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need help with flyback transformer

Discussion in 'Repairing Electronics' started by lev77, Feb 15, 2011.

  1. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Hi, lev77. Overall this looks pretty good. Now that I think about it, though, you may want another resistor across the first diode as well. I didn't really think about that before....
    You also need to make sure all your diodes are in the right way. If you have one of them backwards, you risk the rest of your diodes, your resistors, and your output. Make sure they are all connected facing the correct direction.
     
  2. lev77

    lev77 New Member

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    hi DerStrom
    i will add another one. all the rest is as u told me they all face right way..
    the IN and OUT r they on right direction? IN (-) the one with the line yes..
     
  3. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    In order to tell which end is the cathode and which is the anode, you will have to look at the diode datasheets that you can easily find on google. I'm not sure if I understand quite what you are saying, but IN should be the "back" of the diode (furthest from the band). Here's a rough diagram:

    IN ----l>|----OUT (band is on the right).

    Does this make sense?
     
    Last edited: Mar 21, 2011
  4. dave

    Dave New Member

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  5. lev77

    lev77 New Member

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    this is a close up one just check if its all good
    thanks
    lev 77
     

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  6. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Okay, the diodes are all facing the same direction, but IN should be at the "back" of the diode (see my previous post). You just have your "IN" and "OUT" backwards.
     
  7. lev77

    lev77 New Member

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    ohh ok ill change them thanks..
    other ways all good ye..
     
  8. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Yes, it appears so. All you have to do is make the change that I have posted below:

    Rectifier.jpg
     
  9. lev77

    lev77 New Member

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    cool cool thanks mate for ur help
    Wednesday ill tray it. will see how i go.. ill let u know...
    lev 77
     
  10. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Great. You do that :)
     
  11. unclejed613

    unclejed613 Well-Known Member

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    after looking at the pics, let me give you a hint about soldering for high voltage. it's a bit different than low voltage soldering. high voltage soldering requires "blob" soldering. sharp points and angles are a no-no. with round blobs, air bubbles, rough spots and inclusions are also a no-no. the idea is to minimize corona discharge from bleeding energy from the circuit
     
  12. shokjok

    shokjok Member

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    I haven't tried to use a TV flyback in an automobile ignition circuit. I don't know if the rectifier will diminish the output voltage, or cause unpredictable results. Have you tried the website address printed on the label?
     
  13. lev77

    lev77 New Member

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    No luck :(
    it didnt work.. with the rectifier it didnt charge the cap at all. the was no sparks coming out of it. with out of it the was more sparks from car coil then with it....
    ill try to get proper rectifier this time.
    thanks all for u help.. :):)
    lev77
     
  14. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    I guess I'm not quite sure what you are expecting to happen. A photo of your entire setup would be very helpful. That way, we could see if you may have connected something wrong. Any chance of posting a picture?
     
  15. lev77

    lev77 New Member

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    this is the pic .....
     

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  16. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    I don't see the driver circuit for your ignition coil. Where is it?
     
  17. lev77

    lev77 New Member

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    its behind the car battery
     
  18. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Oh, okay. Would you happen to have a schematic of your connections? In the photo I see a bunch of wires but can't quite see where they go. Sorry about all the demands--It's just somewhat difficult to follow what you're doing :D
    Der Strom
     
  19. unclejed613

    unclejed613 Well-Known Member

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    even with an effective driver circuit, it will take a while to charge that cap up....

    what are you using to drive the coil with?
    i saw the circuit you had, but that requires a pulse input (like a 2khz square wave... 2khz because that's the approximate resonant frequency for an ignition coil(i know this how???? i've driven ignition coils with amplifiers to use as a crude ionophone)) to pulse the coil continuously...
     
    Last edited: Mar 24, 2011
  20. lev77

    lev77 New Member

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    thats the driver im using.. so how do i get that 2khz square wave pulse input????
    thanks
    lev77
     
  21. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    If what unclejed613 said is true (I'm not doubting you, unclejed) then you would probably want a simple 555 timer circuit. A 555 timer is able to create a square wave output from a steady DC input, and it should be easy to set one up in astable mode to produce one of 2khz. Here's the circuit for an astable 555 timer:
    [​IMG]
    R1, R2, and C1 determine the output frequency. I hope this helps!
    Der Strom
     

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