RLC combination help

Discussion in 'Homework Help' started by Camelcampbell, Feb 22, 2014.

  1. Camelcampbell

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    Feb 22, 2014
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  2. shteii01

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    Feb 19, 2010
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    Just upload pic to imgur and link, or photobucket, or flickr, or whatever other pic hosting service.

    (rhetorical question) Why such simple thing like posting a pic is such pain in the a$$? (end of rhetorical question)
     
  3. Camelcampbell

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    Feb 22, 2014
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  4. shteii01

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    Part a.

    *Replace inductors with jwL.
    j is unit imaginary number
    w=60 Hz, this is given to you when they told you about the source
    L is inductance of the inductor, you only have one.

    Replace capacitor with 1/(jwC)
    j is same as above.
    w=60 Hz
    C is capacitance of the capacitor, you only have one.

    Now you have calculated impedance of the inductor and capacitor. The unit of impedance is Ohm. Meaning, you replaced inductor and capacitor with their resistor equivalent. So now you have purely resistive circuit. Some of your resistors are in series, some in parallel. Find equivalent resistance, that is your total impedance of the circuit.
     
  5. Camelcampbell

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    Feb 22, 2014
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    What do you mean by "imaginary number"? Are you referring to the component method?

    I've gotten as far as determining XL=3.77ohms and XC=17.68ohms just not sure where to take it from there....
     
  6. Camelcampbell

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    Feb 22, 2014
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    According to the answer sheet:
    a) 3.55ohms
    b)33.21
    c)10.9 degrees lagging current
    d)33.21amps
    e)6.389amps
     
  7. Camelcampbell

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    Feb 22, 2014
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    Do you mean j is -90 or 90 degrees?
     
  8. shteii01

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    XL and Xc denotes reactance. You need to take it a step further. You need impedance.

    To answer your other question:
    +j is 90°
    -j is -90°

    Also. 1/j is equal to -j. So 1/(jwC)=-j/(wC)
     
  9. anhnha

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    Apr 19, 2012
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    I am sure you meant f = 60Hz.
     
  10. Camelcampbell

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    Feb 22, 2014
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    Ok yeah so impedance of LR1 is 6.262ohms and CR2 is 20.312ohms
    Where do I go from there?
     
  11. shteii01

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    Yes, thank you.

    w=2*pi*f=2*pi*60
     
  12. shteii01

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    That can not be right because I don't see j.

    Also. I am sorry for making earlier mistake. w=2*pi*f
    In your case f is given, it is 60 Hz.
     
  13. shteii01

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  14. Camelcampbell

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    Feb 22, 2014
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  15. JoeJester

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    I think the answers you posted in post number 6 has problems. Answers b and d can not be the same.

    The others are suspect as well.
     
    Last edited: Feb 23, 2014
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