a warm welcome to all,
i am going to make a project on wireless power supply.it is just a prototype
of Witricity.BUT thyere is some problem
i want to design a collpitts oscillator with frequncy 10MHz and input power around 500W
if someone has any idea please respond

Ask Mr-914 :smiley:

Oh my god, I’m getting referenced in bizarre topics.

I only know about microwave energy transmissions. Do a search in a journal database for the title, “Popular Science” and keywords microwave airplane. I’m sure there are only a couple of articles that will pop up.

A wireless power supply. A bit like cold fusion, no?

Well, not w/o cooking any carbon based life-form in the general vicinity.

Would love to hear if this science fiction could indeed be science fact.

It’s true, it can be done.

I’ve researched this in the past, but I was surprised when I just re-read the article on the efficiency a moment ago…

microwave wireless energy transfer is rated at 0.5% efficiency.

Then again, just saw these… sh*t!

$35 cordless extension cord works up to 300 ft (“safely”)


I love the disclaimer:

Warning: Even though these microwaves are about as harmful as the leakage from an ordinary microwave oven (not much), do not put computers, televisions, other sensitive electrical equipment, food, liquids, paper, glass, flammable substances, magnets, or living things in between the base and satellite units. Just in case.

are you thinking of using similar techniques to those used by MIT in this paper?


according to their experiments, over a 2 meter distance, they were able to power a 60 W light bulb…but their power input was around 400 W. my question is, what would you like to power, and what kind of efficiency are you aiming for?

thank you for responses.
BUT can someone help me in

  1. making a collpitts oscillator of input power around 200-500 Watt at frequency 10MHz
  2. making a bridge rectifier were input power is around 50W at frequency 10MHz. :bulb:

Please don’t say it a fiction
In 1904 St.louis World fair transmitted 75W of power upto 30m
then NIKOLA TESLA did many experiments and was able to transmit power upto 40km .even though not all his experiment were proved BUT LACK OF EVIDENCE IS NOT EVIDENCE OF LACK.
In june 2007 came WiTricity ,Headed by Prof Marin Soljasis
Many companies like e-coupled,powercast systems etc are transmitting power wirelessly.

I agree with you that scientific theories are worth pursuing. That said, 5% efficiencey for power transmission?

Aren’t we in a world now where inefficient power transmission in actual productization is not where its at?

To counter your “Lack of Evidence” comment:

Just because you CAN do it, doesn’t mean you SHOULD do it.

Focus your pursuits on boosting this kind of power transmission to 80% without cooking every water filled organic creature that crosses the path of transmission and I tell you what…come to me and I will help you manufacture the thing.

Not really related to your application, but along the same line…

Powercast is wireless, low-voltage power for powering cells phones and the like. Supposedly the technology will be out on the market next year (incorporated into products).

It intelligently adapts to multiple loads - from milliwatts to kilowatts - and spatial configurations while maximizing > energy transfer efficiencies by as much as 98%, making eCoupled technology comparable to hardwired connections in terms of energy costs> .

→ From their website…

98% Efficient, or 98% /more/ efficient [than comparable products] ?

One means it’s 98% efficient, the other means it is 0.99% efficient!

edit: Okay, other parts of the site have more firm wording, maybe it is something good.

just came across this today. didn’t read it, sounds interesting from a glimpse. only 25% loss.

Intel Moves to Free Gadgets of Their Recharging Cords

Published: August 20, 2008
SAN FRANCISCO — Intel has made progress in a technology that could lead to the wireless recharging of gadgets and the end of the power-cord spaghetti behind electronic devices.

It says it has increased the efficiency of a technique for wirelessly powering consumer gadgets and computers, a development that could allow a person to simply place a device on a desktop or countertop to power it. It could bring the consumer electronics industry a step closer to a world without wires.

On Thursday, the chip maker plans to demonstrate the use of a magnetic field to broadcast up to 60 watts of power two to three feet. It says it can do that losing only 25 percent of the power in transmission.

“Something like this technology could be embedded in tables and work surfaces,” said Justin Rattner, Intel’s chief technology officer, “so as soon as you put down an appropriately equipped device it would immediately begin drawing power.”

The presentation is part of the company’s Intel Developer Forum, a series of events here that the company uses to showcase new technologies in personal computing and related consumer technologies.

The research project, which is being led by Joshua R. Smith, an Intel researcher at a company laboratory in Seattle, builds on the work of the Massachusetts Institute of Technology physicist Marin Soljacic, who pioneered the idea of wirelessly transmitting power using resonant magnetic fields. The MIT group refers to the idea as WiTricity, a play on wireless and electricity. Both the M.I.T. group and the Intel researchers are exploring a phenomenon known as “resonant induction,” making it possible to transmit power several feet without wires.

Induction is already used to recharge electric toothbrushes, but that approach is limited by the need for the toothbrush to be placed in the base station.

The M.I.T. group has demonstrated efficiencies of 50 percent at ranges of several meters.

Intel is in the midst of an internal debate over whether the technology may also permit the shift to supercapacitors, which can be recharged far more quickly than today’s batteries. “In the future, your kitchen counters might do it,” Mr. Rattner said. “You’d just drop your espresso maker down on them and you would never have to plug it in.”

The Intel team describes its system as a “wireless resonant energy link,” and is experimenting with antennas less than two feet in diameter to remotely light a 60-watt light bulb.

In 2006, the M.I.T. researchers demonstrated that by sending electromagnetic waves around a waveguide it was possible to produce “evanescent” waves that could permit electricity to wirelessly tunnel to another waveguide “tuned” to the transmitting loop.

Several start-up firms , including WildCharge, based in Boulder, Colo., and WiPower, based in Altamonte Springs, Fla., have already announced related wireless charging technologies. But these demonstrations have required that the consumer gadgets touch the charging station.

The Intel researchers said they were thinking about designing a system that would make it possible to recharge a laptop computer without wires.

“From Intel’s position that seems like the thing to shoot for right now,” Mr. Smith said. The receiving antenna is about the size of something that could easily fit against the bottom of a conventional laptop computer. “It could be that cellphones and P.D.A.’s are even more compelling, but I think we are going to start with the laptop. It’s easy to dial down from laptops,” he said.

The researchers said that Intel could produce a prototype design and that it might contribute to products by developing chip sets for manufacturers. At Thursday’s research presentation, Mr. Smith plans to demonstrate an application using an electric field sensor — a natural capability of some fish — to give added dexterity to robotic arms and hands. He has designed a sensor system that makes it possible for a robot hand to gauge the size of an apple and then grasp it. The hand then carries the apple to an outstretched human hand. When it senses the hand, it drops the apple.



Bosch and Lomb had in the late 80’s chargers that would penetrate a closed watertight plastic housing and charge the product. Plug the product into the charger and the unit would receive a trickle charge through a thin wall. I mentioned this to a major cellphone manufacturer in Chicago in the middle 90’s and the dismissed it without even thinking about it.

I remember a lighting designer in Atlanta in the early 90’s who would experiment with a lamp that all it had to do was sit next to an outlet and it would take power to light. Electricity creates a field that builds around an outlet is rather nasty bubble for the less than 1amp body cant be healthy… but millions of Americans place their bed next to an outlet and put thier head inches away from the outlet. (Ouch) Not really recharging if you ask me. :astonished:

The NSA and FBI have small listing devices that when simply placed near a conduit will pull a small trickle of energy off the grid. Thats been around since the 90’s too.

We’re already having a huge problem with vampire power from wired devices, isn’t going wireless just going to make it worse since they just keep transmitting non-stop whether or not a device is in the area?

Design engine: You are talking about inductive charging: Inductive charging - Wikipedia

It is still used on Braun electric toothbrushes.