It 's been just over a year since we got to talk about a project given by the laboratories of MIT Massachusetts Institute of Technology, and the inherent possibility of achieving a particular system transfer electricity without wires .
then it is only a draft submitted on paper, conceptually very good, but who still had not addressed the practical tests to demonstrate the actual applicability to real situations. We learn in these days that the same research team, led by Professor Marin Soljacic , has finally been able to achieve a practical demonstration of the project, creating a "wireless loop" which allowed the lighting of a normal bulb 60 watts.
The particular circuit involves the use of two copper coils by 60 cm in radius, one of which is connected to an ordinary power outlet and provided with a drive so that it can generate a magnetic field characterized by a precise resonant frequency.
1 - coil connected to the mains, 2 - Power outlet, 3 - Obstacle; 4 - coil connected to a light bulb;
The second coil is characterized by the same resonant frequency (in this case is 10Hz), which causes the coil to resonate when it is early in the magnetic field generated by the first. This phenomenon means that the coil starts to flow a electricity, which can be used for normal use.
The circuit has allowed, as I said, lighting a 60W bulb, demonstrating an efficiency of about 50% at a distance of two meters and with a barrier placed between the two coils. He is currently studying the use of materials other than copper, such as silver, in order to reduce the size of the coils and increase efficiency. Professor Soliajic notes in this regard, that the achievement of efficiency between 70% and 80% would be sufficient to ensure its use for most applications.