Is it possible to convert electromagnetic waves around into a free power supply? (Not a MegaWatt one of course!)
I've heard about some circuits which do so...
Thanks, Ali
Yes, if You live nearby a middle-wawe transmitter (over a kW), with tuned aerial - possible lighting.
Many years ago i've built a receiver (MW) without battery.
You just need a tuned circuit, and tap off at a suitable low impedance for what you want to drive.
But you need to be VERY close to a VERY high power transmitter.
The radio Sebi mentioned is called a 'crystal set', they simply use a tuned circuit and a rectifer, feeding either high impedance (2000 ohm) headphones, or a crystal earpiece.
The very early domestic radios were like that (before valves), the rectifier was a piece of crystal, and you made contact to it with a 'cats whisker', a very fine piece of wire - apparently the skill was in finding a sensitive part of the crystal. I'm sure searching for 'crystal set' will find loads of hits!.