Flyback Driver Circuit.





Introduction: Flyback Driver Circuit.

This is a instructable that contains scematic and pictures of a single transistor flyback driver.

stuff's used:

1x breadboard
1x NPN transistor (with heat sink and a fan)
1x 22 Ohm resistor
1x 220 Ohms resistor
1x transformator (or round ferrite core) with same amount of windings
1x flyback transformator
1x 12 - 15V Powersupply ( i use a battery that gives 15 volt, 400 mA)

And some wires.

Step 1: Scematic of the Driver

After i tryed the flyback driver with the primary and feedback windings on the flyback's ferrite core, i thought: *why not try t o use a tiny transformator with same amount of windings to oscillate the process, and so i found out i would try it, and i got 10 - 15Kv More from the flyback transformator by doing this, so i figured i would make an instructable.

i think the picture is somewhat blurry cause of the size, so il point out the important stuffs here:

* The transistor must have a heat sink.

* Before you put 12 volt in, test the circuit with 3 - 6 volts, and make shure that the transistor doesn't get overheated
(I currently run the circuit with 15 V , 400 mA, and still i cannot feel any sign of heat on the transistor)

i get around 50 Kv from this.

If you have any questions, just ask.

Step 2: Pictures & Setup

Here you can see my setup.

Step 3: Sparks



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    if you want to simplify the schematic:

    flyback driver.png

    I have now updated the scematic my wookie.

    why do I need resistors? if I have the right power supply can I skip the resistors?

    No =) resistor's is good, you should use them, we are only using interference to turn the transistor on and off, it would not improve anything not using resistors, only hurt or burn your transistor. (as i think the transistor gets fully saturated anyway, you could do some math on voltage dividers and transistors).

    Thanks =)
    True ! simple is good! =) (y)

    just a tip, if your transistor heats up high, chances are you need higher ohm resistors

    Very cool. I'll have to try this as soon as I can find a heat sink mounting kit for my transistors.

    So basically you found that a 1:1 transformer acts like a feedback so you have now an external feedback to drive your transistor but how does this improve it ? is-int the feedback in the FBT good enough? also are you using the primary of the FBT or did you wind your own? I have found that if you put a wire between the return and the wire that goes to the voltage divider it improves the arc also another discovery I made to drastically improve your arcs( brighter, bigger, longer,louder) is to hook up a capacitor in parallel between your output wires I made a small simple homemade one and am now getting about 90kv.

    hooking a capacitor across the output should only give Fatter thicker sparks not longer I believe.. really strange if you got longer sparks are you sure?

    i didnt get longer sparks, just loud and strong.
    i made a capacitor from a bottle of salt in water solution, + aluminium foil on the outside, powerfull, not that long lasting though.