The Symbol " Q "

Discussion in 'Energy & Fuel' started by Hal Pollner, Feb 13, 2020.

  1. Hal Pollner

    Hal Pollner Veteran Member
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    (Only Fred, Faye, and possibly 1 or 2 others on this Forum beside myself understand what the electrical symbol "Q" means.)

    "Q" is the "Figure of Merit" of the Quality of an Inductor or Coil.

    It is given by the ratio of Inductive Reactance to the Resistance of the Inductor in question, at a specified frequency.

    Thus, an Inductor with a Reactance (XL) of 1200 Ohms and a Resistance (R) of 5 Ohms has a "Q" of 240 at that frequency.

    "Q" is determined by the formula XL divided by R, where XL is from the formula: XL=2piFL. or 2 pi times the Frequency "F" in Hz by the Inductance "L" in Henries.

    That's all...

    Hal
     
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  2. Frank Sanoica

    Frank Sanoica Supreme Member
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    @Hal Pollner

    We had an old guy teaching A/C theory at DeVry Technical Institute long ago, likable, very knowledgable, comical. He came up with an unusual representation involving Q, Xl, and R which stated "Fo / Q". He said think of it as ....."Foe - Q".
    Frank
     
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  3. Thomas Stearn

    Thomas Stearn Veteran Member
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    You seem to know the inside out. ;) Just wanna say that I'm not one of those.
     
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  4. Hal Pollner

    Hal Pollner Veteran Member
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    Ahhhhh yes, Thomas.....but your skills and talents are found in many other areas, I'm sure!

    Hal;)
     
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  5. Thomas Stearn

    Thomas Stearn Veteran Member
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    Well, it should have been “know them...“ of course.:rolleyes:
    Must keep looking...
     
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  6. Faye Fox

    Faye Fox Veteran Member
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    I never understood why Q stood for quality. It seems to me it should be E for efficiency. Higher reactance with less resistance = more efficiency. I told the high IQ old man next door he was low Q and he needs to change his frequency because his reactance is low and his resistance is high to my reasonable request to clean up his trash that blows in my yard.
     
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