For long bursts feedback is probably necessary. In my no-feedback coil I
see that the current rises
above the designed limit of the first current beat when streamers
appear. A combination of resistive
and capacitive loading (detuning), probably.
Yes, measurements indicate that capacitive and resistive arc loads are
roughly of equal magnitude, i.e. a phase lead of about 45 degrees of
arc current to arc voltage. For fast growing arcs it is more like 60 degrees.
My idea of a "perfect DRSSTC" would be one using a large primary
inductance, which
could store a lot of energy for a given max primary current and a
corresponding long burst
time to charge it up. That would reduce stress on the transistors.
Most of this is
unexplored territory.
Larger primary inductance reduces the primary current, but reduces the
maximum output voltage
too. Probably, once a certain voltage is achieved bursts length can
control the streamer length.
Again the question that I never saw properly addressed of how much
voltage you need at the output
of a Tesla coil.
Maximum output voltage is not necessarily decreased. More energy in the
primary tank leads to a higher magnetic field if the geometry isn't changed.
That would imply more secondary voltage.
The question of arc length versus voltage is indeed difficult. Arcs of shorter
duration need more voltage for a given length. Also I believe, that higher
TC frequencies require less voltage but more power.
Udo
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