As any circuit is solved (simplified), generators opened or closed etc.
finally an equivalent R, XL and XC are found.
Of course a real inductor is not only inductance as well a capacitor is not
pure capacitance, they are already a resultant of different sign reactances
plus losses (a resistance) that's frequency dependent.
By itself, anyway, the Q has no straight relation with resonant frequency
but's a number obtained with R, XC and XL.
Found the effective values of equivalent XC, XL and R (C and L & R) the
parallel and series resonance is exactly the same and is found when XL
equals XC.
73,
Mauri I4JMY
----- Original Message -----
From: "Peter Chadwick" <Peter_Chadwick@mitel.com>
To: "measures" <2@vc.net>; "amps" <amps@contesting.com>; "'Michael Tope'"
<W4EF@dellroy.com>
Sent: Wednesday, April 25, 2001 9:42 AM
Subject: RE: [AMPS] basic question about dipping the plate
>
> Rich says;
>
> >When XL = XC, a series or a parallel circuit is resonant
>
> It depends on how you define resonance. A parallel tuned circuit can be
defined
> as resonant when
>
> 1. XL = XC, OR
> 2. when the voltage across C is maximum OR
> 3. when the current through L is maximum OR
> 4. when the impedance is maximum OR
> 5. when the applied V and I are in phase
>
> They all give different answers when you take finite Q into account. XL =
XC is
> a convenient approximation for use when Q is relatively high. With a low
Q, it
> fails.
>
> By using the definition of resonance as V and I in phase (or power factor
= 1),
> you get identical definitions for both parallel and series circuits, and
much
> easier analysis of both low Q and coupled circuits.
>
> Thus a low Q circuit according to Rich's definition will have a different
> resonant frequency to that according to Tom's definition. Personally, I
prefer
> the V and I in phase, but provided that you state which definition you are
using
> it doesn't matter.
>
> 73
>
> Peter G3RZP
>
> --
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>
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