??? 12/17/06 18:49 Read: times |
#129644 - Sort of Responding to: ???'s previous message |
Some RFID tags work by the energy they receive through their antenna.
A "crystal set" radio produces sound direct from the received radio signal with no batteries or power supply. But these are not just random signals - this is receiving specific transmissions. If the field strength were strong enough to give enough power to charge batteries, etc, it would probably be dangerous to your health! |