Apparently so! Wireless power? I have a hard time wrapping my head around this one, but the thought certainly is fascinatinig!!
That'd be awesome. I always wonder about something like that when I look at the mess of cables behind my computer desk.
This would be amazing if they came through. How cool would an iMac look?! The only cable running off of it(if you have the wireless keyboard and might mouse) is the power cable.
My toothbrush charges this way today. However the coils are almost touching. Losing 60% over 7 feet isn't terribly interesting. Besides, where does the energy go? And besides, Tesla had this sussed a hundred years ago.
One has to remember that there are two kinds of fields associated with conductors (like wires and antennae): a near field and a far field. Or, to put it another way, energy that is stored in the field in the vicinity of the conductor and energy that is radiated away. Radiated energy arising from accelerated currents (radio waves) could be recovered and used for power, though it would be a very inefficient method. It would be difficult to keep these waves from carrying energy off in all directions and, of course, anything operating near the same frequency would interfere/be interefered with. But the energy stored in the field around the conductor is another matter...er, energy. It's fairly easy to recover without connecting wires. In an AC power line (like the 60Hz systems in our homes), that energy is stored, drained, and replenished as the voltage goes through its full cycle. That energy is temporarily stored in the field but is eventually returned to the conductor, so no energy is lost. You could measure this field around the wiring in your house, even in a leg where no current is flowing (i.e., the switch is off). Good thing, too: if this energy was not recovered by the circuit, then you would be consuming electric power (and running up your bill!) even with every electric device in your house turned off. Another properly-designed circuit placed in close proximity to this field, however, can tap that energy. You may have seen or heard of someone standing under big power transmission lines and holding up a flourescent tube, which lights in the presence of the field. Similar thing. The flourescent bulb lights because there is a time-varying electric field eminating from the power line and a bulb aligned with this field will get a potential difference across its length and so currents will flow. Of course, if the power company finds out you're lighting flourescent tubes this way, you're liable to get a visit from some city employees with firearms. Because you're STEALING power. Just like these lines emit produce an electric field which extends radially out from the wire, they also produce a magnetic field, which sort of circulates around the wire. This magnetic field grows, shrinks, grows in the opposite direction, shrinks, and grows again as the current in the power line goes through its cycle. If a coil of wire is placed perpendicular to the changing flux of this magnetic field, a current will be induced in the wire (the little circular UHF antenna on your old TV works like this, only with the magnetic field of radiated waves). That current carries energy which, now siphoned from the power line, can be used in another circuit. But, again, stealing energy. So, the main thing needed to tap this near field energy is a coil connected to a circuit that is resonant at whatever frequency the field is changing at (probably 60Hz). Unfortunately, the lower the frequency, the larger the antenna has to be, and so I expect that a fairly big coil is needed for this to work with household electricity.
