This instructable will show you how to make a cheap and simple driver circuit in order to get high voltage arcs out of a component called a flyback transformer.
A flyback transformer, sometimes called a line output transformer are used in older CRT TV's and computer monitors to produce the high voltage needed to power the CRT and electron gun. They also have other auxiliary windings built into them that the TV manufacturers use to power other parts of the TV, so they are usually customised by the manufacturers.
For the high voltage experimenter they are used to make high voltage arcs, which is what this instructable will show you how to do with just a few simple electronic components.
You can get flyback transformers out of older CRT monitors and TV's. They are the ones that have a big heavy chassis. There are also other instructables on this website showing how to remove them from the chassis and circuit board.
Disclaimer
I am in no way responsible if you mess up with this circuit. If you mess up you have no one to blame but yourself.
What you will need:
1x Flyback transformer
1x 2n3055 transistor + heatsink
1x 220 ohm 5 watt resistor
1x 22 ohm 2 watt resistor
(Note: The resistor values do not have to be exact. Say if you had a 33 ohm and a 200 ohm resistor they would still work fine for this circuit).
Some enamelled magnet wire, single core bell wire also works well too for the primary and feedback coils.
A fast diode. Although this is not needed for the circuit to work, it protects the transistor from back emf spikes and can help prolong the life of the circuit. I just used the one I found on the TV board but the UF4007 is an easy one to get hold of in electronic stores if you need to buy one.
+Some way of connecting the components
such as alligator clipped cables or wire and solder.
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Signing UpStep 1Mount the transistor onto the heat sink
Mount the transistor onto the heat sink. The heatsink is important as the transistor gets hot. I just bought the cheapest heatsink maplin sell. The 2n3055 is a TO-3 case style.
You can use an insulator pad if you want but I just used a small amount of old thermal grease I had lying around. To mount the transistor to the heatsink I just used some spare screws and nuts I had in the garage.
Make sure that the transistor pins do not physically touch the heatsink and it is screwed in securely.
Q: Can I use a different transistor?
A: Yes you can, as long as the transistor has similar specs to the 2n3055 or better.
Q: Can I use a PNP transistor?
A: Yes, but you will have to reverse the collector and emitter connections in order for it to work. It will also need to have similar or higher specs as the 2n3055 transistor.
Q: Is the heatsink really needed?
A: Yes, if you are wanting to use this circuit for more than a few seconds the heatsink is vital as the transistor will get hot fast.
Q: Can I use a MOSFET?
A: No, a MOSFET will not work for this circuit.
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I estimate there is no more than 900v-1kV here but there must be around 800mA-1amp in the arc.
Gene
All the magnet wire I have purchased from my local electrical store has required me to scrape off the enamel before soldering. Even with my coil gun project where I was using voltages of around 300V with the magnet wire I still had to scrap off the enamel in order for any current to start flowing.
Maybe someone here knows what kind of trouble?
Thank you
I have made the 555 based driver myself and have also audio modulated it here http://www.instructables.com/id/555-timer-based-plasma-speaker/
But I have also found that the MOSFET's and the NE555 chip tend to die easily in that set up. If you know a way of keeping the NE555 and MOSFET's from dieing then let me know ( :
Try connecting one (in parallel to the supply) anode to the minus of the supply.
This should take the current from the main coil during switch off and prevent overloading the FETs .
Can you send me a link to the schematic you followed?
I have made the ZVS driver and it works very well. I can get 3 inch hot arcs on 24v input. Its definatly a must try if you are into this sort of thing ( :
thx
You would need to wire it up backwards though as it is PNP.
This can kill you if you don't know what surfaces you can/can't touch.
Even if the equipment is off and unplugged the charge stored can be lethal for a very long time. It's a big capacitor.
This step is attempting to describe how to drain this charge so you can work safely. You must connect the high voltage to ground THROUGH a small resistance to avoid welding your probe to the terminal.
Use Ohm's law to calculate how long it will take the voltage to drain through your resistor and how high a wattage rating your resistor needs to be.
If any of this confuses you.
STOP!
This level of electronics is above your head.
Go back to the books to understand fully what you intend to do with electricity.
You do not need a resistor, this is not a capacitor bank and it will not "weld" bits of metal together.
Have you actually made this circuit? It outputs very little current on the high voltage side, below 1mA.
I have done this many times for fun.