Re: 120 bps vs. 240 bps comparison tests

HI John,

> Original Poster: FutureT-at-aol-dot-com 

> Thanks Malcolm for the nice comment.  I would think that generally
> as Ep is increased, the toroid size should be increased too for
> longest sparks, this is what I've always seen.  I did not actually
> calculate the Vout based on Ctop however.  Can you give a 
> suggestion for how an experiment might easily be done?  I agree
> it doesn't matter much if Ep is increased by increasing Vp or Cp.
> John Freau

Reflecting on the proposed experiment shows how difficult it can be 
to keep things in separate compartments. If one is to keep BPS 
constant and Vp constant, the charging current is going to have to go 
up with primary cap size which = an increase in input power. Nett 
result however is that Vo is constant if total secondary capacitance 
is increased to match (by increasing Ctop) and available charge at the 
top terminal is increased with the same rep rate. My question here 
is: do sparks get longer at the same rep rate as a result of 
increased terminal charge or do they stay the same length and just 
get hotter? I am curious to see the dependence of sparklength on 
available terminal charge. I think it's come out in other experiments 
that there is a sparklength dependence on voltage. I'm making an 
assumption that the change in gap loss isn't going to make a huge 

A suggested approach then is to start out with a gap firing voltage 
that doesn't change, a relatively small Cp and small Cs, and measure 
peak length. Then up Cp and Cs so tune is maintained and adjust 
charge current so that BPS remains constant.

    The point: it is obvious there is a sparklength dependence on 
input power for a given coil but I'm interested in seeing what effect 
the voltage and current have individually. Knowing things like this 
would help explain why some coils do far better than others and 
should point the way to better designs given available components 
and/or power supply.