RE: K formula?

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

Original poster: "Peter Lawrence by way of Terry Fritz <teslalist-at-qwest-dot-net>" <Peter.Lawrence-at-Sun.COM>

John,
      I did a google search for, I think, "coupled resonance", and found

K = (Fu^2 - Fl^2) / (Fu^2 + Fl^2)     exact
K = 2 * (Fu - Fl) / (Fu + Fl)         approximate, and very close at low K

I think you've given something equivalent to the "approximate" formula,
but notice how close .1104 and .1107 are.

I'll be writing up something on how I took these measurements soon, I want
the feedback from this group on whether it was a legitimate test or not,
but it's not that easy to describe, perhaps this evening when real work
is more out-of-the-way.

-Pete Lawrence.




 >Original poster: "John H. Couture by way of Terry Fritz 
<teslalist-at-qwest-dot-net>"
<couturejh-at-mgte-dot-com>
 >
 >
 >There is another method of finding the K Factor. This is a much simpler
 >method and you have a better chance of getting it right.
 >Or do you?
 >
 >Find the resonant frequency first
 >    Fr = F1 + (F2 - F1)/2
 >       = 193.42 + (216.1 - 193.42)/2
 >       = 193.42 + 11.34
 >       = 204.76
 >
 >     K = (F2 - F1)/Fr
 >       = (216.1 - 193.42)/204.76
 >       = 0.110763
 >
 >Note that this gives you a slightly different K Factor. The other K factor
 >is 0.1104. Which is correct? Rounding off numbers or avoid squaring numbers
 >when possible?
 >
 >John Couture
 >
 >-------------------------------------
 >
 >
 >-----Original Message-----
 >From: Tesla list [mailto:tesla-at-pupman-dot-com]
 >Sent: Tuesday, July 29, 2003 2:09 AM
 >To: tesla-at-pupman-dot-com
 >Subject: Re: K formula?
 >
 >
 >Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz
 ><teslalist-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>
 >
 >Tesla list wrote:
 >  >
 >  > Original poster: "Peter Lawrence by way of Terry Fritz
 ><teslalist-at-qwest-dot-net>" <Peter.Lawrence-at-Sun.COM>
 >  >
 >  > Is there a formula for the K (coupling coeff) given that I know the two
 >  > resonant frequences that the combined primary plus secondary have.
 >
 >Given the frequencies F1 and F2>F1:
 >k=(F2^2-F1^2)/(F1^2+F2^2)
 >
 >  > at 0"   193.42  and  216.10  KHz resonances,  22.8 Hz appart
 >k=0.1104
 >
 >Antonio Carlos M. de Queiroz
 >
 >