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Homework Help: Mesh Circuit Analysis

  1. Jan 5, 2010 #1
    1. The problem statement, all variables and given/known data
    Determine the Voltage across Resistor R6.


    2. Relevant equations

    3. The attempt at a solution
    I called the bottom left Loop I1, the bottom right I2 and the top I3. All currents are flowing clockwise. From there I set up my KVL expressions for each loop:

    -12 + 5600(I1-I3) + 5600(I1-I2) + 5600(I1) = 0
    5600(I2-I1) + 5600(I2-I3) + 5600(I2) + 5600(I2) = 0
    5600(I3-I1) + 5600(I3) + 5600(I3-I2) = 0

    From there I simplified those equations into these:

    I1(16800) + I2(-5600) + I3(-5600) = 12
    I1(-5600) + I2(22400) + I3(-5600) = 0
    I1(-5600) + I2(-5600) + I3(16800) = 0

    Plugging the Matrices into my calculator I end up with:
    I1 = 9.82A
    I2 = 3.57A
    I3 = 4.46A

    I checked the answers and ended up getting 120008 = 12 for the first equation, 0 = 0 for the second and -56 = 0 for the third. Obviously I did something wrong, but hell if I know where. I've done Mesh many, many times before and this particular problem is just a pre-lab thing for a simulation but something is wrong and I just don't know what. If anyone can help me out here I would greatly appreciate it!


    EDIT- NEVERMIND! I decided to solve it out by hand and noticed I got the exact same answers just x10-4 and plugged them in my calculator again... turns out I couldn't be assed into scrolling to the side to see the E-4 after those numbers. WHOOPS!
    Last edited: Jan 5, 2010
  2. jcsd
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