Audio Modulated Solid State Tesla Coil

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Introduction: Audio Modulated Solid State Tesla Coil

About: My name is Daniel Kramnik - I like building Tesla coils, quadrotors, and robots!

Here is a video of my new SSTC, this test is only at 24 volts, and its already over an inch long, hopefully, it will be much more impressive at full power.

Here is a video of the coil running in audio modulation mode at 90 volts (this was an earlier test, so the arcs became longer later on)



Finally, we have a video of the coil throwing 7" to 8" long sparks at 90 VAC input.



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    37 Comments

    hello i want to make a tesla bobini but what i will do with it is the result of researches i can not reach the result i can not reach more than 22MV but i have not found much about it i am very happy

    How did you manage to get the spark so long at only 24 volts? mine is running at about 50 volts but the sparks are only about a quarter of an inch. :-(

    Please help me out !

    Hi, this Tesla coil you have built is amazing. I want to build an audio modulated solid state tesla coil of my own but have no idea how it works and where to start. I have already built a spark gap mini tesla coil using a bug zapper. If possible can u tell me how can i start, some links or just the basics i must understand before taking up something like this. Thanks!

    Hi, I don't understand one thing.. why does my secondary decrease to very low voltage when I set the pulse width from say 58% to 80% at the same set frequency, shouldn't I get a higher voltage???

    1 reply

    Im making this tesla coil and i was wondering if i could run it off 240v

    1 reply

    Yes, although you won't want to use a voltage doubler, and you'll need to use higher voltage rated FETs/IGBTs. Are you going for an SSTC or a DRSSTC?

    Wow! your coil looks really good, I am at the moment building a PLL SSTC after I seem to fail at making a tesla coils work from a flyback driven by a 555 timer. All i need now is a wide diameter pipe and MOSFET's, lol

    Also I am not too sure about the GDT, how many turns of wires they should be and what wire thickness too, will16swg work?

    8 replies

    Unfortunately, when I tried raising the voltage to 120VAC, all my MOSFETs started popping, I need to get some better ones.... Did you try building a coil with your ZVS driver? I've seen quite a few impressive ones on youtube.

    To answer your question about the GDT, I used 16 turns of 22 AWG wire (22 or 23 SWG) on a 1.5" diameter ferrite core. The GDT is one of those components that you will need to experiment with. I do not have an oscilloscope ( D= ), so I have not tested the output waveform, I just tried it and it happened to work. If you get a nice square wave signal on the secondary side, then you are fine. Use larger components rather than smaller ones, most gate drivers can handle quite a bit of current, and it's better to have a beefier GDT than to have one that won't provide enough current to turn the MOSFETs all the way on. Good luck!

    -Xellers

    MOSFET's starts going off at 120VAC? That is a little bit discouraging because the schematic I got (I can't show it to you because the site I was relying on is down) requires an 240VAC input for the SSTC. I really need to get a varic...

    I do happen to have a simple oscilloscope so Ill experiment with different GDT designs, thanks for your tip, it helped alot! :)

    And yes, I am thinking about trying my 'failed' tesla coils with my recently built ZVS driver. I also put an 1.5nF capacitor across the HV output just for the hell of it, and damn! The sparks are absolutely ear splitting without ear protectors, this is with 36V input. I really think it should work this time.

    What MOSFETs are you using? My IRFP260s were good for 80VAC, but my IRFP460s (high voltage rating, lower current rating) were useless even at that voltage. All of the schematics I've seen use a variac to bring the voltage up slowly, so it's definitely worth a shot, but I'm not sure why, since the dV/dt is still the same when the device turns on and that's my guess as to what's killing it. It could also be my GDT, my signal might not be a square wave or it might not be strong enough, either one could prevent the gates from saturating properly.

    Just out of curiosity, are you using one of the CD4046 feedback/VCO designs for your SSTC? Unfortunately, I never managed to get my PLL version working, and I'd like to see what you are able to come up with.

    Because good MOSFET's are a bit expensive, I can't afford to blow them up, so im using cheap IGBT's, it is IFG4PC30F, rated at 600V and 17A. I do have a varic, however, it is rated at 1.5A which won't do me very much good, lol :(. I'll keep looking for one at car boot sales and ebay.

    And yes... I am working on a CD4046 design, I found it here: http://uzzors2k.4hv.org/index.php?page=pllsstc1
    That would be a bit of a gamble for me if it does not work for ya..

    I'm planning on buying a variac and some new MOSFETs and IGBTs for experimentation - I'll try to post something new soon. As a sidenote, if you're afraid of killing transistors but want to experiment, I'd suggest something like Steve Ward's Class E SSTC. I assembled a small, single transistor Class E in about an afternoon and it worked great (until I tried to run it in CW - hint: don't do that =P ). However, be warned that if you don't add some sort of GDT, his schematic has the tendency to kill gate drive chips...

    You tried using a GDT on steve's class e? How did that work out? I have much too many UCC's that have been given an unfairly short life. :'( What core material did you use to prevent saturation at that high frequency?

    Actually, I managed to get it working pretty decently, the maximum spark length was about an inch in CW with 45V or 90V input (can't remember which it was). The original reason I switched to a GDT-based design was that my UCCs kept dying without one!

     Nice work, my first tesla coil I made was from a cardboard tube that kitchen roll is wrapped on. I took the wire from an old motor and used some wire you use on breadboards for the primary.
    For the power supply I used a flyback transformer driven by a 555 timer and had a spark gap and wine bottle capacitor.
    It worked but not very impressive, only about 1~2mm discharge into the air but it could light up CRT bulbs from a few inches away.

    Anyway i'm looking into solid state ones now and am planning on a proper build. Could you give me some idea of how many windings you have on each coil and what frequency you are driving the coil at and how you are driving it?

    Thanks, and i'm looking forward to the next SSTC you build =)