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Homework Help: Differential Equations RLC Circuits

  1. Dec 2, 2011 #1
    1. The problem statement, all variables and given/known data

    A series RLC circuit has an electromotive force given by E=200e^(-100t) V, a resistor of 80 ohms, an inductor of 0.2 H, and capacitor of 5x10^-6 F. If the initial current and charge on the capacitor are zero, find the current at any time t>0.

    2. Relevant equations


    3. The attempt at a solution

    i am not begging for someone to solve the whole problem for me, just to get it started
  2. jcsd
  3. Dec 2, 2011 #2


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    Homework Helper

    OK, start by observing that the same current is flowing through all three components (R, L and C) at any time t because they are in series. Call this current [itex]I(t)[/itex].

    Let the voltage drop across each of the components be represented by [itex]V_R(t), V_L(t)[/itex] and [itex]V_C(t)[/itex].

    Can you now list some equations relating [itex]I(t)[/itex] to each of those voltages?

    What can you say about the sum of those three voltages (Kirchoff's laws)?
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