No no no, not what you think... more along the lines of "Research and more Research". Finished the Transformer book, didn't have a section on Flybacks but did talk about autotransformers and other interesting things. Nothing about resonance. Ah well.
I dragged the neon sign transformers into the house and poked and prodded on one of them a bit. Passed some modest 5 to 12-volt signals at various frequencies and shapes into it and looked at what came out. Fascinating! Running a sweep into it, I could definitely see how it was tuned for a particular frequency, and then another peak at the harmonic up the scale, and then tapering off to horrible efficiency.
In ordinary transformer mode, I was seeing about 3mA on the secondary (output), with 200 to 250 volts given a fairly tiny input. Nowhere near the rated step up I think, but I was just giving it a trickle of power.
Sine waves were fun, square waves were similar, but pulses were fascinating, giving completely different output characteristics. Then I wired it up with the primary and secondary having a common ground (like a flyback, more or less kinda) and pulsed it there -- and got HUGE spikes off the secondary. Where before there was barely a tingle, in this mode I got painful zaps.
Fascinating.
Can't wait to start pulsing higher voltages/currents through it.