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Determine current using Kirchoff's Junction/Loop Rule

  1. Mar 2, 2013 #1
    1. The problem statement, all variables and given/known data

    In the circuit shown in the figure, R1 = 6 Ω, R2 = 13 Ω, and R3 = 19 Ω, Vemf,1 = 10 V, and Vemf,2 = 15 V. Using Kirchhoff's Loop and Junction Rules, determine the currents i1, i2, and i3 flowing through R1, R2 and R3, respectively, in the direction indicated in the figure.

    2. Relevant equations

    i1 + 12 = 13


    3. The attempt at a solution

    i1 + 12 = i3

    V1 + I3R3 + I1R1 = 0

    V2 + I2R2 + I3R3 = 0

    I1 = (-V1 - I3R3)/R1

    I2 = (-V2 - I3R3)/R2

    I3 = (-V1 - I1R1)/R3

    Does this look right?

    Attached Files:

  2. jcsd
  3. Mar 3, 2013 #2
    The last equation leads you nowhere. Instead, sum the two previous equations, that, together with the first equation, will give you an equation from which you will be able to find I3.
  4. Mar 3, 2013 #3
    Thanks. I was able to solve it.
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