What Am I Doing Wrong?

Discussion in 'Homework Help' started by bembe 24, Aug 10, 2016.

  1. bembe 24

    Thread Starter New Member

    Aug 10, 2016
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    ass2.jpg

    My solution:
    sol.jpg

    Is answer correct? can someone verify my solution... thanks :))
     
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
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    For me solution looks good, but you could write them differently.
     
  3. bembe 24

    Thread Starter New Member

    Aug 10, 2016
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    but is my answer already correct?
     
  4. DGElder

    Member

    Apr 3, 2016
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    C1 + C2 = 1/(1/C1 + 1/C2)

    and where does it say C1=C2=C?
     
  5. bembe 24

    Thread Starter New Member

    Aug 10, 2016
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    so does that make the final answer

    Ls/(Cs/2 +Ls) ??
     
  6. bembe 24

    Thread Starter New Member

    Aug 10, 2016
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    can i really neglect R in the circuit?
     
  7. bembe 24

    Thread Starter New Member

    Aug 10, 2016
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    correct me if i am wrong. If I neglect R in the circuit then C1, L and C2 are in series right?
     
  8. DGElder

    Member

    Apr 3, 2016
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    That is not even a solution because C is undefined.
     
  9. DGElder

    Member

    Apr 3, 2016
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    They are in series whether you neglect R or not.
    The answer is not dependent on R.
     
  10. bembe 24

    Thread Starter New Member

    Aug 10, 2016
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    im sorry my bad. not solution but an equation
     
  11. bembe 24

    Thread Starter New Member

    Aug 10, 2016
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    so if C1, L and C2 are in parrallel, then rewrite the equation with respect to the impedance then does this make

    1/Cs + Ls + 1/Cs right?
     
  12. DGElder

    Member

    Apr 3, 2016
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    Where in that circuit is there a component called C? There is none.
     
  13. DGElder

    Member

    Apr 3, 2016
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    Is it possible you think the s in Cs stands for series? :eek:
     
  14. bembe 24

    Thread Starter New Member

    Aug 10, 2016
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    its a transfer function. from time domain to s-domain. that is what s means
     
  15. DGElder

    Member

    Apr 3, 2016
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    It is a complex number used as the frequency parameter in Laplace transforms. I am glad you know it does not stand for series. So moving on....

    What is the solution to your circuit?

    AND.

    If:
    R = 2000 ohms
    C1 = 3 F
    C2 = 6 F
    L = 5 H

    What is the transfer function?
     
    Last edited: Aug 10, 2016
  16. bembe 24

    Thread Starter New Member

    Aug 10, 2016
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    there were no given values of each component. What you see is what you get :D. Its just a constant variable.
    TF = 5/90s^2 + 9
    is it correct??
     
  17. DGElder

    Member

    Apr 3, 2016
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    It is not correct. I can't help you if you don't show me each step of how you got to your solution.

    Just giving you the answer will teach you nothing.
     
  18. WBahn

    Moderator

    Mar 31, 2012
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    As has already been noted, you can't just assume that C1 and C2 have the same value. So your solution must reflect this reality.

    Also, you need to pay attention to order of operations.

    1/Cs is equivalent to (1/C)s which is equivalent to s/C.
     
  19. bembe 24

    Thread Starter New Member

    Aug 10, 2016
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    new.jpg

    sorry low quality cam :(
    i followed all your instructions. Is this correct?
     
  20. DGElder

    Member

    Apr 3, 2016
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    "Sorry" doesn't make it any more visible.

    If it says what I think it says it is not correct. The setup is correct but your algebra is wrong somewhere and since, once again despite requests, you show none of your steps I can't help you. Maybe you have no steps and are just guessing. Either way I can't help you.

    Also, I think your notation is misleading if not incorrect. It looks like you are subscripting s: s1, s2. There is only one s. Subscript the capacitors: C1,C2. Where applicable, putting s in front of C would make it more legible.
     
    Last edited: Aug 10, 2016
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