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Power pads, which use magnetic induction, are already on the market, like the Palm Pre's chargin Touchstone, shown here. They only work over short distances, though, and require custom form factors.  (Source:

Witricity uses magnetically couple resonance to transmit power over longer distances, as shown here. The company's CEO predicts the company's technology will be ubiquitous within five years. However, health concerns about the powerful magnet fields it uses remain.  (Source: Business Unusual)
Company believes that computers, phones, and EVs will within 5 years be operating without cords

You can't fault WiTricity for its ambition.  As one of several companies looking to market emerging wireless power transmission technologies, WiTricity is making some of the boldest claims.  Among the claims made by the company -- that within a year wireless power will be taking the mobile electronics industry by storm.

The concept of wireless power transmission is a relatively old one.  In the 1890s, Nikolai Tesla was successful in illuminating incandescent light bulbs with wirelessly transmitted power.  However, for decades this research lay dormant and untouched.

With modern telecommunications and interest in signals at an all time high, interest in the topic again picked up.  The Massachusetts Institute of Technology, in particular, developed some intriguing technology that WiTricity would later be founded upon.

Eric Giler, CEO of WiTricity says that power transmission over several feet is an obtainable feat.  He states, "Five years from now, this will seem completely normal.  The biggest effect of wireless power is attacking that huge energy wasting that goes on where people buy disposable batteries.  [And] Electric cars [are] absolutely gorgeous, but does anyone really want to plug them in?"

WiTricity isn't the only player in this new market, though.  Several key technologies, each championed by different companies, are emerging.

One is radio power.  Though only able to transmit small amounts of power, this approach can work over a long distance.  A Pittsburgh, Pennsylvania, company called Powercast is among the pioneers in this field, using its technology to power temperature sensors in large office buildings and to power wireless Christmas trees (sold for $400 a piece).  The company has lit up an LED with radio signals from 1.5 miles away.

Another approach is power pads.  Advantages include low costs and relatively high efficiencies.  Disadvantages include the extremely short distance and need for custom shapes and sizes of pads.  This technology currently is employed in the Palm Pre's recharging stone and in electric toothbrush recharging stands.

WiTricity's technology works on a third type of transmission -- magnetically coupled resonance.  Similar to sound waves, the transmission creates a magnetic field, that devices can convert locally to electricity.  This technology enjoys a middle ground with a bit worse efficiency, a bit longer distance, and moderate costs.  Intel is also working on a more efficient version of this approach.

Despite WiTricity's optimism about its new approach, challenges remain.  A full deployment is estimated to possibly create a magnetic field as strong as the Earth's own magnetic field.  According to recent research, referenced by Menno Treffers, chairman of the steering group at the Wireless Power Consortium, such a strong magnetic field can cause serious health risks.

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RE: Tesla
By Fritzr on 9/4/2009 5:44:19 AM , Rating: 2
Yep, broadcast power is alive and well. Every radio (including TV) transmitter is broadcasting power that is tapped by attaching leads to an antenna. The power that is supplied locally powers amps and other accessories. The pure radio receiver & low power speaker can be driven entirely by the broadcaster. I used a crystal radio kit with a 100' ground loop antenna that was just wire unwound from a small transformer to receive Armed Forces Radio Germany ... I was in Suffolk England listening to German, French and English radio stations using a broadcast powered radio.

The drawback to broadcast power is that any power not used by a receiver is wasted.

Short range broadcast systems have the same drawback. Any power not received is part of the inefficiency.

The system they are talking about here is inductance. The "transmitter" is the primary coil of a transformer and the "receiver" is the secondary coil of a transformer. Very basic electrical design. The mystifying part for onlookers us that the two coils are not located in the same case.

If I recall correctly you can build a "wireless" fluorescent lamp fixture using inductance. The light fluoresces due to the presence of the magnetic field. This was a popular demo in Tesla's day and is still occasionally used for science demos.

Yep took a minute to do a Google search and got this Wikipedia page
No conspiracy to bury it other than the usual marketing of whatever will earn money for the corporation. If the Wiki can be believed the induction powered lamps are available today for specialized needs.

RE: Tesla
By Alareth on 9/5/2009 6:27:19 PM , Rating: 2
If I recall correctly you can build a "wireless" fluorescent lamp fixture using inductance. The light fluoresces due to the presence of the magnetic field. This was a popular demo in Tesla's day and is still occasionally used for science demos.

You can use a fluorescent bulb to check for "leaks" on a household microwave oven. Just run it around the outside while the oven is on.

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