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Find current through inductor after many time constants.

  1. Apr 12, 2017 #1
    1. The problem statement, all variables and given/known data
    In the figure, R = 1.9 kΩ and ε0 = 60 V . When the switch is closed, the current through the inductor rises to 10 mA in 30 μs .

    What will the current in the circuit be after many time constants?

    2. Relevant equations
    I = V/R or I = ε/R if current is constant which after many time constants it should be correct?

    3. The attempt at a solution
    So I attempted to use I = ε/R, but that presented the wrong answer. So then I thought about the question and I remembered that after many time constants that is essentially saying a τ→∞ which would make ε = IR and again I = ε/R so I am not lost on where my thinking was going and if I was even correct in the initial process?

    Attached Files:

  2. jcsd
  3. Apr 12, 2017 #2


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    Staff: Mentor

    What, precisely, was the value that you calculated and entered?
  4. Apr 12, 2017 #3
    I got 31.5789 A, which is taking ε = 60V and R = 1.9 Ω. EDIT: The Ω where in kΩ. I just needed to convert it and got the correct answer.
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