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Homework Help: Circuit Analysis Parallel RLC

  1. Dec 2, 2014 #1
    1. The problem statement, all variables and given/known data
    2. Relevant equations
    Resonant Frequency = 1 / [2 * pi * squareroot(LC)]
    Inductive Reactance = 2 * pi * f *L
    Capacitive Reactance = 1 / (2 * pi * f * C)
    Q = XL/Rw
    BW = fr/Q

    3. The attempt at a solution
    The information in the handy dandy jpeg I created is LITTERALLY all the information I was given for a take home exam. My instructor has never given an analysis problem that couldn't be solved, especially when there are only 2 on the exam. An electrical engineer friend and I couldn't tackle it. Without either the Capacitor, Inductor, or Reactance values I don't know that I have enough given information to solve. If I am wrong, then I lose 20% off my exam.
  2. jcsd
  3. Dec 2, 2014 #2


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    Science Advisor
    Homework Helper
    Gold Member

    As a non EE myself, I have two questions:
    1. What does XL stand for?
    2. Are you supposed to get help on the internet for your take-home exam?
  4. Dec 3, 2014 #3
    We are allowed to collaborate, use books, the internet, seek help. My instructor never said to reach out for help. Even if this is the only time I've ever needed to reach out like this on a homework problem. Our finals are Monday of next week. I think he didn't want to spend a whole class period doing the exam.

    XL stands for inductive reactance. It is the inductors opposition to current through an inductor. Inductive Reactance equals 2 x pi x frequency x inductance. It is answered in Ohms.
  5. Dec 3, 2014 #4


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    Staff: Mentor

    Hi Keenan. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif [Broken]

    You start with this equation: BW = fr/Q
    determine the unknown, then you move to another of those equations you supplied ...

    BTW, I'm not sure what Rw stands for, but I'll pretend it stands for winding resistance
    Last edited by a moderator: May 7, 2017
  6. Dec 3, 2014 #5
    RW is winding resistance.
  7. Dec 3, 2014 #6
    I cannot believe I didn't see that ...
  8. Dec 3, 2014 #7
    Q = 12
    XL = 120
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