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16th February 2012 10:15
please,
i need the equation of solenoid coil inductance that you use , cause every calculator on internet or any formula doesn't give me the values you wrote in the picture.
and i need also all the expressions used for the generated field and received current and voltage as in that range of frequencies the circuit's behavior follows RF analysis not magnetic analysis coupling
thanks in advance.
waiting for your reply
24th January 2012 17:03
Hi alan
I'm halfway through the design.. There is no availability of cap inductor near my place.. Can u suggest me an alternative component instead of cap inductor..
3rd January 2012 06:13
Hey There smart professor :)
I am a student from Bonaire, The Netherlands Antillen.
Kind in need of your help. We got stuck in our project. We couldn't build a working wireless transfer demo to show our classmates.
Please reply me asap. Would be so grateful if you can do it before 7th Jan.
I need your help of giving me a guide to build a small scale demo to show my classmate this wireless power technique.
and would really nice if you can give a description of each of the materials what they are for and why.
7th December 2011 13:42
Hi Alan,
I built the exact same circuit you have as I am doing a study on wireless power transfer. I am not sure where I would be going wrong but I cant seem to get it to work. What is the average voltage I am looking at by the coil.Is there a way I can send you a picture of my circuit and you could take a look at to see what I am doing incorrectly. Appreciate any help you can provide. I used the same values you have for the circuit.
14th October 2011 03:05
Hi,
There's something that I don't understand :
Receiver is composed by capacitor and coil inductance where values give a resonant frequency of about 14Mhz so same than your quartz. But how do you choose values of capa and coil in the emitter part ?
Thx in advance for answer
23rd September 2011 16:35
Hi Alan,
I am currently working on a project along the line of wireless power transfer. Your demo has proved to be a real help. However, i am unsure about certain concepts such as the power being transferred by the transmitter and the received power. If i were to transmit 10W, does it depend on the class E amplifier? Any directions would be a great help. Thanks.
Best Regards,
Deren
25th August 2011 04:15
For Kenneth,
Hint, I've run ~25W at a lower frequency with a similar circuit using ferrite cores to direct the flux into more useable patterns over 1/4 to 1/2 inch gap. The driving circuit was a bit more complex (Add PWM and frequency control), but basically the same idea.
Dan
3rd July 2011 21:16
Anna,
The oscillator is a canned "14 pin style" TTL 14.91 MHz square-wave oscillator module. It actually only has 4 pins, two for power, one not connected, and the other signal out. It runs from about 5 volts and delivers nearly 5 v peak-to-peak into an open circuit.
They are very common and many frequencies are available. I used this one because I have a few in the junkbox, it is not a critical frequency at all, any HF one should work, from a few MHz to 20 or so. Of course my tuned circuits were optimised for ~ 15 MHz.
If you really can't find any, I have plenty, I can send you one.
Regards,
Alan
3rd July 2011 21:13
Rodrigo,
Unfortunately I do not speak Spanish, but I translated your message using Google Translate.
5 Watts, shouldn't be too difficult, especially over short range. I'd be interested to see how it turns out.
Regards,
Alan
3rd July 2011 18:24
Kenneth,
Are you running the complete system at resonance?
The efficiency will be really poor if both sides aren't resonant or have poor Q. You don't mention capacitors, so measure the inductances on both sides and add capacitors to tune the system to resonance at the frequency the 555 is running at.
Regards,
Alan
22nd June 2011 14:04
what is the oscillator can give me details of the crystal oscillator
19th June 2011 16:08
Hola Alan
Exelente la informacion disponibles, demasiado buena. Estoy en estos momentos en un proyecto en U, en donde como meta nos propusimos, transferir 5 Watt de potencia.
La verdad que me gustaria mucho pedirte si tienes algo en español, como por ejemplo tu video, o algo asi. Me gusta mucho el tema y quiero partir bien del principio.
Nuevamente te fecilito por la pagina, y ojala me puedas responder.
Saludos
28th May 2011 13:34
Hi Alan - I really enjoyed your article. I have a couple of questions please. What is a good source for the 14.910 oscillator and:
I am attempting to build a miniature wireless charger for a 3.7 Vdc, 100 Mah/ 20C, Lipo cell. It's to fit inside a small robotic device that requires wireless charging of the Lipo cell. The receive side coils (size restraint item) I have available are 153 turns of # 38 AWG with a dia of 12mm as part of a LC tank feeding a FWBR. It produces 4Vdc but not enough Ma to barely light a LED. For the TX side, I have used a 555 feeding a npn/pnp pair and that into a LC tank. I have wound 80 turns of # 26 AWG for the TX coil. I am stumped on how to get more current and would ask you for any suggestions on what direction I should try. I would appreciate any response you might be able to provide.
Best Regards
Kenneth Dale Thomas
KH7TU
14th March 2012 08:44
Tamer wrote...