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Homework Help: Current through and inductor

  1. Jul 20, 2011 #1
    1. The problem statement, all variables and given/known data

    Find inductor current for t > 0
    http://img192.imageshack.us/img192/5814/unledgo.png [Broken]

    Switch is initially open and closes at t=0+

    The professor wants us to solve these only using the Diff Eq approach. On other questions I would just do a KVL with the inductor loop and solves the resultant ODE. However with this one I would have to do a system of equations. I'm not to sure if thats what I'm supposed to do or even how to do that math.

    I also tried taking the inductor out and doing a thevenin equivalent. I get the correct time constant this way but the constants of integration are way off.

    I really just dont know how to approach this problem.

    fyi I'm told the answer is 6 - e^(-t/6) A,

    whoops sorry for the typo in title, been a tiring day.
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Jul 20, 2011 #2
    Well since i drew up that schematic to post here I figured I'd run the simulation as well. So I havent found my error yet but it looks like doing a thevenin equivalent should yield me the correct answer.

    Is this the best way to approach this problem though? I still feel like I'm missing some key idea here and my book is absolutely terrible at everything but pretty pictures.

    Figured out the problem
    Last edited: Jul 20, 2011
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