What I learned in Joule Theif 101

[d3x0r]

Original schematic here... http://www.overunity.com/10179/joule-ringer/dlattach/attach/49957/image//
From the top, the transformer gets labeled 1, 2, and across the bottom 3,4,5,6

I've wound a toroidal transformer, that worked to light a neon from 0.02A... I wound a study coil, then took 12ft of 24gauge wire and doubled it back on itself 3x (1.5ft 8 strands) and wound them around a toroid.  I already had a length of wire for the primary, so most of this would be the secondary.  I then cut the loops and crossed them so I have lots of taps on the secondry. 

I have a 1-2.4k potentiometer and a few coil-caps that are almost 500pf each.  I have all 3 connected, At 122ohms, the wave is what I expect a joule theif to look like, a low spike on the base and a high spike on the high voltage out.  If I adjust the pot just a little higher, it snaps into an inverted high frequency wave.   If I further increase the resistance, the spikes continue to be inverted, but the freqency lowers, but the voltage is back up to normal.

The yellow line is the high voltage out, the probe is set at 10x and the scale is 2V, so each is 20V [this was spiking much higher, over 100V until something? happened].  The blue line is 2V scale 1x on probe, to monitor that I'm not pulling the base excessively low.   I'm thinking that this higher harmonic inverted thing is the lower power operation mode.  The current and voltage is 0.01A and 1.2V to start at normal spikes, then 0.01A 2.4V is jumped to when the pulses invert, then 0.01A and like 6.8V to have higher pulse voltages.  The interesting thing, is that it's a change involtage with the inverted pulses, where normally one would increase amps to get higher spikes.