This is a simple solid state Tesla coil with one MOSFET

Step 1: What You Will Need

IRF 540 MOSFET (other similar mosfets will work IRF 510, 630)


50 Ω resistor

1 kΩ pot

1 μF capacitor

Cardboard, glass or bakelite tube

Step 2: Operation

The secondary coil gest warm or hot, use cardboard, bakelite or glass tube. The secondary is made of magnet wire 200 - 400 turns, 0.1 - 0.2mm thickness. The coil dimensions are not critical (30 - 40 mm diameter)

The primary is only 1 turn, 4-5mm bigger in diameter than secondary, 1mm magnet wire, placed at the bottom of the secondary.

Turn the 1k pot when the spark discharge appears on the top of the secondary. At best adjustment the spark is longest and the mosfet gets warm slowly. If it don't oscillate, change the connections of the primary!

Resonant frequency depends on secondary coil dimensions and number of turns. It's between 2 and 10 MHz.

If you operate this tesla coil at higher performance (40-50W) the mosfet gets hot, it requires large heatsink.

Placing a top capacitance to the secondary, the spark gets longer, and the mosfet will be cooler.

The spark produces ozone!

Step 3: Video

<p>I always wanted to make a Tesla coil, but the ones I found looked pretty much too big. This seems to be a nice one. What's the wattage of the 50 Ohm resistor?</p>
<p>How to protect the gate from 40v 0.5A because irf540 is only 20 gate voltage</p>
<p>Adjust the pot between gate and source to minimum (between gate and 50 ohm to maximum) and increase it slowly when a small plasma flame appears. That's the correct adjustment. With a large heatsink, during adjustment, I did not burn the mosfet.</p>
<p>The resistor is 2W, my device is running at 40V, 0.5A = 20W. The resistor doesn't get hot, I don't know what about higher performance.</p>
<p>Can I use a 51 ohm resistor instead of a 50 ohm resistor?</p>
<p>For sure. General resistors have an accuracy of 10%. 50% +- 10% gives a range of 45 Ohm to 55 Ohm. So even with a 5% accuracy you would be on the safe side.</p>
<p>Thanks for the fast reply!</p><p>I am planning to build this little tesla coil.</p><p>I have a few more questions:</p><p>How did you make the 40v power supply?</p><p>How many secondary windings did you use?</p><p>And in which direction do I need to wind the secondary coil?</p>
<p>Buy a step up boost regulator, or you can just make one for fun. If you dont know what a boost converter is, its basically takes low voltages and converts to a higher voltages. search them up. </p>
<p>How many secondary windings did you use and in which direction do I need to wind it?</p>
<p>Hi! Sorry, I know I reply late, but I was busy recently. 51 ohm will work well. Doesn't matter what is the direction of the secondary, if there is no oscillation, change the polarity of the primary. It's easier. First, try with 200-300 turns on a cardboard tube. Power supplies between 20 and 40V will work. My power supply is a small, 20W transformer from a satellite receiver, a rectifier bridge, and a filter capacitor. Good luck!</p>
<p>I only have a cardboard tube with a diameter of 5.5cm, will it work?</p>
<p>Yes, diameter is not critical, but you can use glass, bakelite tube etc. any other material that not melt because secondary coil gets very warm, almost hot during operation.</p>
<p>I already found a smaller cardboard tube. But is there any way I can get this tesla coil audio modulated? I've seen a video of someone who added audio to the mosfet via a transformer so the high volatge is seperated from the audio input, but hoe can this be done? There aren't any instructions on the internet.</p>
<p>Audio tesla coils are more complicated circuits. You can try it by modulating primary current or run this sstc from a power amplifier, but these are not the best solutions. Audio fidelity will not be very good.</p>
<p>I know, but I've read something about adding audio to the gate of the mosfet.</p>
<p>This is a slayer exciter circuit. I think when audio is attacded to the gate, it confuses the operation of the circuit.</p>
<p>To test operation, place a small neon glow lamp or a compact fluorescent lamp close to the secondary, in case of oscillation, it will glow. Plasma corona not always appear at the top of the needle.</p>
<p>Take simple paper, roll and glue it to the diameter, the author suggests. </p>
<p>Im not the author of this instructable, but he siad 200-400 turns, you can wind it in any direction you want, you can also wind the primary any way you want, but if it doesnt work than switch the connections of the primary. </p>
<p>I'm not the author, but according to what he said it&Auml;s 40V at 0.5 A (20W). Either you take a simple transformer with rectifier and large electrolytic capacitors or you have a lab power supply. Regarding the winding direction: I don't know. But the first has only one winding. So if t won't operate the one way just turn that around and you should be done.</p>
<p>I don't need to go up high. So your circuit has the right size for me. It seemed that all people doing Tesla coils want to do it at the size Tesla tried it (this Tesla tower). My lab power supply can deliver 30V so that should be fine according to your numbers. I'll give it a try (when there's time...).</p>
<p>Good luck!</p>
<p>The resistor is 2W, my device is running at 40V, 0.5A = 20W. The resistor doesn't get hot, I don't know what about higher performance.</p>
<p>irf540 and irfp260 that I used have max gate voltage 20V , when I apply 24V mosfet burns !! how to protect mosfet , can I conect irfp260 in series or use other mosfet !! can zener beetwen G and S protect it from overvoltage!!!!!!</p>
<p>First, the pot between gate and source must be set to minimum resistance, then slowly increase it until small plasma flame appears on terminal. wneh the plasma is the longest, it is the proper adjustment. Don't run the device long time with inproper adjustment, and use a large heatsink. I have no problem with irf540</p>
<p>Hey Man </p><p>Amazing circuit and output you have but i have a 18v 3a supply will this work?</p>
<p>Try it, if it will not work, build a simple voltage doubler.</p>
<p>works but I use irfp260 and I burned 2 of them</p>
Nice dude will this work at 12 volts ,i got 4 mosfets rated at 150v 45 A at continuous use,but minimum gate voltage is 10v to turn it on will it work?
<p>so cool, but you should use mosfet z44, the lighting is bigger</p>
<p>Yes, but I have only this type of mosfet, and unfortunately I have no stronger power supply.</p>
<p>but if i have a coil look like coil transformer and it's stacked coils, so can I do tesla by it?</p>
<p>I think you have to rewind them this (or similar) way.</p>
<p>can i use 2 turn primary and 900 turn secondary?</p><p>48v ok?</p><p>interrupter ok?</p>
<p>I don't know, try it. If it will not oscillate, change the primary (1 turn). If it still not oscillating, decrease the secondary to 400 turns. 48V will ok, but be careful not to draw high current or use a big heatsink! It did not try it with interrupter.</p>
<p>If this jamms radio active frequencies it is Illegal in the United States if the jamming occurs past your property line. </p><p>https://www.fcc.gov/general/jammer-enforcement</p>
<p>Tesla coils are radio wave sources too. It has no antenna, the performance is low, so the jamming range is very short. It does not produce broadband noise, it operates on a certain frequency between 10 and 2 Mhz. I don't know exactly, it depends on secondary coil.</p>

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