I'm having a problem solving for voltage between two points

Discussion in 'Homework Help' started by barrett50, Feb 16, 2016.

  1. barrett50

    Thread Starter New Member

    Feb 1, 2016
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    I'm having some problems finding the value for Vx. So far I have found the mesh current equations for all of the loops, and all that's left is Vx. Can someone help me find a starting point for this?
     
  2. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    The fact that you can not find Vx tells me that you don't have mesh currents.
    Nice try though.
     
  3. WBahn

    Moderator

    Mar 31, 2012
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    So... are we supposed to use our crystal balls to see these mesh current equations that you claim to have found for all the loops?
     
  4. barrett50

    Thread Starter New Member

    Feb 1, 2016
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    I didn't say I have the currents, I said I have the equations. The problem comes in at the end of my third KCL that is

    8(Iy-I3) + 6(Iy-I2)+3Vx

    My problem is that I don't know what I'm supposed to substitute in for Vx.
     
  5. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    What is that equal to?
     
  6. barrett50

    Thread Starter New Member

    Feb 1, 2016
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    So I labeled the first box I1, upper mid box is I2, lower mid is I3, and right box is I4. There is a supermesh at I2 and I3. I go clockwise

    I1 = -4 (A)

    KCL at SuperMesh
    3(I3-I1)-2+5(I2)+6(I2-I4)+8(I3-I4)

    KCL at I4 is
    8(Iy-I3) + 6(Iy-I2)+3Vx

    KVL for the dependent current source is
    Iy=(I2-I3)/7
     
  7. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    Anyway. Vx=2+3(whatever currents pass through the 3 Ohm resistor)
     
  8. WBahn

    Moderator

    Mar 31, 2012
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    These are not equations, they are expressions. Equations involve this thing called an equals sign.

    Also, you need to specify which direction your mesh currents are circulating. Otherwise there is no way to know if your value for I1 is correct or not.
     
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