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Homework Help: Kirchoff's loop rule

  1. Sep 11, 2013 #1
    1. The problem statement, all variables and given/known data

    Compute the current through R2 of the circuit in the figure.

    2. Relevant equations
    kirchoff's loop rule

    3. The attempt at a solution
    Junction: I1+I2=I3

    Alpha loop: V1-I3R3-I5R5=0

    Beta loop: V2-I8R8-I5R5=0

    *without one of the currents provided I am not exactly sure where to proceed from here...any help would be greatly appreciated! Anything that is a different color than black in the figure is what I added to the circuit diagram! Thank You PF!

    Attached Files:

  2. jcsd
  3. Sep 11, 2013 #2


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    You have two of the currents (in terms of other variables) so you can find the third.
  4. Sep 11, 2013 #3
    I have been trying to figure out the algebra but I am always left with two variable (grouping of I1, I2, or I3). I am not sure how I can get it down to just one variable for current...
  5. Sep 11, 2013 #4


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    start here:

    I3 = I1 + I2

    and you know what I1 and I2 are, yeah? So....

    I3 = ?
  6. Sep 11, 2013 #5

  7. Sep 11, 2013 #6


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    I'm not sure what you did there... I1 and I2 will be in terms of I3 and your knowns.

    Actually, I'm not quite sure what you did for your alpha/beta loops either. There is no I5 or R5 or I8/R8. Don't try to plug in your values yet, just use the names of the constants.
  8. Sep 11, 2013 #7
    I think I figured it out I have a value of 1.076A through R2. really appreciate the help :)
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