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Homework Help: Concept of L-C circuits

  1. Mar 28, 2009 #1

    This is just a conceptual question I have for the image below.
    http://img22.imageshack.us/img22/7489/44840348.jpg [Broken]

    If the switch is turned off at t=0, why is the voltage across the voltmeter=20V? I understand that current in all inductors is zero. But wouldn't at t=0, current would need to pass through the first resistor, and therefore a voltage has dropped making voltmeter reading less than 20V?

    Thank you in advance.
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Mar 29, 2009 #2
    First consider a simple LC curcuit. Apply kisrchoff's and solve the differential equation for current. You will get that An inductor behaves like infinite resistance at t=0 and a pure conductor at t=infinity. Form this i think that you would be able to solve the problem

    And just for extra information: A capictor behaves like a pure conductor at t=0 and as an infite resistance at t=infinity
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