Re: TC & Lightning 3

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


Yes, it can be useful for TC measurements.  It can accurately measure peak
potentials.

We use a 14 inch dia. VDGRF sphere with an insulated 2 x 2 inch curved piece
of metal.  The curved piece is placed over some insulating tape so the
device acts as a capacitor with internal diodes (fast response diodes)
(inside the 14 inch sphere).  This is signal fed out through a standard BNC
connector back to a storage scope.

We usually operate the TC in a single shot mode using a series string of 10
nine kV diodes to rectify the power xmfr output.  These diodes in series
with a series string of 1 watt small resistors to produce 5 meg Ohm at 30 kV
DC (1 kV across each resistor).  This slows down the charging rate of the
cap and usually fires the sparkgap once every 3-5 seconds (5*R*C).  We
derive the primary firing potential by measuring the pri sparkgap length and
then using that chart I posted (through Terry's archives) early this year.

The scope measurement is calibrated against a 300 kV DC Cockroft-Walton
multiplier for accuracy.

Amazingly, the scope values are within 3% or less of the measured discharge
path from the coil's toroid to a 7 inch dia. ground sphere.  This allows us
to accurately measure the output of both small, medium, and large TC's with
good accuracy.

You could also run the output across a resistor and then use a 0-25 uA DC
meter as a tuning device for TCs.  This also works very well and allows you
to see the best output as you adjust the primary tap.    This step can be
maddening for larger coils as it's more difficult to detect a 6 inch spark
difference in a coil with a 10 ft spark.  Using the meter or DSO allows you
to "see" the best tap location in real time.

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913
 >
I have often
wondered how to build a device that would monitor static buildup in the
clouds.  I have also wondered if this device would be useful for a Tesla
  Coil.