@Dankie
Yes, I was pulsing a low power neon sign transformer that is rated 5kv when driven at 120VAC....I was driving it at 12VDC. So the power spikes were much lower...but definitely HV...at least around 300-500V impulses. (Too hard to tell on my scope...off the charts)
So, yes a random xformer, a random choke, and a random capacitor.
What you have to realize is there was NO AMPLIFIER STAGE in those videos....I was pulsing it straight from the 555 (sharpest signal u can get really, adding amplifier stages degrades the square wave)....So, the power is EXTREMELY LOW!!! Max output from a 555 before it blows up is around 12v @ 190ma....that's around 2 watts...mine were running cool at around 80ma or about 1watt....but, it's a square wave (on half the time)...so the out put is divided by two, so it's really less then 1/2 a watt.
As you can see in this video, the voltage is very high indeed. It is high enough voltage to travel over my dry skin (which is a very large resistance)...this phenomena is very interesting!
You have to understand...ANY setup will have a natural resonance. As long as it include SOME R=resistance L=inductance C=capacitance. So, you could make a random WFC, a random choke coil...and a random transformer. No matter what the values are...that system will resonate at some frequency. You can sweep through the frequencies with a probe on the WFC and see resonance when the voltage spikes up.
P.S. If anyone has a copy of a video I made a while back where I pulsed an ignition coil with a 555 and captured charge on one wire and discharged a xenon bulb....I have lost it and would like it again.
It is another example of resonance....and in fact i made a companion video showing the standing wave all my house and in my oscope w/o a connection made!!