Re: Back to the basics - tuning techniques

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Original poster: acmq@xxxxxxxxxxxxxxxx 

> Original poster: "C. Sibley" <a37chevy@xxxxxxxxx>
>
> Hey All,
>
> After running my first pig powered coil, I had the misfortune of
> blowing a capacitor.  With subsequent rebuilding and retuning the
> coil is runnig smooth now.  I blame the trouble with the initial tuning.
>
> Question, I remember reading once regarding tuning with a frequency
> generator and an oscilloscope.  Can anyone point me to such
> directoins?  Is there any other method to get the tuning "just right"
> without relying on dead reckoning?
>

The method that I use is:

Adjust a signal generator to produce a ~1 kHz square wave with high
amplitude. Connect the signal generator and a 1 Ohm resistor in parallel
across the spark gap (power off, of course). Observe the voltage over the
primary inductor in the oscilloscope. Adjust the primary tap until you
observe complete notches in the oscillations that appear after each
transition of the square wave.
http://www.coe.ufrj.br/~acmq/tesla/tefpreg1.jpg
This is the ideal tuning point without streamers. Set the primary
inductance to a bit more than the point found to account for the increased
terminal capacitance in the presence of streamers, or connect a wire to
the secondary terminal with the approximate length of a streamer and
adjust the primary coil in the same way, this time accounting for streamer
load.

Antonio Carlos M. de Queiroz