Sweet spots, break rates, etc.
More observations and comments:
1. A corregated toroid may need to be as much as double the
size of a smooth toroid to insure just one breakout, and to obtain
the same spark length. Large toroids may increase the spark length
mainly by reducing the number of simultaneous streamers. A bump
placed onto a smaller toroid may result in the same spark length, but
spark may be a little dimmer.
2. Spark length seems to correlate very strongly with output
power rather than voltage, at least within some range. This makes
precise toroid sizing and secondary geometry much less important
than otherwise. A tall narrow secondary may be just about as good
as a short wide one.
3. High break rate sparks may have more of a tendency to arc
downward and hit the primary for a given toroid size and spark length.
4. Question: Do high break rates become more efficient at higher
power levels? I cannot test this, but I could build a smaller TC
(smaller than my present one), and see if high break-rates become
even less efficient at even lower power levels, which might give
some clues to the question. It would be interesting if the efficiency
of high break-rates is strongly power-dependent. I've never heard
anyone suggest this before. Comments?