Re: looking for reference

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

Fairly straightforward to figure it out, qualitatively (sans books)..

LC resonator is an L and  a C in parallel
resonance is when Xl and Xc are equal in magnitude but opposite in sign
Xc is 1/(j omega C) and always negative, and gets smaller as the frequency
goes higher (right.. capacitor -> high pass)
Xl is j omega L and positive, and gets bigger as frequency goes higher...
So, a combination of the two..
As frequency gets higher, the Xc gets smaller and the Xl gets bigger, so the
combination goes positive
As frequency gets lower, the Xc gets bigger and the Xl gets smaller, so it
goes negative

Positive reactance => lagging phase (inductors lag.. positive reactance =>
excess inductance ==> lag)

Now.. consider..
If the generator is lower in frequency than the Fres... The Xc is bigger
than the Xl (f gets lower=> XC gets bigger, XL gets lower)
the current through the inductor will be bigger than the current through the
capacitor (because the reactance is lower-> lower resistance->bigger
current)
Therefore, the net current will be the same direction as the inductor (the
capacitor cancels only part of the inductor).. so it lags,



----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, July 30, 2003 7:25 PM
Subject: looking for reference


 > Original poster: "Peter Lawrence by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <Peter.Lawrence-at-Sun.COM>
 >
 >
 > I'm looking for a reference to a mathematical analysis of the following
 > system: a signal generator is used to excite an LC resonator, and the
phase
 > and amplitude of the LC resonator is related to the frequency difference
 > between the signal generator and the resonant frequency of the resonator.
 >
 > I know I've seen such a derivation, and IIRC when the signal generator
 > frequency is below the resonator's then the resonator phase is ahead of
 > the generator, and vice verse when the generator frequency is above (or
 > I've got it backwards...).
 >
 > I'ld like to see it again, but can't find it in any of the books I still
 > have at home.
 >
 > thanks,
 > Pete Lawrence.
 >
 >