Recharging cell phones remotely

New York Times : WiTricity Corp in Massachusetts is developing technology that would allow smart phones, tablet computers, and similar small electronics to recharge wirelessly. The technology is based on magnetic induction, the process used to recharge electric toothbrushes, writes Anne Eisenberg for the New York Times. A magnetic coil in the charging station creates an alternating electromagnetic field, and a second coil in the device takes power from the field and converts it back into electrical current to charge a battery. Whereas electric toothbrushes have to be very close to their base to recharge, WiTricity extends the charging range to as much as 3–4 feet by setting the coils in the device and in the charging station to resonate at the same frequency. If their method proves successful, the company plans to expand the technology to include electric cars and electronic medical implants such as pacemakers.