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!
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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Signing UpStep 1: 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. :-)
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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built this circuit and when i first plugged in a 9v battery, i could hear the high pitch from the flyback.. consequently though I didnt see any arcs and the high pitch tone changed when i tried touching the ground output from the flyback to the positive output. Randomly though the circuit suddenly worked and i saw some nice arcs, but a bit later the circuit was doing the same thing as before. does someone know whats happening?
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.
as you can see the half cycle is 1microsecond which means 500khz frequency
the problem now is that I do not get high voltage on the flyback
as far as I know the ferrite core goes up to 2MHz, may the problem be the capacitor which can not handle big currents so I will try a more powerfull capacitor
the diode may be another problem because it's not ultrafast
the FET is ok according to the datasheet for this frequency
When you start up the oscillator and before arching you should hear the 10khz sound.
If not then the oscillator has not started up and this means that on of the FETs is constantly ON and it will heat up to destruction within seconds.
This type of oscillator for some reason does not always starts up so you must stop the power supply immediately and start it again. This happens more often when you give low voltages, for example if you power it with 5 volts it's very difficult to get it oscillating but it is possible.
I managed to melt the case of the FET although I used heat sinks within seconds but the FET is OK.
I will device some method to be sure that the circuit will oscillate 100% if it is powered up.
the distance at which an arc can start-up strongly depends on the shape and the capacity of the electrodes
as you can see I have used two wood screws for not damaging the pins when they reach incadescence. between the tips of screws the arc starts nearly in contact only. between the bodies of the screws the arc starts at about 1cm.
I will use various other geometries as well as the Wimshurst machine electrodes which are spheres.
Conserning the sound you may hear when not arching, this happens beacause as you can see from the graphs the frequency reduces to one-fifth of the one when arching, which means that goes down to 10KHz, this frequency goes back to the power supply making the power supply to vibrate in this frequency which is an acoustic one.
I suggest that you don't run the ZVS without arching or anyway loading it some way.
I attach two photos and two oscilloscope graphs of the two FETs. I used both channels of the oscilloscope, one for each drain of the FETs.
The low frequency and higher voltage graph is valid when there is no load/no arching on the flyback
When the flyback arches then the frequency increases and the voltage drops as you can see on the respective graph.
The destortion while the FETs go on and of may have to do with the diodes, I will try faster ones than the FR207.
I attach two photos and two oscilloscope graphs of the two FETs. I used both channels of the oscilloscope, one for each drain of the FETs.
The low frequency and higher voltage graph is valid when there is no load/no arching on the flyback
When the flyback arches then the frequency increases and the voltage drops as you can see on the respective graph.
The destortion while the FETs go on and of may have to do with the diodes, I will try faster ones than the FR207.
Even this "simple" circuit has a realm of parametres, practice is much more than theory
Just think that this circuit in theory does not oscillate!!!!
My power source is an old AT computer supply from which I get the 12volts (yellow-black cables)
Certainly you should not run your oscillator without some kind of load on the flyback or without arching, the energy is stored in the circuit and I guess it will explode. The soynd that you can hear is some part of the circuit that oscillates in a frequency that you can hear.
I attach the image from the USB oscilloscope DSO-2090, this is the graph of the potential between the ground(source) and the drain of the one of the FETs.
As we can see the one FET is ON for about 10 microsecnods(100KHz) so a full cycle is 50KHz.
The voltage width of the oscillation is about 25 volts that is two times the source voltage.
it's 100% solder free
the flyback is a very old transformer and you can see the its box, I found at the local store for 2 euros
the whole project cost about 15 euros
the FET are IRF540N pin1 gate, pin2 drain, pin3 source
I didn't yet checked the frequency
the capacitor is MKP visaton 1microfarad
the fast diodes are FR207 alternatively you can use BY299 or the SF and HER series
FR207 switches in less than 500 nanoseconds according to the data sheet while UF4007 gives 75nanoseconds max. For our frequencies 500ns is ok
All these in Greece
This site (http://lifters.online.fr/lifters/labhvps/tht.htm) says "With a simple ohmeter this is very simple, you will find easily the primary inputs because the coil resistance is about 1 ohm"
I bought a new flyback a couple of weeks ago. My flyback has 10 pins. I got these results:
Pins ..... Resistance
1 + 5 .... 2 ohms
1 + 9 .... 1.8 ohms
5 + 9 .... 0.9 ohms
2 + 8 .... 0.9 ohms
3 + 4 .... 0.8 ohms
3 + 6 .... 0.8 ohms
4 + 6 .... 0.6 ohms
All the other combinations (i.e; pins 1 + 3) produced no resistance, so that means that pins 1 + 3 are not connected. Conversely, this means that pins 1+5+9 are connected; pins 2+8 are connected; pins 3+4+6 are connected; and pin 7 and pin 10 are not connected to any other pins.
The first problem is that many of these gave me a resistance close to 1 ohm, so I still don't know which pins to use for the primary coil.
The second problem is that a flyback should have two sets of connected pins; pins that connect to the primary coil, and pins the connect to the secondary coil. However, I seem to have 3 sets of connected pins (or five sets, depending on how you count). Does this mean something is disconnected inside my flyback?
I didn't know what to do, so I just went ahead and connected it to the CFL circuit. I tried pins 5+9, 2+8, and 3+4 as the pins to the primary coil, along with every combination of the 4 pins on the CFL circuit, but did not get a single arc for any of them. Does this mean that my brand-new flyback is bad?
Cheers all for any input you provide :)
The answer's regarding accelerated Ion flow are the more correct answers tho, given the HV field being generated.
Quick question tho, I built one of these with IRF450's, fired it up and got nothing. I now know that the input inductor I wound is FAR too large but, are you supposed to remove the air gap from the core of the flyback? or does it need the air gap to "fire"
cheers.