Well, I'm not using a supply rail or anything at all, I'm trying to scavenge EMF radiation that is everywhere around starting from nothing.
I have a large (about 50m²) metallic roof which I'm using as an antenna for picking up the ambient EMF. I can't really tell what I am picking up, it seems I'm picking up some radio signals, some satellite signals, powerlines power etc.. If I look at the FFT of the signal I get from that roof, there are some definite peaks, one at 166 kHz, another at 183 kHz sometimes and other peaks that appear and disappear randomly. (can't go beyond 200kHz for the FFT on my oscilloscope
)
Anyway, the signal I get is a mix of random stuff, oscillating quite quickly (I can't really measure any precise frequency) and it's varying between approx +/- 1V. So I'm trying to convert that into usable electricity and so far using a cockcroft walton voltage multiplier I was able to get voltages of 5-6V and I could go higher with more diodes. Also, since the oscillations are so low, using germanium (or schottky) diodes gives more voltage since the forward voltage is 0.2/0.3 V. Up to now it's providing me enough energy to light up one or two light emitting diodes continuously..
So I wanted to try using a boost converter to increase the voltage, but I don't want to use any external power, I want to trigger the IGBT using the random scavenged signal, and since it barely goes beyond 1V I need an IGBT with a very low Vgs value.
The circuit would be somewhat similar to that:
I'm not an expert so I don't really know which other transistor I could use which would act a a switch instead of the IGBT on that drawing. Because what I studied at university about transistors was always with dc supplies, without any supply I'm kind of lost on how to switch on/off a jfet, bjt,mosfet or anything else!