Comments for "Wireless Power Experiments"

4th July 2014 21:17

Amer Voloder wrote ...

Hello Alan, yet again your wireless power experiments page is excellent anfd very helpfull for my project.

I succeded in making the project work and transfer energy using two inductors.

I'm making a project and it is about lighting systems for the truck trailers. I'm trying to avoid the connectors and direct physical connection and use magnetic field for this purpose instead of.

My question is now, do you think, is it possible to send current through a long cable with two thin wires inside which is placed around the trailer to produce B field and 'catch it' with receiver inductor which is placed inside the lighting package? With no physical connection.



30th January 2013 23:40

Gaurav Lonkar wrote ...

Congrats Alan and I'm now implementing your project. I want to know the exact specifications of the Tx and Rx inductors (coils). I'm finding it difficult to read the specifications given in the circuit diagram.

4th September 2011 00:00

bryam wrote ...

alan greeting

I could give a list of materials please

26th April 2011 22:11

Alan Yates wrote...


Are you suggesting such a device is over-unity efficiency? I'd really, really like to see a working model if you are suggesting that.

I did not examine your paper in detail, but I'd guess the total energy delivered to the system losses does not exceed that injected into the system from the power source. A loop 1/4 wave away reflecting energy back to the driven loop is not at all surprising, (1/4 wave spaced or not, something near-resonant in the near-field will exchange energy with the driven element - implying some phase-shift associated with its spacing and impedance) but I strongly doubt this can just create energy from nothing. My guess would be you have not modeled the losses properly, or have not considered the change in load presented to the generator, invalidating the boundary conditions. That said, electromagnetics is not my area, but conservation of energy is always a good bet.

Build it and measure.



19th April 2011 05:59

Xiaodong Liu wrote ...

I found the source will not output power but absorb power if the distance to the receiver is 1/4 of wavelength. In that case, the system is an energy multiplier since both source and receiver obtain energy.

26th January 2011 15:21

Alan Yates wrote...


Yep looks like I'll be build a spectrometer at some point...

No it won't light in the primary alone, the impedance is too low at the relatively low power levels so the electric field never gets strong enough to cause ionisation.



26th January 2011 15:19

Alan Yates wrote...

Smiki and Hubert,

Thanks for that. Indeed an interesting effect and a most visual demonstration of the MFP. Might have to play with that a bit more, I have a vacuum system that I have never really used sitting here and at one time I was a pretty good glassblower...



26th January 2011 14:02

Alan Yates wrote...


Interesting idea to use a CD. I have a piece of plastic pressed grating here that I've always been meaning to build into a spectrometer... I had visions of using a linear CCD from a fax machine as the detector, but for this experiment my eyes should work just fine. :)



19th January 2011 23:25

John Chapman wrote ...

You mention NE2 bulbs emitting a purplish light in addition to the normal neon colour; and that you needed to get a spectrometer.

Have a look at a range of DIY spectrometers using cereal packets and bits of CDs on a site written by Jorgen Koppen. Much better than I have made it sound!

John Chapman Plymouth UK

18th January 2011 08:02

Brett_cgb wrote ...

Re: purple Neon light:

I'm not certain, but you may be ionizing the neon gas to its second ionization (a second electron is removed from the atom). When the 2nd electron returns to the atom, it emits a higher energy photon with a shorter wavelength (near blue; in combination with the orange emission, this appears to be purple).

Re: Fluorescent light

In traditional fluorescent lamps, an electric field generated by applying a voltage using electrodes excites the mercury gas to ionize and emit UV light. The UV then excites the phosphor on the inside of the tube to create visible light.

Lamps with electrodes (including sodium vapor, mercury vapor, neon) fail as the electrodes degrade.

Induction lighting uses magnetic fields to generate circulating currents within the gas and cause it ionize.

I would be very interested to know if you had tried inserting the fluorescent tube in your Tesla primary in place of the secondary. Did the tube light?

Overall, a well done project. Thanks!


18th January 2011 01:14

Hubert wrote ...

Hi, I like your work, as base for my own experiments.

Maybe you will try to light an geissler tube instead of the fluorescent tube, when changing the pressure insiden you can get those moving patterns to staning discs of light. I have found a page where this is described,

Sorry this is only german, but google translate may help

I have had accidently energy transmission when I powered my Magnat ION Tweeter without shielding, it happened that a ca. 1MHz TC lying on the table began to arc.

Now a , Your TC stands on metal, doesn´t this metal base work as a shortened coil, that will suck energy from the field???

greets Hubert

18th January 2011 00:00

smiki wrote ...

Just a comment to the quantized dark and bright regions.

It's a sort of an avalanche effect. In a standard scenario it goes like this: An electron is emited from the cathode. It accelerates towards the anode. The higher the speed the higher the energy it carries. Since the space between the cathode and anode is not ideal vacuum, there is a lot of gas atoms floating around. So the electron traveling is going to collide with some atom sooner or later. The average distance it can travel without a collision is the Mean Free Path. So the electron accelerates, travels roughly a distance of one mean free path then collides with a gas atom and it gets excited. When the atom deexcites it radiates a photon of appropriate wavelength. And as photons work, the higher the energy the shorter the wavelength. These photon can be in any region of the spectrum, infrared, visible, UV ...

But for your luck there is the luminescent layer of the tube which absorbs UV and around UV and transforms it to visible light too.

After the first collision the electron again gets accelerated (if the accelerating field is still there) and again travels roughly one MFP and collides, exciting a gas atom etc ... And then again and again. These are the dark and bright regions.

Mean free path by definition is the average distance of travel. Collision that happen in shorter distance has much lower energy, producing lower energy photos (infra). Analogically for the longer distance collisions (far UV photons). These are invisible (dark regions)

Of course in your case you don't have an anode and cathode and a static accelerating field, but the effect is the same, just the field gets reversed 20 million times a second :)

So the distance between the two bright areas is exactly the Mean Free Path. It's proportional to the gas pressure.

Suggestions for further experiment: Try two different tubes with different pressure, the regions should be spaced differently at the same power level. If you know the pressure you can even calculate the mean free path and compare your measurements. I've done that at the university many years back, and it was surprisingly accurate

15th January 2011 22:46

Koogar wrote ...

Great videos and write up very understandable even for the layman

Best Regards


15th January 2011 14:28

Tom wrote ...

Excellent article. Thanks. If you do scale up to breakout level, here's a couple of pointers:

1) 4:1 aspect ratio for the solenoid wound secondary is the sweet spot as far as efficiency goes. This is from years of experimentation by the Tesla coiling community. Though the physics of why is beyond me.

2) Don't couple too tightly. This can cause voltage gradients in the secondary that are beyond the insulating properties of varnished wire, causing racing arcs up and down the secondary. Looks pretty, but after winding a couple of 1000T 1.5m secondary coils this gets old really fast!

A short vid of my 800W spark gap coil (over 1m arcs)

6th January 2011 08:23

Jorge Garcia wrote ...

Excellent job with this tutorial. I usually work with switchmode power supplies, and your tutorial has helped me to better understand how resonant converters work. So even though not a wireless application, thank you for the information and the effort you put into this.

Best Regards,

Jorge Garcia

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