|
Dr. Mabuse
Septic Fiend
Sweden
9687 Posts |
Posted - 02/24/2013 : 14:56:25 [Permalink]
|
Actually, it really is that simple. A few coils attuned to those EM-frequencies which are most energetic, like the 50Hz mains in Europe. Acting like an antenna the coil generate a small amount of AC current which could be rectified to charge a capacitor.
A few obstacles are the P-N threshold of the diode being relatively high (0,7V), but there are alternatives to that. Shottky diods have lower threshold (~0,3V), and there are some mos-fet transistor couplings which can serve as close-to-zero threshold diodes.
I've toyed with the idea of making a wall clock or an artsy wall-display perpetuum mobile powered by such a device. But I never got it done because I had other projects I felt more urgent.
There are antennas to the older generation cell-phones which as a LED which flashes when the phone is connecting for a call (or simply exchanging data with the cell tower). Those work on the same principle as the battery charger.
Charging an AA-battery within 24 hours will require close proximity to a highly radiating source though.
|
Dr. Mabuse - "When the going gets tough, the tough get Duct-tape..."
Dr. Mabuse whisper.mp3
"Equivocation is not just a job, for a creationist it's a way of life..." Dr. Mabuse
Support American Troops in Iraq:
Send them unarmed civilians for target practice..
Collateralmurder. |
 |
|
Electromagnetic Harvester for Mobile Devices
