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Re: uestion

Original poster: FutureT@xxxxxxx

In a message dated 4/12/05 11:17:04 PM Eastern Daylight Time, tesla@xxxxxxxxxx writes:

1. When tuning (at low power and with a target next to the toroid) is there
a max spark length one can get? Is there a mathematical equation for this?
I've seen the following eqn, but I imagine it does not apply to the sparks
obtained when tuning your TC.

spark length (inches) = 1.7* input power (watts)


The formula should be

  spark length (inches) = 1.7*sqrt input power (watts).

The spark length may follow the formula at lower powers
when tuning but will most likely fall short.  As the power is
reduced, the sparks tend to have more trouble meeting the
formula's "predictions".   For example my old research
coil gave 42" sparks at about 610 watts.  But my smaller
TT-32 coil only gave about 26" sparks at 380 watts.  So
the larger coil met the formulas expectations, but the smaller
coil did not.  I didn't try simply lowering the power of the
TT-42 to see if the sparks gradually failed to match
the formula as the power was reduced.  That would have
been a good test but I never tried it.  My guess is that
the sparks would have begun to fall short of the formula's
expectations.  Only fairly efficient coils will reach the
formula's expectations in general.

John Freau