WiTricitic Power : Electricity without CablesMIT Lab Discovers the Power of the Universe
A team of scientists at the Massachusetts Institute of Technology have demonstrated a wireless power transfer scheme they have dubbed 'WiTricity' or wireless electricity
The concept behind the technology is simple and based on the idea that two resonant objects on the same resonance frequency can exchange energy efficiently.While the demonstration was of a 60W globe being powered from a source over two metres (seven feet) away, a more popular application could be to recharge electronic gadgets such as mobile phones, making them truly wireless.
The key: Magnetically coupled resonance
Objects tuned to the same resonant frequency can transfer energy efficiently over some distance (like a tuning fork separated from a resonating musical instrument at the same pitch) with little energy dissipated to surrounding objects with different resonant frequencies. The MIT team had previously worked out the necessary resonance conditions that would ensure relatively efficient electrical power transmission and used their calculations to design two electromagnetically resonating coils coupled by their magnetic fields.
A key point is that WiTricity does not use electromagnetic radiation, which would be inefficient and possibly hazardous. Instead, it relies on magnetically coupled resonance which gives efficient energy transfer and interacts very weakly with most common materials including living creatures. "The fact that magnetic fields interact so weakly with biological organisms is also important for safety considerations," said researcher Andre Kurs.
The system uses a pair of copper coils. One generates a magnetic field oscillating in the megaHertz range, and the other resonates with that field and converts the energy back into electricity. In comparison with magnetic induction (as used in electrical transformers), resonant coupling remains efficient when the two coils are not very close together.
And a very astute critically entertaining read
