Connect with us

PCB Induction Charger

Discussion in 'General Electronics Discussion' started by J22L, Jan 24, 2013.

Scroll to continue with content
  1. J22L

    J22L

    17
    0
    Jan 24, 2013
    Yes, but will this design work?

    None of the measurements are exact and my actual design will include many more turns, but I just made the picture quickly to explain what I mean.
     

    Attached Files:

  2. davenn

    davenn Moderator

    13,866
    1,957
    Sep 5, 2009
    ummm the link doesnt tell us how much signal level the generator produces and I
    couldnt find any other info for it
    does the unit have written on it what its output level is ?

    I would suspect only a Volt or so maximum which wont really be enough to do what you require, you would have to amplify that signal

    Dave
     
  3. J22L

    J22L

    17
    0
    Jan 24, 2013
    I will see if I can find more information on it.

    Thanks.
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,497
    2,839
    Jan 21, 2010
    (This is in response to post #19)

    Yes, your original circuit is completely wrong.

    Notice how one coil (from the outside to the inside goes clockwise, and the other one goes anticlockwise.

    Your best bet is to have one coil going from the outside to the inside on one side of the board, raking the ends (outside and inside) and applying power to them.

    If you have double sided board, then you can place one coil on each side, and connect the centers together (through a hole in the board).

    If you look at the way the current needs to flow, it will go round and round and round as it goes from one edge to the middle, then cross over and go round and round as it makes its way back to the edge. The thing is, the coils will be mirror images of each other. the current needs to be going around an imaginary axis through your board in the same direction. If it goes one way then the other, the effects cancel out.

    In your diagram above, both coils go anticlockwise, but the current in one is the opposite direction to the other, So the current starts out going anticlockwise as it moves to the center, then goes clockwise on the way back out.
     
  5. J22L

    J22L

    17
    0
    Jan 24, 2013
    How can I make a design for just a one-sided PCB? Could you show me a sample design?

    Thanks.
     
  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,497
    2,839
    Jan 21, 2010
    The one in your post 21 is fine.
     
  7. J22L

    J22L

    17
    0
    Jan 24, 2013
    Great! How many turns do you recommend?
     
  8. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,497
    2,839
    Jan 21, 2010
    Anything between several hundred and several thousand (if you're using 50Hz).

    You still haven't answered my question about the signal source
     
  9. J22L

    J22L

    17
    0
    Jan 24, 2013
    The device does not say anything about the signal source. I don't know if it helps, but it is powered by a 9V power supply.
     
  10. davenn

    davenn Moderator

    13,866
    1,957
    Sep 5, 2009
    that was answered in post #18

    a Wavetek Function Generator 30 but we dont know what its output is

    Dave
     
  11. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,497
    2,839
    Jan 21, 2010
    If it's just a function generator, he might be able to get enough power to light a LED I guess.
     
  12. J22L

    J22L

    17
    0
    Jan 24, 2013
    I am not actually using my boards to charge anything, I just want to input a signal and put my other board on top of it attached to a voltmeter and see some numbers to show that they are transmitting power. So will the Wavetek work for my purpose?
     
  13. BobK

    BobK

    7,682
    1,688
    Jan 5, 2010
    Well, if you put a 50Hz signal into the inductor you are talking about, it will pretty much look like a short circuit, so I'm not sure what the signal generator will do with that. You should use the highest frequency the generator can produce, then there is a chance it will develop some voltage.

    Bob
     
  14. BobK

    BobK

    7,682
    1,688
    Jan 5, 2010
    Okay, I did some calculating for you:

    It looks to me like your board is abouut 50cm square with the traces being about 1mm spaced about 1mm with 12 turns in the spiral. This caluclates out (thanks Harald) to a whopping 3.5uH.

    At 50Hz this has an impedance of 0.001 Ohms.

    At 200KHz (the highest your signal gen goes) it is 4.4 Ohms.

    Your signal generator is not likely to drive much power into even the 4.4 Ohm load.

    I also calculate a 4 in square boad with 0.01 in traces 0.01 in appart for 100 turns. This comes out to a more reasonable 400uH. There you might be able to get something with it presenting a reasonable load of 50 Ohms at 20KHz.

    Bob
     
  15. J22L

    J22L

    17
    0
    Jan 24, 2013
    Hi, thank you for your calculations. I am getting started designing a board that meets those specifications. Do you think you could tell me the formulas you used to calculate everything?

    Thank you.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-