Learn About Thevenin Theorem and Dependent Source Circuits

Discussion in 'General Electronics Chat' started by grahamed, Oct 9, 2015.

  1. grahamed

    Thread Starter Member

    Jul 23, 2012
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    Hi

    I am not sure where to post this but.....

    The article says that Vth and Rth are 10V66 and 0R888 respectively. I get 9V and 5R33333.

    I could be wrong, I often am, but it seems hard to produce 0R888 out of 6, 8 and 10. It would seem that the lowest possible resistance, by any arrangement would be 6//8//10 = 2R66

    Plot shows circuit loaded by my value of 5R33 and output being 4V5, unloaded output (Vth) is 9V. I dare say someone will point out my error.


    ACC with R4.jpg
     
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
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    If RL is R4 then
    Rth = (10Ω+6Ω)||8Ω = 16/3 = 5.33Ω and Vth = 12V*(8Ω)/(10Ω + 6Ω + 8Ω) + (1.5A*10Ω/(6Ω+8Ω+10Ω))*8Ω = 9V
    Also please show as this article.
     
  3. Jony130

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    Feb 17, 2009
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    And where is this dependent source ?? Because this will change everything.
     
  4. grahamed

    Thread Starter Member

    Jul 23, 2012
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  5. grahamed

    Thread Starter Member

    Jul 23, 2012
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    Am I missing the point? Is the dependent source being used solely as a method of analyzing the circuit, or what?
     
  6. Jony130

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    Feb 17, 2009
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    In this example author show as how to find a Vth and Rth when we have a dependent source in our circuit.
    But your circuit do not have any dependent source, I see only two independent source. Do you even know what dependent source is?
     
  7. grahamed

    Thread Starter Member

    Jul 23, 2012
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    Probably not
     
  8. grahamed

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    Jul 23, 2012
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    This article seems to be about how to equate fig 2 to fig 1 and find values for Vth and Rth. No?
     
  9. grahamed

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    Jul 23, 2012
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    Ah is it saying the middle current source is 1.5 x Ix? I thought it said Ix = 1A5. If so Mea culpe.
     
  10. Jony130

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    Feb 17, 2009
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    Yes, but in the example the author used the Current-controlled current source (CCCS). And this current source delivers the current equal to 1.5 times the 6Ω (Ix) resistor current.
     
  11. grahamed

    Thread Starter Member

    Jul 23, 2012
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    Yes definitely my error
     
  12. Jony130

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    Feb 17, 2009
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    Here you have a LTspice file. And notice that Vth = 10.6667
     
  13. grahamed

    Thread Starter Member

    Jul 23, 2012
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    As I said I had definitely misunderstood. Thank you for your help.
     
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