WiTricity brings Tesla's
dream
A new system that will allow laptops, mobile phones and televisions
to be left unplugged in the home while being recharged, has been unveiled
by a US company.
WiTricity can send electricity “wirelessly” through the
air and can switch on a light bulb or keep a computer running thanks to a
new development in physics. The outfit hopes to do away with mountains of
disposable batteries and miles of wiring required to charge gizmos and
computers.
Unlike a Tesla device which has the same vision, energy is
largely transferred through magnetic fields without the need for great
flashes of lightning. Boffin Marin Soljacic at the Massachusetts
Institute of Technology, developed the system after he was woken up three
nights in a row by his mobile telling him it had a low battery. His
theory was to use resonance to make it all happen. Resonance means that when
two objects have the same resonant frequency, they exchange energy without
having an effect on surrounding objects.
WiTricity uses the resonance of low-frequency electromagnetic waves and
transfers energy between two magnetic coils. The first coil is placed
in a box attached to a home’s electricity mains, and can be embedded in
a wall or ceiling. The second coil is attached to a device such as a
television or laptop. Electromagnetic waves are transferred between the
two coils and the second coil absorbs energy.
The Institute of Physics in London confirmed that the technology
was safe, as it used a magnetic field that “had no detrimental effects on
the human body”.
Unfortunately it only works on smaller devices which
must be within two metres of a wall that provides wireless power. Later it
is hoped that the range can be extended to as much as 30 metres.