Solve using S-domain analysis

Discussion in 'Homework Help' started by forbi, Oct 4, 2012.

  1. forbi

    Thread Starter Member

    Sep 11, 2012
    37
    0
    Circuit.jpg

    Hi,

    how do i solve for Vs(t) for the above circuit using S-Domain analysis.

    What i have done so far.
    i converted the diagram into S-domain. and using source transformation, i make the current source into a voltage source ,series with the capacitor.

    I did a KVL for both loops to solve for the i(s) at the capacitor (1/S). afterwards i get the Vc(S) of the capacitor as there is no current going through the resistor when t=0. so Vs(t) should be the voltage across the capacitor.

    however, im stuck at the follow equation when doing inverse lap transform.
    Vc(S) = 10/(s^3+3s^2+s)

    how do i go about to convert it into time domain?

    thanks
     
  2. forbi

    Thread Starter Member

    Sep 11, 2012
    37
    0
    IMG_0061.jpg

    here are my workings.
     
  3. forbi

    Thread Starter Member

    Sep 11, 2012
    37
    0
    Anyone could Advice ?
     
  4. rstevenson

    New Member

    Apr 5, 2011
    21
    1
    Vc(S) = 10/(s^3+3s^2+s) do a partial fraction decomposition and then use that to do an inverse laplace to find your time domain response
     
  5. forbi

    Thread Starter Member

    Sep 11, 2012
    37
    0
    how to do a partial fraction on that equation?
    what i get is
    A/S + Bs+c/(s^2+3s+1) .
    but for my demoniantor (s^2+3s+1), it cannot be factorize out
     
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