Re: [TCML] Spark gap Resistance

[FutureT@xxxxxxx]

In a message dated 11/19/2007 12:43:38 P.M. US Eastern Standard Time,  
bert.hickman@xxxxxxxxxx writes:

David N.  Van Doren wrote:
> Does anyone have any data on spark gap  resistance?
> and for that matter Streamer impedance?
> I've been  doing some simulations, and for the lack of any better number 
I've been using  4 ohms for spark gap R's and have tried using 220kohm+1.5pf'/ft 
for streamers,  but doesn't always seem to look right in the sims. Trying to 
characterize  plasma is always difficult at best.
Dave,
 
An interesting point to consider is that due to the nonlinear gap  behaviour, 
the gap
losses are lowest at the beginning of the primary ringdown.  As the  primary 
energy
decreases, the gap losses increase as a proportion of the remaining  energy.  
Often TC's do not quench on the first notch (first energy transfer to  the 
secondary),
so the energy may make a few round trips from primary to  secondary.  
Apparently
most of the spark length is produced from the initial transfer while the  gap 
losses
are still relatively low.  Thus the gap losses that matter, may be  smaller 
than the
average gap losses.  From a practical viewpoint, a spark gap may  be more 
efficient
that it seems at first glance.  Also, the gap losses can be reduced by  using 
more turns
in the primary (more inductance actually).  However it's also  important to 
use a
large enough capacitor value for a relatively large "bang size".  The  only 
way to  
accomplish these twin goals is to use more turns (higher inductance  
actually) on
the secondary also.  
 
http://hometown.aol.com/futuret/page3.html
 
John



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