Re: Measuring k

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: Re: Measuring k
From: Tesla List <tesla-at-stic-dot-net>
Date: Wed, 17 Sep 1997 00:20:35 -0500
Approved: tesla-at-stic-dot-net


From: 	Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: 	Tuesday, September 16, 1997 9:21 PM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: Measuring k

Hi Julian,
 
> From:   Julian Green[SMTP:julian-at-kbss.bt.co.uk]
> Sent:   Tuesday, September 16, 1997 12:04 PM
> To:     tesla-at-pupman-dot-com
> Subject:    Measuring k
> 
> I don't have a inductance meter, but I do have a scope and
> I have recently been examining waveforms of my coil running
> under various conditions. (I hope to provide pictures of 
> scope traces if anyone is interested).
> 
> >From the scope trace I can see the point that the spark gap 
> quenches and also determine k.
> 
> Please correct me if I'm wrong:
> 
> Spark gap quenches when the lobes finish and smooth decay
> envelope starts.
> 
> k can be measured by counting the number of cycles to achieve
> maximum potential  (on my coil this is 3 indicating a coupling
> of 0.33)

k = 1/(2 x T x Fr)  where T = time taken to ringup (half a complete 
beat hump). The formula is an approximation for the lossy case.

Also approximate:  k = (Fhi-Flo)/Fr   where Fhi and Flo are the two 
sideband responses you can see when running the primary from a signal 
generator and monitoring the two response frequencies on a scope.

Malcolm