GhostOfCaptSpaulding
07-24-2009, 12:41 PM
[offsite:1oyln5nu]Wireless power system shown off
A system that can deliver power to devices without the need for wires has been shown off at a hi-tech conference.
The technique exploits simple physics and can be used to charge a range of electronic devices.
Eric Giler, chief executive of US firm Witricity, showed mobile phones and televisions charging wirelessly at the TED Global conference in Oxford.
He said the system could replace the miles of expensive power cables and billions of disposable batteries.
"There is something like 40 billion disposable batteries built every year for power that, generally speaking, is used within a few inches or feet of where there is very inexpensive power," he said.
Trillions of dollars, he said, had also been invested building an infrastructure of wires "to get power from where it is created to where it is used." ...
...The system is based on work by physicist Marin Soljacic at the Massachusetts Institute of Technology (MIT).
It exploits "resonance", whereby energy transfer is markedly more efficient when a certain frequency is applied.
When two objects have the same resonant frequency, they exchange energy strongly without having an effect on other, surrounding objects.
For example, it is resonance that can cause a wine glass to explode when a singer hits exactly the right tone.
But instead of using acoustic resonance, Witricity's approach exploits the resonance of low frequency electromagnetic waves.
http://i233.photobucket.com/albums/ee162/21b45o13x25c54o34d45e/witricity_.gif
[list=1:1oyln5nu] Magnetic coil (Antenna A) is housed in a box and can be set in wall or ceiling.
Antenna A, powered by mains, resonates at a specific frequency.[/*:m:1oyln5nu]
Electromagnetic waves transmitted through the air.[/*:m:1oyln5nu]
Second magnetic coil (Antenna B) fitted in laptop/TV etc resonates at same frequency as first coil and absorbs energy.[/*:m:1oyln5nu]
Energy charges the device.[/*:m:1oyln5nu][/*:m:1oyln5nu][/list:u:1oyln5nu]
The system uses two coils - one plugged into the mains and the other embedded or attached to the gadget.
Each coil is carefully engineered with the same resonant frequency. When the main coil is connected to an electricity supply, the magnetic field it produces is resonant with that of with the second coil, allowing "tails" of energy to flow between them.
As each "cycle" of energy arrives at the second coil, a voltage begins to build up that can be used to charge the gadget...
...The system is able to operate safely because the energy is largely transferred through magnetic fields.
"Humans and the vast majority of objects around us are non-magnetic in nature," Professor Soljacic, one of the inventors of the system, told BBC News during a visit to Witricity earlier this year.
It is able to do this by exploiting an effect that occurs in a region known as the "far field", the region seen at a distance of more than one wavelength from the device.
In this field, a transmitter would emit mixture of magnetic and potentially dangerous electric fields.
But, crucially, at a distance of less than one wavelength - the "near field" - it is almost entirely magnetic.
Hence, Witricity uses low frequency electromagnetic waves, whose waves are about 30m (100ft) long. Shorter wavelengths would not work...
BBC | Wireless power system shown off | Videos (http://news.bbc.co.uk/2/hi/technology/8165928.stm)[/offsite:1oyln5nu]
Didn't Tesla do this first?
What's the angle?
Why's it "new" now?
Wait, is it because they've figured out a way to limit the range and attach a meter?
Hmmmm...
Kewl tech, 100 years after the fact...
A system that can deliver power to devices without the need for wires has been shown off at a hi-tech conference.
The technique exploits simple physics and can be used to charge a range of electronic devices.
Eric Giler, chief executive of US firm Witricity, showed mobile phones and televisions charging wirelessly at the TED Global conference in Oxford.
He said the system could replace the miles of expensive power cables and billions of disposable batteries.
"There is something like 40 billion disposable batteries built every year for power that, generally speaking, is used within a few inches or feet of where there is very inexpensive power," he said.
Trillions of dollars, he said, had also been invested building an infrastructure of wires "to get power from where it is created to where it is used." ...
...The system is based on work by physicist Marin Soljacic at the Massachusetts Institute of Technology (MIT).
It exploits "resonance", whereby energy transfer is markedly more efficient when a certain frequency is applied.
When two objects have the same resonant frequency, they exchange energy strongly without having an effect on other, surrounding objects.
For example, it is resonance that can cause a wine glass to explode when a singer hits exactly the right tone.
But instead of using acoustic resonance, Witricity's approach exploits the resonance of low frequency electromagnetic waves.
http://i233.photobucket.com/albums/ee162/21b45o13x25c54o34d45e/witricity_.gif
[list=1:1oyln5nu] Magnetic coil (Antenna A) is housed in a box and can be set in wall or ceiling.
Antenna A, powered by mains, resonates at a specific frequency.[/*:m:1oyln5nu]
Electromagnetic waves transmitted through the air.[/*:m:1oyln5nu]
Second magnetic coil (Antenna B) fitted in laptop/TV etc resonates at same frequency as first coil and absorbs energy.[/*:m:1oyln5nu]
Energy charges the device.[/*:m:1oyln5nu][/*:m:1oyln5nu][/list:u:1oyln5nu]
The system uses two coils - one plugged into the mains and the other embedded or attached to the gadget.
Each coil is carefully engineered with the same resonant frequency. When the main coil is connected to an electricity supply, the magnetic field it produces is resonant with that of with the second coil, allowing "tails" of energy to flow between them.
As each "cycle" of energy arrives at the second coil, a voltage begins to build up that can be used to charge the gadget...
...The system is able to operate safely because the energy is largely transferred through magnetic fields.
"Humans and the vast majority of objects around us are non-magnetic in nature," Professor Soljacic, one of the inventors of the system, told BBC News during a visit to Witricity earlier this year.
It is able to do this by exploiting an effect that occurs in a region known as the "far field", the region seen at a distance of more than one wavelength from the device.
In this field, a transmitter would emit mixture of magnetic and potentially dangerous electric fields.
But, crucially, at a distance of less than one wavelength - the "near field" - it is almost entirely magnetic.
Hence, Witricity uses low frequency electromagnetic waves, whose waves are about 30m (100ft) long. Shorter wavelengths would not work...
BBC | Wireless power system shown off | Videos (http://news.bbc.co.uk/2/hi/technology/8165928.stm)[/offsite:1oyln5nu]
Didn't Tesla do this first?
What's the angle?
Why's it "new" now?
Wait, is it because they've figured out a way to limit the range and attach a meter?
Hmmmm...
Kewl tech, 100 years after the fact...