I need to Determine the Thevenin then the Norton Equivalent of the circuit.

    For the second one I have to find expressions of the current I1 flowing through the R1 resistor, I2 in R2 and then I which goes through the Motor.

    I only need an idea, or a way to re-draw the circuit differently in order to know what theorem to use : Kennelly, Millman, or just good old Kirchoff law.

    Thank you very much in advance :)
  2. jcsd
  3. Oct 9, 2013 #2


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    Gold Member

    I don't mean to sound unhelpful, but It's hard to imagine a circuit much more simple than fig 1.13 for finding the equivalent circuits. If you can't do that one, you should probably go back to studying the basics of just what the equivalent circuits are and how you get them. Certainly, the circuit does not need to be redrawn as it is already trivial.

    I can't read the labels on the second figure so can't comment on that one.
  4. Oct 9, 2013 #3
    Hello again,

    I'm sorry to barge in but I'm just a beginner and I'm really trying to get a grasp on this.

    Here's a draft of what I did for the first Circuit. You can click on the thumbnail to make it bigger.

    I put in a better drawing for the second circuit, with a motor in the middle.

    Could you please tell me if what I did is good, so far?

    Thanks a lot !
  5. Oct 9, 2013 #4
    I forgot to post the picture :
  6. Oct 10, 2013 #5


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    I have no idea what you are doing but on the first one you are turning a very simple problem into something complex. Again, I urge you to go back to basics and study how it is that you are supposed to get an equivalent circuit. How are you supposed to treat a voltage source when solving for the Thevenin equivalent resistance ?
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