Re: In vs. Out
From: Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Monday, July 28, 1997 5:42 PM
Subject: Re: In vs. Out
Some nice thoughts in here....
> From: FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
> Sent: Sunday, July 27, 1997 8:55 AM
> To: tesla-at-pupman-dot-com
> Subject: Re: In vs. Out
> In a message dated 97-07-27 10:28:20 EDT, you write:
> << at the risk of being somewhat of a radical here, why not try a totally
> > different tact - let us imagine that input power is at least well defined
> > in theory measurable (a hot wire and a photo cell being one way).
> > Imagine a "quality" metric which is a function of 2 variables - spark
> > and overall intensity. Max spark length can be measured,it's a number of
> > meters (feet, centimeters, Ells, whatever unit you choose)
> > Intensity can also be objectively measured - a convenient unit is total
> > brightness, measured using a "standard" photo cell with a "standard" lens.
> >This could be cheap stuff, like a silicon solar cell from Radio shack with
> > lens, at a specified distance, or a cadmium sulfide photo resistor mounted
> > a disposable camera body.
> > The quality metric should give a bigger number for more brightness,and for
> > more spark length. So, I would recommend something of the form:
> > (brighness/K)*spark length
> > Select K so that given agreed units of brighness (ohms mesured on the
> > cell, candellas, lumens per steradian, again, whatever you agree on) the
> > result of a bright spark divided by K will be close to 1, that way a "weak
> > spark" will be penalized in a standard maner, and a nice thick spark will
> > suitably rewarded.
> > Note that you would also want to average the reading over several seconds.
> Nothing radical there, I was thinking of something similar. In theory this
> should work. It solves the brightness variable. Somehow though, if
> someone built a coil that gave a monstrously bright, but very short
> spark, and we had to give it the same efficiency rating as a coil with
> a much longer but dimmer spark...it just wouldn't seem "right"
> somehow even though it is technically correct...hmmm.
> John Freau
I would like to suggest that rather than being held of a measure of
resistance (which as we all know is continuously changing), spark
brightness is a pretty good measure of current to a first order
approximation. Length might be seen as the "sustaining" voltage for
an arc. The product of the two would give a first order power
approximation. This is only going to work for optimal loading however.
Long air streamers are quite dim by comparison and a lot of energy is
wasted in the gap under this condition. However, a summation of these
spark parameters at _both_ ends of the system could be useful as a
total in-system power approximation.