From mrbarton@ix.netcom.com Sat Dec  2 07:12 MST 1995
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Date: Sat, 2 Dec 1995 01:29:55 -0800
From: mrbarton@ix.netcom.com (Mark Barton)
Subject: Re: Primary Q's and Spark Gaps
To: tesla@grendel.objinc.com

You wrote: 
>
>O.K., here are some real figures based on measurement of my coil.
>Stats : Lp = 11.8uH (including a couple of feet of stray wiring)
>        Cp = 102nF  (extended foil)
>        Static Gap firing voltage = 7.5kV
>        
>Measured Q (using sig gen and scope - i.e. no spark gap) about 50
>        => Rp about 0.22 Ohms
>              
>Measured Q (operational using ping test and decrement calc.) =11.5  
>        => Rtot = 0.95 Ohms
>        
>        => Rgap about 0.73 Ohms!! (accounts for 3/4 of all losses)
>  

I guess this means your Fo ~= 150KHz.  That 0.1uF cap seems a bit large 
for that freq.  Tesla ran the Colorado lab at 80-100KHz with 0.12uF.  
You know what to do now.  Switch to 0.015uF, about 1/10 what you are 
using now and use a rotary gap.  The reactance of the primary 
components will be 80ohms instead of 10ohms.  Your Q should go way up, 
tuning get tighter, and (hopefully) sparks get longer.

Zap,
Mark



