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Homework Help: Determine currents ib and ia

  1. Sep 18, 2012 #1
    1. The problem statement, all variables and given/known data
    Determine ib and ia

    Ix = 0.4 mA, R1 = 15k ohm, R2 = 19k ohm, R3 = 23k ohm, R4 = 15k ohm

    2. Relevant equations


    3. The attempt at a solution
    I am assuming there are 4 unknown currents in this diagram.
    Ix splits into ib and i1.

    0.4mA - ib - i1 = 0
    i1 - i2 = ia

    R2*ib - Vo + R1*(0.4mA - ib) = 0

    R3*ia + R4*(0.4mA - ia) = 0

    I am confused about the independent current source. In some problems, I have seen it carry a voltage. So if I include a voltage in my analysis for that loop I will have another unknown.

    Vx(0.4mA) + R1(0.4mA - ib) + R3(ia) = 0
    Last edited: Sep 18, 2012
  2. jcsd
  3. Sep 18, 2012 #2


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    Gold Member

    Hint: Vx can be calculated from Ix and the series/parallel combination of the resistors. Then Ia and Ib are easily calculated.
  4. Sep 18, 2012 #3
    Thank you, that makes sense
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