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Need help in step response circuit diagram

  1. Nov 19, 2016 #1
    This isn't a homework question! I posted the question for context purpose.

    So I understand that at t>0 the switch moves to b. Hence the first circuit diagram (pictured) I understand.

    However for the 2nd circuit diagram (picture 2) when asked to transform to s domain. Why does this answer include the 10/s. To my understanding because the switch already switched to b, the 10V is no longer considered hence shouldn't be included as 10/s in the transformation circuit.

    Can anyone explain this to me? Whether the answer key is wrong or are my concepts wrong?

    Thank you so much in advance!!

    Attached Files:

  2. jcsd
  3. Nov 19, 2016 #2


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    The switch was at 'a' for a long time. So what is the voltage across the capacitor at t=0+?
  4. Nov 19, 2016 #3


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    As I can see from picture 1, it asks for the voltage V(t) for ##t\geq 0## so we are interested for the V(t) for t=0 too (not only for t>0).
  5. Nov 19, 2016 #4
    Ah that would make sense..thanks!
  6. Nov 19, 2016 #5
    Um 10V?
  7. Nov 19, 2016 #6


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