How To Build A Simple But Powerful Flyback Driver

Picture of How To Build A Simple But Powerful Flyback Driver
Tired of little purple sparks? Want bigger hotter sparks? Then try: 

The ZVS Flyback Driver

It is probably the most powerful and efficient flyback transformer driver that was fairly recently invented by Vladmiro Mazilli. It uses resonant zero voltage switching (also know as ZVS) to drive the flyback transformer. This means the MOSFET's are designed to switch (on or off) when the voltage across them becomes zero.

Because the MOSFET's switches when there is no voltage across them, it will generate very little heat, the only source of heat is caused by the MOSFET's internal resistance. Unlike the simple 555 timer flyback drivers, The ZVS flyback drivers will allow you to run your flyback transformers for much longer periods of time before the MOSFET's overheat. If you get really good MOSFET's, it might be even possible to run your ZVS flyback driver infinitely! (Or until the circuit is interrupted)

Video of it working! 

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Step 1: The dangers of the ZVS flyback drivers

Picture of The dangers of the ZVS flyback drivers
Not only the ZVS flyback driver is powerful, but it is very dangerous. You can easily pump several hundreds of watts into the flyback transformer and the output current would be around 50mA to 200mA (or even more), which is way above the lethal rate which is 10mA.

Do NOT attempt to do this as your first flyback transformer driver project, I recommend you to start with using simple 555 timer flyback drivers before thinking about building an ZVS driver.

And finally, you are solely responsible for any harm to others or damage or any other problems that a ZVS driver may cause. The ZVS driver should be used for educational and research purpose only.

That is the end of my health and safety rant. :-)
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What is the voltage of this thing roughly?

AhmadM1118 days ago

Finally I made it!

But something just feels not right.. The stream from flyback transformer always try to breach anything to find ground.. And mostly it did it in one way or another, every time I move the cathode away.. Once the stream lost, it's like going wild.. Sometimes I can see sparks outside the fuse case of the DC PSU..

I drive it from a 10A 36VDC PSU.. I doubled the 2W resistors value and increase the zener to 24V also two 270nf/400V caps in parallel as the final caps..

I've been questioning what could be wrong with the circuit.. Or is it just because the voltage too high for my entire circuit/case design? Because it still can reach my hand through my 50cm PVC chicken-stick.. I can feel it and I can clearly see a slight stream strike back to the PVC.. Kinda strange for me because a PVC should be a good insulator..

move the power supply away from the driver and the driver away from the transformer (increase the length of the wires) that would work also try using insulating tape on your chicken stick.

shigeno211 month ago

is it possible for a hog stunner? how could i increase the current ?

Why would you want to stun a hog.....

it is my project for a backyard slaughter house i think a minimum amp to stun a hog is 1.25 amp can i use a microwave transformer rather than a flyback transformer of tv? can you help me thanks in advance.

1.25 amps, how many volts, what is the power in watts?

hmm around 220-250V so i think it will have a 275-320W from a minimum of 1.25A

Mains current unless you are hunting then lithium batteries connected to an inverter, this is hundreds of thousands of volts.

dillonxti9 months ago
I need a version where you don't need zener diodes and you can use the wall voltage to power it
I meant I may need a version where you don't need zener diodes and you can power it straight from the wall voltage

Dude,i''ll give you a hint, if you just want to power up your flyback you can modify a power supply, just fking remove the original transformer, find the primary winding using a multimeter, and weld the old pcb to your transformer. Weld a simple diode (IN4007 or other) in parallel with the output of the optocoupler to assure that the driver will work in maximum charge, and voilá.

It took me 20 minutes to weld the whole thing and make the new turns on the primary of the flyback. **i used 100 turns.

I actually made it work without the diodes and transformer my autospell kept putting need instead of made so yeah it did that to me twice

Could you send us a schematic?

the circuit on the left is my schematic the one on the right is the original -video of it driving a Tesla coil:

Thanks, got the instructable circuit to work though, the flyback transformer is

Nice instruct able but I am facing some issues, my mosfets and inductor just heat up and it does nothing else, is there something wrong with the circuit or the mosfets or the inductor or the flyback transformer? Any valid help would be of great use :D

My flyback transformer is spoilt, its still outputing 18-19 volts AC

Yeah that was the only problem.

ybaggi8 months ago

Very cool.

do these arcs and sparks have any useful domestic or industrial application?

or is this all just for fun?

Making ozone

And what is Ozon good or useful for?

Disinfecting fruits/vegetables, but you have to dissolve it in water first, its also a strong oxidising agent but it is a free radical so try not to breathe it in too much.

TK1756721 year ago

Thinking of building this and i wanted to use a computer PSU but i wanted to ask: if i just connect it won't it try to draw the map amps the PSU can give and and possible damage the PSU or will it be fine? would i have to limit it in some way?

I tried using a PSU, it provides approximately the current required but I think there is something wrong with my circuit.

z0tx4 years ago
I'm trying to build one of these, and this tutorial is excellent, I have one question: Will a couple of batteries in series be suitable for the power supply?

Yeah he used it himself

AhmadM1126 days ago

Is this crcuit can be used as a power supply for electrolysis? Regarding the "visible" amperage that seen in the process when it melts a metal..

Actually I've made a circuit similar to this driver with couple adjustments like 3 turns(not five) in the feedback coil and dual parallel common 274J-400V-MPP as the final capacitor (Pardon my english)

fatevian2 years ago
Hi everybody!
Someone can clear me a doubt?
It works if I put a HV diode to rectify? Do you think it's possible with this circuit, to supply high voltage to magnetron oven? What do you think?The current is strong enough to break down the barrier of diode?Thanks.
I doubt it. The voltage is too high and current is too low. MOTs output much more current than this. Also, most microwaves are around 1000 watts, and this ZVS only has 400 watt input.
a good zvs can resonate a good thousand or two amps at 300 volts well at least that is what mine did with wall voltage
mcrenno217 months ago
Do the math to find your output voltage,
Output amps= .02-.7 amps
1:135 flyback ratio base on internal winding
turns 5+5 turns
input voltage ??? Depends on you,
my zvs
input 28v
output 63000v
I2 26mA
turns 6+6
20141110_190028.mp4(240x320) 10 KB
_Totoro_ made it!10 months ago

Great driver and 'ible! barely gets warm at 12v coming out of a PC PSU and really nice arcs, modifying a Microwave Transformer soon for 24v for longer arcs. Fiddling with the capacitor value helps a lot to get the best out of your flyback. I ended up with an arrangement of 6 caps (1µf 275v), 3 pairs in parallel then those 3 pairs in series to achieve 0.66µf capacitance that has a rating of 825v which meant less capacitor heat and easier to modify the frequency with different arrangements, this the is the calculator i used for the capacitor arrangements

danmellow10 months ago

osum stuff mate... nailed it

Fastestone010111 months ago

i found my Fathers old TV repair stuff in the shop the other day, and i've found several caps that are in there that are in there that are around 40+/- Mfd

dudes11 months ago
get the irfp250's from they are only $1:50 each. and very low shipping
dudes12 months ago
any idea on the voltage that this puts out? after the flyback.

Can somebody explain me what comes out of that 3 terminals? (where the coils are attached). How much current or voltage? what kind of wave? why two different coils are needed?

is there a way to make it not lethal

Some common safety rules/procedures I have read are: Keep one hand in your pocket whenever the device is powered on. Always wear safety glasses. Place the device as far from the edge of your bench as you can and still handle it (In case it slips off the edge when powered up.) Keep an extinguisher rated for electrical fires nearby. Do NOT place the circuit anywhere near metal flashing or framing, etc. Put it on a dry insulating surface. Put yourself on similar material (Eg. rubber mat, plywood sheet.)

When possible use opto-isolators to connect low-voltage signal lines to the rest of circuitry, esp. when you are touching the low voltage controls. Separate the high and low voltage circuit components with a grounded metal cage or barrier of some sort. Obviously, the cage has to be large enough so that it's walls are not going to short out to the HV inside it. For HV outputs use wire rated for twice the voltage you are delivering with it. (All capacitors should be rated similarly; they can explode dramatically.) Take into consideration the current rating for the gauge wire you are using; you don't want the wire to melt or catch fire. Don't use cheap auto ignition wire for this purpose. Use genuine HV wire that has thick insulation. Silicone insulation should be more flexible than PVC. If you must handle the HV wires, use with rods of wood, rubber, plastic etc. Don't trust ordinary screwdrivers and pliers, no matter how much rubber coating is used on the handles. Use common sense. With these requirements in mind check everything twice before powering up.

I make no promises that this list is complete. Use common sense.

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