Re: Coily Things

To: tesla-at-poodle.pupman-dot-com
Subject: Re: Coily Things
From: Tesla List <tesla-at-stic-dot-net>
Date: Thu, 20 Mar 1997 23:43:49 -0600
Approved: tesla-at-stic-dot-net
Subject: 
            Re: Coily Things
       Date: 
            Fri, 21 Mar 1997 10:35:57 +1200
       From: 
            "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
Organization: 
            Wellington Polytechnic, NZ
         To: 
            tesla-at-pupman-dot-com


Hi all,
         As promised, here with Mark's permission is part of a post 
to me relating the side frequencies to k. I have snipped personal 
bits and irrelevancies from the post and inserted an additional note.

Malcolm

 ------- Forwarded Message Follows -------

Date sent:      Tue, 11 Feb 1997 03:33:17 -0600 (CST)
From:           mrbarton-at-ix-dot-netcom-dot-com (Mark Barton)
Subject:        Re: Coily Things
To:             "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>


  I've got some cool equations for you that I worked out a while 
ago which relate f1 & f2 to K.  Since f1 = fo/sqrt(1-K) and f2 = 
fo/sqrt(1+K) ... squishing we get fo = sqrt(2/(1/f1^2 + 1/f2^2))  
This relates the 3 frequencies   and K.  Further squishing gives the 
magical equation:  K = 1 - 2 / (1 + (f2^2 / f1^2)).
  This means that you can set up a coil, short the spark gap, connect
a signal generator to the primary, sweep for the two peak freqs,
and then DIRECTLY COMPUTE K!!  I like this method because it is so
direct and gives the real effective K value.

<SIDE NOTE>: I have used this same method for some years now. However,
I have used the approximation of k = df/F (which is in close agreement
for k's of .2 or less) - MW <END NOTE>.

>- Greg Leyh has been examining some successful coils and has reached 
>the conclusion that a Zs of around 40 - 50 kOhms is a useful value to 
>reach in the secondary. I can't remember whether that was including or 
>minus the terminal but I think it was including.
>

  My experience has been the higher the Zsec the better.

ZZZZZZZZzzzzzzzzzzzt,
--MB