Imagine a world without wires – this phrase used to be applicable only when referring to communications such as cellphones and wireless internet. However, some smart guy (and he’s really smart) thought of applying the phrase to electricity itself — and thus wireless electricity or witricity is born. This smart guy scientist is an MIT physicist named Marin Soljacic. He and his group of scientists were able to wirelessly power a 60-watt light bulb located 7-feet away from the power source. They say that they can even power stuff upto 100 watts and in principle even more.
The problems…
Initial thoughts on wireless electricity were cumbersome and even dangerous. One idea was to use laser light but that needs a straight line-of-sight between the power source and the appliance. Another problem is that electricity is wasted when you broadcast it on all directions.
The solution…
The opera singer!!! Soljacic and his colleagues devised WiTricity based off the notion of resonance. Think of an opera singer shattering a champagne glass. The wine glass shatters when the opera singer hits the right note. The resonance of the singer’s voice matches the resonance of the glass. Apparently, two objects exchange energy more efficiently when vibrating at the same resonance – as the glass receives energy from the singer’s voice, it begins to vibrate and eventually shatter.
Now instead of sound waves, our bright scientists used magnetic fields. First because most objects interact very weakly with magnetic fields and second, it’s safe to humans and other biology. In their latest work, they devised two copper coils at about 20 inches in diameter – both of which are designed to resonate at the same frequency. One coil was attached to the power source and another was attached to the light bulb. The result – the 60-watt bulb shined 7 feet away from the power source – wirelessly. Alas! WiTricity!
60W light-bulb being lit from 2m away. Note the obstruction in the lower image. Credit: Science
The applications…
Oh its huge! Imagine not having to plug your laptop anymore. Imagine not having to recharge your cellphone by plugging it to the wall. Imagine getting rid of most (if not all) wires in the house. Though I think that electricity from the powerplants will still be propagated through wires since it’s probably more efficient, the need for wires in the home will definitely be reduce if not totally eliminated.
More futuristic applications…
Think of electric cars! They don’t need to charge and they don’t need wires or even rails – it’s simply a matter of placing wireless power sources at regular intervals along the road and the cars get power! Think about that!
