# RE: SSTC does 10 foot sparks

```Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com>

>I agree wholeheartedly.

And me! The whole energy vs. power thing is just a red herring. You can
convert between energy and power at will, by just integrating or
differentiating with respect to time. You should get the same answer for
efficiency of your coil no matter which method you use.

Of course, by efficiency, I mean (power delivered to discharge/power drawn
from wall socket). The relationship between power delivered to discharge,
and length of discharge, is a different ballgame altogether, and we
understand it a lot less.

But I still think, from experimental evidence, that power is a better way of
rating things. Freau's formula (spark length that you get about once a
minute= 1.7* square root of power input) works remarkably well.

It works because the spark length, though random, obeys statistical laws. So
the big strike that you get once a minute is related in a predictable way to
the controlled spark length that John Couture is so fond of.

There is no comparable formula that works in terms of energy only. That is
because the spark length achieved by a given energy depends on how fast the
energy is delivered, i.e. the power.

For instance, if I discharge a single 8 joule shot of energy into a pulsed
SSTC over a half-hour period (a power of 4.4 milliwatts) I'll get no sparks
at all. But if I do it in 60 microseconds (a power of 133 kilowatts) I get a
deafening BANG! and a 24" streamer.

Of course, if I set my coil to let off one of these 8 joule, 60 microsecond
discharges every half hour, the average power consumed by the coil would
still only be 4.4 milliwatts and yet it would be doing 24". This
demonstrates why Freau's formula loses accuracy for BPS other than 120.

Confused yet? :))))))

Steve C.

```