RE: I've lost my k. Can someone help me find it?

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

Original poster: "John H. Couture by way of Terry Fritz <twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>


Dan -

Look for a resonant frequency with the secondary coil ends open with no
connection and also the resonant frequency with the secondary coil ends
connected together. You will get two different frequencies and these can be
used in the equation to find the K factor. You can do the same with the coil
inductances but they are usually very close together so this is a more
difficult test.

A challenge for any coiler is to do all four K factor tests of their coil
and end up with results that are within +/- 10% without doing very much
tweaking.

John Couture

-------------------


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Tuesday, September 24, 2002 4:33 PM
To: tesla-at-pupman-dot-com
Subject: Re: I've lost my k. Can someone help me find it?


Original poster: "Daniel Barrett by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<dbarrett1-at-austin.rr-dot-com>


    Hi hohn-
    Can you clarify what exactly you mean by 'open' and 'shorted' in this
context?


> You may have seen the Open/Short test in my Tesla Coil Construction Guide
>
>     K = sqrt(1-(Fo/Fs))  or  K = sqrt(1-(Ls/Lo))
>
> Fo = frequency when secondary coil open
> Fs = frequency when secondary coil shorted
> Lo = inductance when secondary coil open
> Ls = inductance when secondary coil shorted
>