Nikola Tesla, the undisputed godfather of electrical engineering had visions of transmitting power without the use of wires. His attempts however were not recognized and the industrial world was more than willing to go in for the wired transmission of power. But Marin Soljacic, an assistant professor of physics at MIT has engineered a solution which promises to transmit power without the need for wires and with a fair amount of efficiency. The main principle behind the solution is that of resonance. In this case, magnetic resonance was used. In resonant inductive coupling, energy can be easily exchanged by two resonators which are tuned to the same frequency. The energy is transferred via evanescent waves. In normal electromagnetic induction, a primary coil connected to a power source generates a magnetic field and a secondary coil which lies within this magnetic field induces a current in the circuit to which it is connected.
However, lots of energy gets wasted in the process. A simpler example of Marin’s concept would be that of a glass which shatters when a singer sings at its resonating frequency. Marin and his colleagues have successfully demonstrated that using this technique, they can transfer power over short distances without wires at a relatively higher efficiency. Also, this technology is relatively safe for for biological organisms and does not affect electronic equipment nearby. In their demonstration, they hung up two resonant coils from the ceiling about two meters apart and managed to light up a 60 watt bulb in spite of a wall placed in between.
Though the power transmission range is small, it has a wide range of applications particularly when it comes to electronic devices. Wireless charging of ipods, cellphones, cameras etc will certainly make life a lot easier for a lot of us. However, this technology needs to improve the efficiency and range of power transmission for it to become truly revolutionary.
Source : Technology Review
