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Re: Testing without a Coil: Dummy Load?



Original poster: Jim Lux <jimlux-at-earthlink-dot-net> 

At 08:03 AM 1/26/2004 -0700, you wrote:
>Original poster: Matthew Smith <matt-at-kbc-dot-net.au>
>Hi All
>
>Recent posts about a firey spark gap on a coil-less coil begs the question:
>
>Can we hook up a dummy load rather than a secondary, as we can with a 
>transmitter?  If so, what form would this load take?
>
>Cheers
>
>M

Interesting idea... Terry's modeling some years back came up with a 220K 
resistor and some capacitance as a model for the spark load.  The question 
would be whether you could transform that impedance to the primary side. 
(taking into account the loose coupling between primary and 
secondary).  You'd also have the fact that you've got a double tuned 
circuit in the "real situation"..

I could conceive of making a specialized secondary (with many fewer turns), 
corresponding capacitance, and transformed load resistance/capacitance that 
could be coupled to the primary.

I'm not sure what use it would be, though..  You couldn't use it to "tune" 
the coil (since it would be as hard to tune the dummy load as the real 
thing). It might be of use for setting up the primary charging system (say 
you wanted to fiddle with resonant charging, or funky triggered gap timing, 
etc.)