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need help with flyback transformer

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

  1. lev77

    lev77 New Member

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    transistor

    can some one check if this is connected ok
    an how to connect all this in that secret diogram
    thanks
    lev77
     

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  2. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Hi, Lev77. It is difficult to tell what all you have connected, but all of the bases should be connected together, all of the collectors should be connected (It looks like you already did that), and all of the emitters should be connected. You are basically building one large transistor out of 4 smaller ones.
     
    Last edited: Mar 28, 2011
  3. lev77

    lev77 New Member

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    this is how they all connected.... is this the way they have to be?
     

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  4. dave

    Dave New Member

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  5. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    No. The bases and emitters should not be connected together at all. Connect each base to each base. Period. Then connect each emitter to each emitter. Period. Then finally, connect each collector to each collector. Period. Does that make sense now?
    I just need to ask--Have you had ANY previous experience with electronics? Do you know what the transistor does and which pin does what?
     
  6. Dr_Doggy

    Dr_Doggy Well-Known Member

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    HI, lev, in your diagram you have created a "Darlington Pair" this is for if you have 2 small gain transistors and need to multiply boost that gain. this is not what you want........

    the way DERSTROM says to wire is in a parallel config,, the reason for this is you have enough gain, but you need to split the current between all 4 transistors evenly....so they dissipate heat evenly......
     
  7. lev77

    lev77 New Member

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    Hi dersrom
    no i dont have any experience inelectronics and need get engry.. Thanks all ur help do. Thats why im here try learn it. It takes time but i will get there :)
     
  8. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Hi, lev77. Don't worry, I am not angry. I just needed to know a bit about your background.

    The way a transistor works is this: Think of it as a water tap, but for electricity. You have your supply pipes and you have your tap. To make water flow from the supply pipes through the tap, you have to put a bit of "pressure" on the handle of the tap. This is basically how a transistor works. Your supply pipes are similar to your transistor's collector, the tap is like your emitter, and the handle is your base. To allow electricity to flow between the collector and emitter, you must put a voltage (electrical pressure) on the "handle," or your base. So, to "turn on" your transistor (connecting collector to emitter) just put a bit of voltage on the base.
    Does this help?
    Der Strom
     
  9. unclejed613

    unclejed613 Well-Known Member

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    i'm still teetering on giving a WILE E. COYOTE award on this one.... but i'm holding back. when i was young and learning electronics, i had some "wow it would be cool to..." projects myself. i didn't have the luxury of learning "how to" from a potential pool of thousands of people from around the world. but my grandfather taught me what he knew. a lot of it was "keep one hand in your pocket while working on live circuits", and how to solder, and how a tube works, what the basic components do. another thing he taught me is that if you have a project and you can't make it work, or you have a hard time understanding what's going on inside it, put it aside, keep working on understanding it, and build other projects using some related principals until you get to where you can build that one and make it work. "Rome wasn't built in a day" was what he said when i got impatient.... i also had a boss early on that always said "if you don't know what you're doing, don't" and i would add to that "build from the ground up", learn what the components do, learn how they interact, learn the basic circuits (RC time constants, series resonant LC circuits, the three transistor amplifier circuits, etc...), and begin building on that knowledge and gaining experience. Rome wasn't built in a day, and your project might not be, but when you build it you will know what makes it tick. i'm sure all of us here would also like to see you survive the experience with all of your fingers intact too....

    in case you're wondering what a Wile E. Coyote Award is, it's on my blog on this forum here http://www.electro-tech-online.com/...ew-award-wile-e-coyote-supergenius-award.html
     
  10. Dr_Doggy

    Dr_Doggy Well-Known Member

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    LEV, charging up a cap is simple, put the gnd terminal to gnd, and put the + terminal to the flyback, let it run for a second to charge, then even after you turn off the flyback the cap will still be charged, so take another ground wire and touch it to the +side to discharge it! (get ready for a bang!)

    I used 1uF @ 4KV capacitor before i was satisfied, but make sure the cap can handle the voltage

    BEWARE OF HV yayaya, touching a charged cap will zap you good, USE PROPER INSULATION GLOVES.
     
  11. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Proper insulation gloves for that kind of voltage aren't sold on retail. The type you would need are what linesmen use, and probably cost a few hundred U.S. dollars a pair. Not exactly easy to get a hold of. I would recommend just not going anywhere near the cap, and to discharge it by shorting the contacts with a long, well-insulated plastic pole. That's probably the safest way you'll find.
    Der Strom

    P.S. Just to warn you again, the charge stored in that capacitor could blow your fingers or hand clear off if you're not careful. DO NOT, BY ANY MEANS, COME IN CONTACT WITH THE CHARGED CAPACITOR!!!
     

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