help about this question

Discussion in 'General Electronics Chat' started by TAKYMOUNIR, Aug 27, 2013.

  1. TAKYMOUNIR

    Thread Starter Active Member

    Jun 23, 2008
    351
    1
    Write the equation for the voltage across the capacitor as a function of time after the switch closes
    What is the definition of Q relating inductance, resistance and frequency?
     
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  2. crutschow

    Expert

    Mar 14, 2008
    13,056
    3,245
    That's a good homework question.
    What have you found so far?
     
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  3. TAKYMOUNIR

    Thread Starter Active Member

    Jun 23, 2008
    351
    1
    can you help me
     
  4. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    You will need to show your attempt first. Then, members will help you by pointing out any errors in your attempt, and give you some guidance in putting you on the right track. This forum does not simply do your homework for you.
     
  5. TAKYMOUNIR

    Thread Starter Active Member

    Jun 23, 2008
    351
    1
    v/s=i(s)(R+SL+1/SL)
    I(S)=V/(SR+S^2+1/C)
    I(S)=V/L *(1/S^2+R/L*S+1/LC)
    SO WHAT IS THE I(T)
     
  6. Austin Clark

    Member

    Dec 28, 2011
    409
    44
    I'm actually interested in knowing the answer myself, ha, so you had better figure it out!

    Anyways, as a hint, I'm pretty sure the output over time will be a sine wave, but other than that I can't really tell :)
     
  7. WBahn

    Moderator

    Mar 31, 2012
    17,788
    4,808
    Check your units!!

    Very first line: (R+SL+1/SL) You KNOW that sL and 1/(sL) are not going to have the same units -- unless sL happened to be dimensionless. But if it is, then you know that you can't add it to R.

    So you KNOW this equation is WRONG. No point going any further until you fix it.
     
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