thevenin equivalent

Discussion in 'Homework Help' started by illidari, Sep 6, 2011.

  1. illidari

    Thread Starter New Member

    Aug 26, 2011
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    I am really lost on how to solve this problem with the current sources in the picture.

    I have found the thevenin resistance equivalent to be 571.43 ohms

    I am stuck on finding the thevenin voltage.

    Could someone explain this to me ? Possibly show me the first few steps?
    I was told to turn the voltage into a current by dividing 5V/1kohms = .005A

    I'm not sure what to do next.
    [​IMG]
     
  2. cloud18

    New Member

    Sep 6, 2011
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    You can try these techniques (Mesh, Nodal or Source Transformation)
     
  3. illidari

    Thread Starter New Member

    Aug 26, 2011
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    Not exactly familiar with those
     
  4. JoeJester

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    Apr 26, 2005
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  5. illidari

    Thread Starter New Member

    Aug 26, 2011
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    I tried the node voltage method. I'm stuck on solving it. I attached the work I got done with it.

    I'm still lost on how to move forward.
     
  6. Jony130

    AAC Fanatic!

    Feb 17, 2009
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    Now you can turn the 5mA current source into the voltage source
     
  7. wo0t

    New Member

    Jan 21, 2011
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    is the thevenin voltage 2001.67V ?
     
  8. Jony130

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    Feb 17, 2009
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    No
    Vth = 8005/7 = 1.143KV
     
  9. wo0t

    New Member

    Jan 21, 2011
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    if you don't mind, can you share with me what is the step to get 1.143kV ? Thanks !
     
  10. Jony130

    AAC Fanatic!

    Feb 17, 2009
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    We can write down the nodal equation directly form the diagram

    [​IMG]

    I1 = Va/R4 + (Va - Vc)/R2

    (Va - Vc)/R2 = Vc/R3 + (Vc - V1)/R1

    Or we can use source transformation technique

    [​IMG]

    And now we can find Vab voltage

    Vab = V2 - I1*R4 = V2 - (( V2 - V1) / ( R4 + R2 + R1||R3 )*R4 ) =

    = 2KV - (( 2KV - 5/3) / (1KΩ + 1KΩ + 1KΩ/3 ) *1KΩ ) =

    = 2000V - 856.428571V = 1143.57143V
     
    wo0t likes this.
  11. wo0t

    New Member

    Jan 21, 2011
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    Thank you very much ! :)
     
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