
31-03-2008, 12:42
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They call me Cody.
no team (None currently :\)
Team Role: Mentor
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Join Date: Jan 2008
Rookie Year: 2008
Location: Pontiac; MI
Posts: 408
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Re: witricity legality?
i believe this article should clear up any confusion about witricity.
Quote:
In 2006, Marin Soljačić and other researchers at the Massachusetts Institute of Technology applied the near field behaviour well known in electromagnetic theory to a wireless power transfer concept based on coupled resonators.[8][9][10] In a short theoretical analysis they demonstrate that by sending electromagnetic waves around in a highly angular waveguide, evanescent waves are produced which carry no energy. If a proper resonant waveguide is brought near the transmitter, the evanescent waves can allow the energy to tunnel (specifically evanescent wave coupling, the electromagnetic equivalent of tunneling[citation needed]) to the power drawing waveguide, where they can be rectified into DC power. Since the electromagnetic waves would tunnel, they would not propagate through the air to be absorbed or dissipated, and would not disrupt electronic devices or cause physical injury like microwave or radio wave transmission might. Researchers anticipate up to 5 meters of range for the initial device, and are currently working on a functional prototype.[8]
On June 7, 2007, it was reported that a prototype system had been implemented. The MIT researchers successfully demonstrated the ability to power a 60 watt light bulb from a power source that was seven feet (2 meters) away at roughly 40% efficiency.
"Resonant inductive coupling" has key implications in solving the two main problems associated with non-resonant inductive coupling and electromagnetic radiation, one of which is caused by the other; distance and efficiency. Electromagnetic induction works on the principle of a primary coil generating a predominantly magnetic field and a secondary coil being within that field so a current is induced within its coils. This causes the relatively short range due to the amount of power required to produce an electromagnetic field. Over greater distances the non-resonant induction method is inefficient and wastes much of the transmitted energy just to increase range. This is where the resonance comes in and helps efficiency dramatically by "tunneling" the magnetic field to a receiver coil that resonates at the same frequency. Unlike the multiple-layer secondary of a non-resonant transformer, such receiving coils are single layer solenoids with closely spaced capacitor plates on each end, which in combination allow the coil to be tuned to the transmitter frequency thereby eliminating the wide energy wasting "wave problem" and allowing the energy used to focus in on a specific frequency increasing the range.
http://en.wikipedia.org/wiki/Wireles...nant_induction
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there you go
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Is now an engineer thanks to FIRST.
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