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Homework Help: RL Circuit

  1. Mar 17, 2008 #1
    1. The problem statement, all variables and given/known data
    http://img134.imageshack.us/img134/8382/circujitqt7.th.jpg [Broken]

    i0(0) = 10 A
    i1(0) = 20 A
    The currents through the inductors flow from top to bottom. And v(t) is + on top and - on bottom
    2. Relevant equations

    3. The attempt at a solution

    Find the voltage v(t) over both inductors.
    Since the current going through both inductors is 30 amps total, I get 30*48 ohms
    v(t) = [tex]1440 e^(-600t) [\tex]
    unfortunately, according to my book it's -1440 for the coefficient, what am I doing wrong?
    I really don't see why it would be negative, both of the currents are flowing in the same direction
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Mar 17, 2008 #2
    The current going through the resistor is going from bottom from top. So the bottom must be more positive than the top
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