Added: 1 year ago
From: vk2zay
Views: 33,473
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  • cool it helped with my school project, thx

  • very good and informative, thanks for sharing

    i was wondering what will happen if i have let's say a sheet of steel parallel to the primary, wouldn't that create a current in the sheet of metal that is basically a short (similar to inductance cookers let's say :) ). and if not why not.

  • other than electric toothbrushes, are there other examples of cheap wiresless power/inductors around the home which can be cannibalized?

  • Everything is wireless in nature. No cord exists between the sun and a solar panel. Gravity is not powered by energy from a cable. You really believe the heat on your skin actually traveled from the sun to your face? It comes from the same space in which it appears.

    The wireless process we use today does not exist in nature. Which makes it a perversion of nature.

  • Wireless is great! but always think about biological effect on humans, living organisms and Earth electromagnetic equilibrium.

  • Hey Mate Im Very Interested in what you got to say But i Find it Hard to Follow at times because of the Lingo you use to Explaine and the drawn symbolism you use to Show diagram about the Power flow So if ,If you get the time Mate can you Plz Make a tut Explaining the Words you use to Explain things and what the Symbolism you use

  • Can power transfer be harmful to living tissue?

  • Great instructional video, really enjoyed it, thought provoking!

  • I pray that this is not a stupid question. :) According to Faraday, the magnetic field is created around the wire, perpendicular to the direction of flow of current, right? So, what happens if the wire is coiled unto itself? Does the field follow the first winding or does it follow the general flow of the current? I hope I make sense. Thank you for your answer. BTW, the video is amazing!

  • How do you calculate/ whats the equation for the coupling co-efficient (k)!!!!!!!!

  • @iceman77706 You can calculate it from EM theory, but it is dependent on basically everything, so it is usually just measured using mutual inductance.

  • Well done. You are really an engineer.

  • In other words my question is whether the resonance has to do something with transformer design?

  • @MrStudent1978 Resonance and low losses allow reasonable efficiency when the coupling is very low. Typical power transformers have excellent coupling between the windings. Without resonance you'll see very little power transfer and without high-Q the efficiency will be terrible.

    You can check it yourself by doing the maths, or building the circuits - or both. :)

    Either way, it is a fun experiment and I encourage you to try it for yourself, I learnt a lot about the physics involved.

  • Your video has been wonderful.

    I have one doubt-

    Power is transferred from one coil to the other by induction. How does the resonance come in picture? If I make two coils at home, i assume that even if i do not care about what there Q factors are, the power will be transferred. Please do reply to me.

    Should i believe that the home made coils will have small Q factors so resonance band will be wide enough?

  • i haven't watched this properly, but just as an aside in case it's relevant - the type of wireless Wardenclyff used utilised was longitudal waves, like long radio end of the spectrum.

  • in terms of using this to transmit power, which is still then grid dependant (central sources serving lots of buildings etc),

    what are the health effects and effects on the environment, in the line of transmission and surrounding it? given we do know that microwave wireless already fries peoples cells*, and likely disrupts animal navigation.

    *don't anyone argue, you know if you do you're just lying like the evil baccy companies - esp. when they blamed baccy instead of their added toxins to it

  • Amazing how so many likes and no dislikes :o

    Don't see that much.

  • I'm kind of a rookie at electronics, but how come the LED can take AC?

  • @danewwittig LEDs are still diodes, they conduct in only one direction, within limits... In this particular application the peak reverse voltage doesn't exceed their breakdown, and the currents are small enough to get away without using any resistors either. This is not good practice, but acceptable here.

  • @danewwittig LEDs are like any diode, they won't conduct in the reverse direction when the applied voltage it below their reverse breakdown voltage. The LED is actually rectifying the RF and is glowing during less than one half of the cycle times, it is also clamping the amplitude of the voltage across the secondary coil. This isn't a typical or very efficient circuit really, but just the simplest that would work. Directly connecting the LED across the tank is actually very bad for its Q.

  • couldnt we somehow couple to the earths magnetic field and have usable power? it seems so ridiculously simple

  • @LiquidChem

    I believe the earth's magnetic field is spatially varying but temporally constant. So getting the induction effect would be not feasible.

  • Great video! Couldn't you use a microcontroller, and program it to adjust the components to respond to a changing K?

  • Great job! Please how can I contact you? I need something similar for my project. Thanks.

  • Hey thanks so much for a really good video, good luck with all your projects!

  • have u tried a rodin coil for coupling?

  •  hey

    i m like ur video so much & i want to do this project. so can u send me the circuit design.

  • can you charge a phone with that

  • I'm jest beginning in engineering school and we have not fully learned wiring diagrams yet so i was wondering if you could make a video on how to make that in simpler terms

  • @JoelTebo For circuit diagram help have a google, there are many resources out there. I tend to use an mixture of european and US symbols but I think it is fairly standard. For the electromagnetics any good textbook on EM should help. Well worth getting a good grounding in EM, almost all our technology is based on it.

  • This is very helpful! I am working on an induction charger for a device and this was really helpful for helping overcome efficiency issues! Thank you very much for putting this together

  • First of all excellent work! I am just curious to know did you get the rotating display to work.It would be intresting to know wether the flux would transmit from one coil to another when either one of the coils is rotating around the center of the other coil which is not moving.Once again excellent work and thanks.

  • @PBolandii Yes the rotating display works. The software isn't finished yet, I got onto other things before I perfected the PLL recovering the display position phase reference. I should finish it, you are not the only person to ask me about it recently.

    Ah rotating solenoidal fields... That's a classic question people still argue about. Go google it, basically the field doesn't rotate with the coil. The field itself comes from charge motion, you need relativity for a full treatment.

  • @vk2zay You must post up a video when you get ti finished so we can see it.So regradless of the rpm the current still induces form the rotating coil to the stationary coil as the field is stationary.Thats cool!

  • Thank you for sharing your work and experiences. I'm working with the same principle for my final project in College, but I'm trying to use it in medical implants, so this information is very useful for me. I tried to visit your website, but for some reason it says that is not working. I don't know if is a problem with my connection or maybe your website is not working anymore.

    Anyway, congrats for your work and thanks for sharing this.

    Regards from Chile

  • I know a lot of people have been asking for a circuit of the demo TX/RX system, I've added one to my site. Please see the video description box for the URL.

  • Could you show me the schematic you used for you transmitter circuit?

  • Em also working on the same type of module, em working on my university project. will u plz mail me the schematic diagram of your system?? My Coils: Copper wire Coil Diameter = 60cm Turn Spacing = 5 cm Wire Diameter = 4 mm Number of Turns = 5 Length of Coil = 27.4 cm Length of wire = 9.424 meters Please help me out i shall be thankful. Regard rizwan.ar02@gmail.com
  • Men what a great explanation!!! Keep up the good work!

  • doesnt this produce allot of radiation ?

  • @HOUNDF0X No because the frequency of operation is low with respect to the size of the coils their radiation (radiation resistance if you prefer) is quite small. Put simply they are not very good antennas. The energy exchange happens in the "non-radiative" near-field. The near-field is essentially the energy that the would otherwise be recovered as back EMF when you discharge the inductance again. The receiving inductor couples to this field and extracts some of it.

  • I wish I understood this

  • Hello Alan, thank you for your excellent explanations. I just want to point out an error concerning the induced emf: it's not symmetrical to the time derivative of the field, but to the time derivative of the magnetic flux (in fact, otherwise, you'd be hard put to say where the field was calculated!).

  • @hexphreak Indeed, you are correct. EMF is caused by dPhi/dt and flux (Phi) is the integral of B over some area. You need to specify an area to define the flux. This and a whole bunch of complications about H and other details I left out, please forgive my lack of rigour... EMF is still proportional to the rate of change of "the field" (given an specific area) - but it is rather meaningless to only say that, it tells you nothing about what particular part of the field you are talking about.

  • Very interesting.

    Thank you for sharing.

  • muchas gracias por esta informacion, es buenisima.

    thank you for this information, its very good !!!

    =)

  • Awesome

    

  • This is a really great video. Thanks for sharing

  • That is very good mate, and your site is also very good.

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