RF energy harvesters. Any working schematics for one?

[tcmtech]

I have been seeing more and more online about these little self tuning RF energy harvesters as of lately that apparently tune into local power line frequencies or harmonics radiating off of them or into the carrier signals of radio stations and what not and am wondering if anyone has a working schematic for such a device.

From what I am reading they are low power devices that only generate a few volts at a few tens of milliwatts at best which make them highly limited as power sources of course but apparently work rather well as a low powered single cell battery chargers.

So has anyone got one or ever designed a circuit that actually works?

Here is one link to what I am talking about.

https://www.extremetech.com/extreme...r-that-gathers-free-electricity-from-thin-air

Just curious how it's done especially at the low frequency end of the spectrum!

 

[JimB]

Smoke and mirrors!

I suspect that the device in the video was simply responding to the presence of an electric field.

Notice how it flashed when he stroked the dog, just simple electrostatics.

And when he was perving at the sweet fraulein talking on her mobile phone, it was just registering the electric field from the transmitter in the phone.

No significant energy harvesting, just a show to impress those who dont know.

JimB