Step 2: Schematics

I got the idea from scopeboy's website on his flyback driver section, but the schematic was quite complex and buying four MOSFET's is a little too expensive for me...

So I simplified the design to using one MOSFET.

I get a lot of complainants of this project is not working very well or at all. This new design WORKs, however, for most people it may not work. This is due to the MOSFET (and some other components) is poor quality.

I just recently found out that manufacture who makes the components sell the best quality ones to other manufactures and sell the poorer quality ones to the whole sellers and retailers. For this project, the best grade MOSFET's is critical, and it can only be gotten by salvaging old electronic devices, unless you are willing to pay for thousands of components for the manufacture... :-)
<p>awesome, great idea.. </p>
<p>Cool! but what's the use of the diode in parallel with the mosfet? </p>
Hi dude! Thats realy work after i use filtered supply. When i use just diode and transformer dond work well.. good intructs!!!
<p>I've built it but I was wondering if you could measure how much current it draws since the power supply that I was using has now passed away ;( RIP Power supply</p>
<p>This seems little bit risky type of thing.</p>
Tesla would be wicked proud.
<p>will a center tap 12-0-12 flyback work?</p>
<p>hey!!!<br>can i convert a tattoo gun into one of these?</p>
<p>So fantastic! But I am a little confused that, the TL494 has 16 pins, where the second and tenth pins go??? Thanks!</p>
<p>In the schematic it says 47nF 2kV which you corrected to be 47uF 250V, but in the parts list it says 47nF 250V, so is it 47uF or 47nF? Thanks</p>
<p>I used 47nF 2kV.</p>
<p>Is there anybody still online? </p>
<p>I like the design and may attempt something similar sometime, however I did notice one thing in the schematic that would perhaps explain why the mosfet was getting so hot. there is no gate to ground resistor, meaning that the gate goes from 12v to 12v and high impedence when it should be going from high to low. the tl494 has an essentially open emitter output to the mosfet, otherwise I like the idea of using dead time control as modulation, very cool. </p>
<p>What's your solution to the heat problem? Just putting a resistor from gate to ground? </p>
<p>Also, read the datasheet for the tl494, it will show that the gate driving pin is an &quot;open source connected transistor&quot; (google it if you want to) and my previous comments will make sense. </p>
<p>There is probable a pull down resistor in the tl494 or the mosfet gate, thus the circuit works in the first place, however the mosfet is probably switching slowly or partially, due to the high driving impedance on a low impedance gate. If the gate to ground resistor doesn't work, try heat sinking the mosfet along with it. I reccommend a resistor value of around 100-1000 ohms, try 1000 first. </p>
<p>the 22k potentiometer controls the duty cycle or the power supplied to the flyback</p>
Dear Plasmana, <br> <br>I used my plasmaspeaker for over a year now but I have a problem. <br>I always used a laptop power supply (90 watt) for the flyback transformer and last week I bought a heavyduty power supply (50 volt/16 amps, 800VA) and now I killed my MOSFET (IRF640). My question is; wich MOSFET can I use for pulling a few hundred watts without killing it. The max the IRF640 took was 26 volts and about 3.80 amps (at 30 volt and 4 amps it blew up). I had a 2SK1082 MOSFET laying arround but that doesnt work very well. I got a very little arc from that one. <br> <br>Please help me, I really need a MOSFET that can handle much more current/voltage and still give a nice big fat arc from the flyback. <br> <br>Greetings, <br>Jochem
<p>irf3205 it has 110 amps of current handling and 55 volts</p>
<p>there made for car batteries</p>
It's not really about the MOSFET handling current but rather the switching. Get some IRF540's on Ebay for about a dollar a piece and they're 100V, 30A.
Thnx for the reply,<br> I got 2 irfb20n50k's now. 500V 20A and I guess they can handle 280 watt at 25 degrees celcius. Atleast that is what I read in the datasheet. :) This MOSFET works great at 35V and 3.4A but I don't want to blow it up, haha. Got a 50V 16A (800VA) toroidal transformer attached to it with a variac and a 100V 22000uF capacitor.<br> This MOSFET don't get that hot with a CPU cooler attached to it and I got a pretty long and loud arc. But I guess the MOSFET can handle even more! :)<br> Here is a movie of my power supply and plasma speaker (only on 25V) :p<br> <div> <iframe frameborder="0" height="360" src="http://www.youtube.com/embed/XtfuMuHwWTk?rel=0" width="640"></iframe></div>
Sweet setup and spark! =)<br>When ever I bother myself to make another of these I think I'm gonna add a 148watt Peltier cooler. Might help those poor MOSFETS from dying? =)
good idea about using a cooler but one side of them gets really hot so your just moving the problem. im probably wrong. will the cool side being heated by the MOSFET cancel out the other side from overheating.
<div> Hey Crimson-Deity,<br> Here is just another video of my plasma speaker at 34 volt this time.<br> The arc is now longer and louder! :)<br> I will probably crank the voltage up some more in the near future, but I really hope I don't pop the MOSFET. :P<iframe frameborder="0" height="315" src="http://www.youtube.com/embed/YvvjjsOXlFk" width="560"></iframe></div>
Thnx, I still need to build the variac, bridge rectifier and capacitor in a box :) <br>And maybe I will build a volt and amp meter in it aswell. Looks alot better then a separate volt and amp meter if u ask me! :) <br>I bought this stuff a week ago so that's why it lays all over the floor. :p <br> <br>About dying of MOSFETS, I guess if u stay in the voltage, amps and watt range of what they can handle, u will be fine and keep them cool as possible. :)
<p>Thats helpful<br><br></p>
Alright. So i built this with blind luck (Many of the projects i try to replicate fail in some way shape or form...) And well, i was surprised it actually worked! The shock was electrifying!! (No pun intended) But alas, i do have an issue. <br> When i powered it on, it worked at an extremely high frequency, but even worse, it blew out my power supply! Now, this was an older power supply i scavanged from a satellite dish box or something (It had +5 +12 +22 and +30 which was much better than my ATX, considering it only goes up to +12 volts...) This being the first time trying it out, i thought maybe it was a bad power supply that was already bad, i just finished it off. I was wrong. I pulled out my 12 volt SLA battery, to use that instead. Not sure if it was the power supply's fault last time, i decided to only turn it on for a few seconds. The cable leading to the board got really hot, the battery got warm (Uh oh...) and the mosftet got hot to the touch; Only in a matter of seconds! Thankfully, the battery is still ok at the time of writing, but what would be the cause of such an issue? I am thinking it may be shorting somewhere, but looking with my multimeter i dont seem to find any errors. Only the mosfet and the power cables get extremely warm as far as i know. Any ideas? Great 'able BTW, was very easy to follow and understand.
UPDATE: Alright, so i swapped out all the wires with 14 gauge wire, which by the way is complete overkill, and tried using an ATX power supply. The ATX didn't even try powering it, being way too high of a current for it to do anything... <br>Any idea why this is happening?!
Is it possible to somehow use plasma globe (ball) as plasma speaker (ofc, when you take out the globe)? I have problem with flyback trasformer, I can't get it working somehow.. But, I have broken plasma ball so I have driver for ball which I don't need.. <br>Thanx in advice.
And the flyback transformer I can see it has a lot of leg so which one can I solder the coils in? And one more that can I replace the coils with the spark plug in the car?
I read it and I wondering that what can I do to protect my phone which will have a chance be strike from tesla coils? help me please!
<br>Nice...!! <br>
good one
good one
nice one
great one
very nice
nice one

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