Music, Magic and Mayhem with Tesla Coil

Tesla coil is not all about big and loud sparks:

DISCLAIMER: Also watch the following video. The circuit I made works and can output music, but it is very hard to tune and operate and can blow up easily too! Well I designed it so what do you expect?! It was the fast and dirty solution to make arcs sing. So if you like to take the challenge and make it, be very careful and patient. I should design a better circuit when I have a chance.

Tesla coils can be very quiet, or musical! Isn’t that strange? I always thought an arc makes a big sound. But the noisy ones only make big sound because they have low frequency components in them.

If you don’t care about the circuit and want some answers to what you saw in the video, skip all the way down to “Explaining Video Scenes”.

Tesla Coil and Solid State Driver

Tesla Coil and Solid State Driver

But before I elaborate on the circuit:


  • Death is close by, try to prevent it!
  • The radiation from this device can easily interfere with electronic devices, like pace makers. be very careful. All my touch screens were messed up being within a meter of the coil.
  • This circuit can burn your skin badly (see picture at the end)

If you go back and read my Slayer Exciter article, there I explained that it is made of two windings, a primary with very few turns (around 10), and a secondary with many turns (around 1000 and above). But what you should know is that every inductor has a stray capacitive component and every capacitor has a stray inductive component.

For the secondary we intentionally increase the capacitance by adding the top load (the toroid on the top) which crease capacitance to the surrounding material.

This capacitance and secondary inductance create a sharp resonance frequency, which is very sharp! It basically means that only at that resonance frequency you will have a virtually infinite impedance, where all the energy can be radiated in the surrounding world.

That frequency is :Where f is frequency, L is the inductance and C is the capacitance.

Now for the primary to be able to transfer the maximum power to the secondary and radiate it to the air, primary must also oscillate at the same exact frequency. In old time Tesla coils or spark gap type in general, a capacitance is also added on the primary side that is tuned to resonate with the primary inductance at the same exact frequency. You see the spark gap type driver below. It is still a very practical method when you need to make extremely large voltages.

This is one of the ways Tesla did it

This is one of the ways Tesla did it

In this type, the AC power input which is typically at 50Hz or 60Hz is amplified by a transformer to thousands of volts, which charges the high voltage (HV) capacitive. In every cycle of the AC, the capacitor voltage reaches very high voltage twice (negative and positive peaks),which is enough to break through the spark gap. The ionized air of the spark gap shorts air, and the HV capacitor to the primary of the Tesla coil. Now the capacitor is across the primary which will oscillate at the secondary resonance frequency, transferring all that energy and creates a super huge voltage on the output of secondary.

The super loud noise of this type is simply because you have a lightening every 100Hz or 120Hz.

Having a solid state driver, like a slayer exciter or the one I explain below, you can run your circuit continuously at the resonance frequency using the fast circuitry that can oscillate at coil’s resonance frequency. Below is the schematic of the circuit I designed.

This circuit takes two input supplies, one at 12V at J1 connector, for which I used a 12V wall adapter, and VSUP, which I used my lab power supply at 32V for this video. You can also make the 12V from VSUP using an on board inverter. Originally I wanted to use my Full Bridge Rectifier and run VSUP at 170VDC rectifying the 120VAC. But that voltage was too big for my circuit and for the reasons I also explained in my Tesla Coil Half Way Report my MOSFETs (Q1 to Q4) blew up. I have plans to get around the issue but for now I discovered much beauty even at lower powers!

Solid State Tesla Coil Driver

Solid State Tesla Coil Driver

Here’s the Bill of Material for my circuit:

  • R1 and R4: 1k Ohm
  • R2 and R3: 10k Ohm
  • R5: 100 Ohm
  • R6: 2.7 Ohm
  • POT1: 1-1623849-0 (multi-turn trim potentiometer)
  • POT2: any single turn 100k potentiometer
  • C1 and C4: 100uF, >16V
  • C2 and C5: 10uF, >16V
  • C3, C6 and C8: 100nF, >16V
  • C7: 100pF, >10V
  • L1: 10uH, >2A
  • U1: MC78L05BP-AP or similar 7805 5V regulator
  • U2 and U3: MCP6562-E/SN (dual comparator in one package)
  • U4: MIC4452YN (MOSFET driver IC)
  • Q1 to Q4: SCT2450KEC (Power MOSFET, 10A, 1200V)

This circuit is pretty simple. The 5V supply is created by U1 that feeds the low power comparator and OpAmp circuits.

The 12V supply is separately filtered through L1 and capacitor to supply U4, the MOSFET gate driver. The reason is that this driver draws large current spikes to quickly drive the MOSFET gate capacitors and the noise on the supply can easily effect the oscillator circuit, while we need an accurate frequency. It is also important to pay attention to the ground routing. Make sure the ground for the oscillator circuit is not supplied through power circuits (MOSFETs, gate driver).

U2 circuit is an Schmitt trigger oscillator circuit. It’s frequency can be tuned somewhere between 500kHz to 1.5MHz using the POT1 potentiometer. My Tesla coil resonance frequency is around 1MHz. The output of the oscillator circuit where I’ve taken it from the capacitor C7 is a saw tooth waveform. I did it intentionally because I wanted to create a variable duty cycle PWM signal. So I compare the saw tooth signal with a DC voltage created by POT2. Depending on the level of the DC voltage, the duty cycle of the PWM can be tuned. Below is how the PWM changes by the DC level compared to saw tooth signal (click to make it move). This is similar circuit I used in Making an Electric Tooth Brush. Just that my PWM signal is inverted to what you see below. I didn’t want to remake this gif just for an inverted signal!

PWM Signal generated by comparing a sawtooth wave with a DC level

PWM Signal generated by comparing a sawtooth wave with a DC level (click to see animation)

Now the PWM goes through U4 gate driver which will switch MOSFET transistors Q1 to Q4 on/off. I used 4 transistors so that they can share power between them and don’t get too hot. I also mounted them on a heat sink because they get quite hot.

Now when MOSFETs turn on, the primary is charged with current and when they turn off, the energy converts into a large voltage spike on primary that generates large voltages on secondary. The arcs are very quiet, like I mentioned and you seen in the video.

Important Functional Notes:

  • Very important! Don’t use metal a screw driver to tune your circuit. It may burn your finger and it will mess up your frequency. Use a plastic or wooden, rather long screw driver. I carved my screw driver from a long stick.
  • The arcs will not jump out directly from the toroid as it still doesn’t have mega volt levels. You need to simply place a rod or some metal with a sharp tip so arc can jump out of it.
  • You need to accurately tune the frequency for the arcs to come out. But every coil has its own resonance frequency. To find what it is, make the simple Slayer Exciter circuit. When your coil works well with the exciter, probe the base of the transistor with a scope and measure the frequency and voila! you know the resonance frequency.
  • The resonance frequency can greatly change based on the environment around the coil. For example if you bring your hand close, or place different objects around it, the stray capacitance will change, changing the resonance frequency. This circuit, unlike the Slayer Exciter, doesn’t have a feedback to automatically tune the change. So if you change something, re-tune the frequency to get biggest arc. For example in my video, for every scene I had to re-tune it based on what I was bringing close to the toroid. It will be close to the original frequency though, so turning POT1 back and forth a bit, you will find the peak.
  • For maximum power, tune the PWM duty cycle to 50% to 60%. Above or below this duty cycle will not yield any more power.
  • Before applying VSUP, turn the 12V supply on, make sure all your circuit works, tune the frequency to what the resonance is supposed to b. Then turn VSUP on at a lower level and tune your arcs a bit, then ramp it up to maximum (32V in my case). Then tune the frequency further (very slowly) to get the arcs going best.
  • Don’t run the circuit for too long as the MOSFETs will get quite hot and can burn, killing R6 and U4 with them. A good heat sink is important.
  • On that note, buy many spare parts!
  • VSUP can be further increased. I have tried 45V also and my arcs get bigger. I have also tried 170VDC from my bridge rectifier with large arcs. But it is on the edge of destruction there. If you have an auto transformer, you can tune down the AC supply to your bridge to protect the FETs but yet get bigger arcs. The reason they break at higher voltages is that when the MOSFETs turn off, the primary voltage jumps high. If it goes above the 1200V rating of the FETs, they enter avalanche mode and get very hot and eventually break. Great heat sinking is key.
  • The arcs may get noisier at higher power because they will start loading the supplies and VSUP wouldn’t be a nice and clean DC, creating noise at the output.
  • POT2: something you should note that U4 has a strange behavior. When the input PWM duty cycle goes below some value around 10%, the output of U4 actually generates bigger PWM and can jump close to 100%. That is not good. So make sure you know what that level is on your potentiometer and not go below it. You can add a 15V series resistor between your POT and ground. That’s what I used and it ensures the DC voltage doesn’t go too low.
  • One more important thing, make sure physical bottom side of both windings are connected to DC levels (primary bottom to VSUP, secondary bottom to ground or VSUP). If you do it another way, you may get weaker sparks.
  • I connected the primary to my circuit using alligator clips as shown in picture below. The red wire is VSUP and the black wire is coming from the MOSFETs. Moving the black wire can change the number of primary turns. You can increase the size of your arc by tuning the black wire location.
Primary Connections of the Tesla Coil

Primary Connections of the Tesla Coil

You might ask why I didn’t use a feedback like the slayer exciter circuit to auto tune the resonance frequency. It was because I wanted to make high quality audio, which was very simply done with this circuit. Having audio is also possible with the auto-tuned circuit, but you will get saturated sounds with that one, not a nice music like this one with such simple circuit, unless you want to get fancy with your driving circuit. Here’s a snapshot of the circuit:

Tesla Coil Solid State Driver Circuit

Tesla Coil Solid State Driver Circuit

Making the Most Dangerous Speaker

Now I moved POT2 and placed an OpAmp Circuit shown in picture below. J2 is an audio jack, or in my case I just cut a broken headphone cord and soldered it to my circuit. I could plug the jack to my cellphone or laptop.

U5 circuit basically amplifies the audio, with a gain tunable with POT3. POT2 still has the same effect as before. It tunes the average duty cycle while the audio input modulated the duty cycle with audio signals around the average PWM. The change in PWM creates a change in output power of arcs and so creates sound.

Tesla Coil Solid State Driver with Audio

Tesla Coil Solid State Driver with Audio

Here’s the Bill of Material for new components:

  • U5: Any standard OpAmp with an output that can reach zero would work. I used LM358.
  • POT3: Same at POT1, multi-turn potentiometer
  • R7: 1k Ohm
  • R8: 10k Ohm
  • C9: 10uF >10V

Now this is some manly speaker! Why would anyone create sound using a diaphragm when you can use arcs instead?!

Explaining Video Scenes:

  • Yes, the arcs are very quite like I explained. This is especially great because it means you can play music with it without too much background noise.
  • When you bring a florescent light close, it turns on. The super high voltage excites the florescent material in the lamp like I explained in Slayer Exciter video.
  • Using the incandescent light is pretty cool. You can see the plasma made in the lamp and the flow of electrons like dancing flames. The special form of plasma in the bulb is due to the gas in it. As you see in the video as soon as the glass melts and breaks under the extreme heat of the arcs, regular air gets inside and the arcs look the same as ones in the air.
  • Of course the glass is non conductive. What you should remember is that there is no continuous one way flow of electrons. The arcs you see are electrons jumping back and forth at 1MHz frequency. This means that at that high of a voltage we just have a capacitor between the toroid and the light bulb contacts attached to my hand. The capacitor insulation is air and glass. In every 1MHz cycle, the electrons jump to the glass pushing the electrons inside the bulb away, and then the toroid sucks them back in leaving positive charge at the glass, which will pull the electrons into the bulb, and that’s the flow of electrons creating the plasma. There are no electrons passing the glass, of course until it breaks.
  • My spinning wheel, it was beautiful! There’s a jet of electrons shooting from the ends, of course, but it is not the weight of electrons jumping out that turn the wheel, no siree! The mass of electrons is almost zero. And they are not jumping out anyways, they are jumping out and in at 1MHz frequency. So what is turning the wheel? It is the expansion of air due to the heat of arcs that pushes the rod away. The arcs are pretty hot. In fact when I bring my hand close to them, I can feel the heat rising from them.
  • The arcs don’t zap like regular electricity. Yes, that surprises me too. It has something to do with the no noise nature of these arcs too. If arcs make noise, they are much more dangerous! Why? Two reasons: first, at such high frequencies like 1MHz, your nerves or muscles don’t react to the electricity, so you won’t shake or jump. But it is not really the reason why they are less dangerous. Second: they are less dangerous because of something called “Skin Effect”, which is not about human skin, but rather conductor surface (skin). Look it up. Basically as the frequency rises, electromagnetic fields are created in a conductor that push the flow of current to the surface of the conductor in a thinner skin, and less is passed through the central area of the conductor. That’s called skin effect. For 1MHz, the most of current can only penetrate around 60 micro-meter deep into a conductor. For a human, it means it will no go deep enough to effect vital organs like brain or heart and remains on the surface of body. The arcs that make noise have low frequency components in them in audible range. These frequencies can penetrate deeper in the body, shake muscles and be lethal.
  • The arcs, jumping directly to the finger, burn the skin black. See my picture below for burns from all that testing. The reason is that the arcs enter a small spot and all that energy through a single spot makes a localized hot spot burning the skin. Another reason is that the skin is made of dead non-conductive cells. So when the arcs pass through such high resistance layer, they create a lot of heat and burn it. As soon as electricity reaches conductive tissues, it disperses around to larger surfaces that generate much less heat.
  • But why doesn’t it hurt when I hold a metal in my hand and touch the arcs with it? Because the metal provides a greater surface to my hand and rather than a spot, there is a bigger area for electrons to move into my hand. So the heat dissipates on a bigger surface rather than a spot and doesn’t burn anymore. Also when I hold the metal, I put a pressure which makes the non-conductive skin thinner and less resistive. But if I touch the same metal at a single point with not much pressure, it burns my skin.
  • Why do the arcs jump to a floating metal object like my screw driver? Simple! It is not like they jump to the screw driver to jump somewhere else. Screw driver is like another plate of a capacitor, which has a tiny bucket of charges in it. So what the coil does is that it sucks out and pushes back in that tiny amount of charge away/to the screw driver.
  • Even when the arcs are not jumping to the screw driver it zaps my finger. Screw driver, just being close enough to the coil, peaks up electric fields, like another plate of a capacitor. Those fields are so strong that they can suck/push charges from my finger.
  • I love the audio I created. I showed you two tuning of the circuit, one that sounded nice and smooth, and the other which sounded saturated and jumpy. For the smooth one, you have to raise the PWM to around 50% and reduce the audio gain to prevent any saturation of PWM signal. For the saturated one, you have to lower the PWM so much that arcs don’t jump. But then raise the gain so much that the PWM level can jump to 50% or 60% or more. That way the low level audio doesn’t pop out, but usually the bass which is a higher pop pushes a high PWM and causes the arcs to jump. And the arcs created this way can jump further too.
  • The popping arcs from my saturated audio jump much further and sharper than the fuzzy arcs of the smooth flow. I believe the reason is that when the arcs are continuous and consistent in level, the air all around the pin is ionized and the energy flows in every direction continuously like you see. This makes the arcs shorter too as they are not focused anymore. But when they pop out in single bursts, the air has time to create only one ionized channel and all energy flows through there. So it jumps further.

Now if you wonder how my skin looks like after so much burning, here it is. All those burns were surface deep and the black burns could be washed away, although they left small blisters here and there, because, well, they were hot! Don’t burn yourselves! and DO YOU REALLY KNOW HOW I GOT THOSE BURNS?!

You may thing I got them from touching the coil. Half of them maybe, but the other half was from touching metals around me, or turning the damn camera on/off! Every time I tried to touch something while the coil was running, it would burn me. Just sitting close to the coil, my body would peak up enough energy to zap any metal I touched, same as touching the screw driver in the video. Almost ten times I forgot to turn the coil off, while tried to turn the camera off and saw smoke coming from my hand and camera. Fortunately the camera was not damaged.

My finger burns from Tesla Coil

My finger burns from Tesla Coil

And more shots of my beautiful coil:

Tesla Coil with Solid State Driver

Tesla Coil with Solid State Driver

Tesla Coil with Solid State Driver

Tesla Coil with Solid State Driver

469 thoughts on “Music, Magic and Mayhem with Tesla Coil

  1. Assalam O Alaikum Mehdi. I’ve been inspired by your Tesla coil circuit. I’ve chosen this as my university project. The problem is none of the ICs and MOSFETs are available in Pakistan. Can you suggest me multiple alternative components.

    Thanks in advance for your prompt reply.

  2. Hi, i finish the circuit bit when i conect the 5v, the voltage drops to 0.8v, it may be because one of the components Is broken or malfuctionating. If someone know anything about this i would apreciate your help. Thxz

  3. Mehdi S.
    I’m a little late to this party, but fully enjoyed reading your tutorial. This is GREAT work, even with heavy eye brows 🙂
    I’ve seen other coilers describe using a micro-processor as the oscillator source and then a 3rd winding (tertiary) to pick up peaks to re-tune frequency real-time. Given enough shielding to said micro, it’s internal A/D could be used as a slow (~500 mSec) loop to peak the operating frequency; maybe it only runs for 10 – 15 sec and it done.
    What am I missing? ???
    Thanks for all your incredible videos!
    I’m a retired EE from Univ of IL and worked RF/ microwave for 35 years.

  4. What dip-8 packages do you suggest for MCP6562-E/SN? I hate soldering smd’s! Is there an alternative for the smd package: MCP6562-E/SN. Just any component that is on Digi-Key, duel comparator, and it is a through hole soldering. I have trouble finding it. Do you have any ideas?

  5. You should be using IGBTs. It’s possible the reason your MOSFETs keep blowing up is that you are running too much current through them… or maybe the heat created by using high voltage transistors (high rdson) is just too much. Either way you should try to lower the voltage of the ‘Fets, and up the current. Also you should add a resonant capacitor to the output – you’d probably get much hotter (and longer) arcs.

  6. Hi there, is it possible to replace the audio opamp circuit with a proper class a/b or class d audio amplifier? And if so, does yield better sound quality on the output?

    • No because the Audio Signal has to be PWM modulated and the audio opamp circuit converts an “analog” Signal to an PWM modulated. You could use an class d amplifier and remove the Inductor(s) but it would’t make sense at any point.

  7. Hi mehdi!
    I would like to ask a few question
    Why is my circuit turns to 90% duty cycle while i was tuning about 50-60% cycle it change it’s self to 90% of the duty cycle
    what should i check it? Is it the comparator or the driver should i checked the most ? I checked the mosfet all of is fine ……
    And i still can’t figured it out i checked all
    Please help me
    Thank you

  8. Hi Mehdi!
    How did you connect the multi turn potentiometer did you connected
    Pin1 to pin3 or is it pin 1 to pin2

    Thank you

  9. Hey I really like the idea of your circuit (low sound and danger but really good audio clarity). Is there any part or circuit adjustments I could make to your circuit to make it more stable? As in not having to worry about parts overheating or the mosfets exploding as you mentioned. I’m rather new to electronics in general and I’m not sure I would be anywhere close to as good at problem solving and tuning as you were so I feel like I would need to be comfortable with my initial design and that it won’t break after a short time. Whether you can help me or not, thanks for everything you have already provided.

  10. I would like to ask if the VSUP is connected to the primary coil, and then to the ground or the negative electrode. Also, please hand in hand welding circuit board to the back of the film, sent to my mailbox please!!!

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  12. Are you using a resistor to limit the primary winding current? Seems like the FET’s you are using (Rds on = 0.45 Ohms) would draw > 30A continuously while at 50% duty cycle with your 32V VSUP supply, exceeding their 10A continuous limit…

    • No, their current is limited by the inductance of the primary at 1MHz resonance frequency. For example if the inductance is 10uF, the impedance would be around 60 ohms and that limits the current a lot, that is until the power is being drawn from secondary. In that case the inductance of the primary drops and allows more power to go through, hence more current.

  13. Hi,

    I think you need a spark gap parallel to the primary coil or a Diode parallel to the Mosfets. The current now flows over the Mosfets (Drain to Source) when they’re switched off. That kills them.

  14. I survived it! And I did blow Q1 to Q4 with too much voltage. Also had problems with circuit not generating high enough frequencies. Originally the highest frequency I could tune it to was 500 kHz. I tuned some of the resistances in the frequency generator part of the circuit and got the desired frequency range.

    • Hi,I am your fan from Chian.I also want to make a Tesla Coil.But the IC MCP6562 is very difflcult to buy in China.So I want to know what IC can eplace the MCP6562.Thank you.

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  16. You need a capacitor between primary coil and MOSFET drains to prevent DC. Use a large value film capacitor that can handle some current and make sure the filter it makes doesn’t block your resonance frequency.
    My 2 cents!😉

  17. Hey Mehdi,

    We have successfully been able to build the coil and see it work. Currently it can create arcs into the air that are length 1-2cm. However the problem is that we cannot get the coil to sing properly, as we adjust the gain(POT3) and duty cycle(POT2), we are only able to cause the coil to turn from completely silent into a quite hissing noise, could you suggest a reason for this?

    Thank you in advance!

    PS – Could it be because we are not using a top load? We made a top load similar to yours however it only made the arc length shorter even when we put a pin on the top load.

    • Hey Mehdi!!!!!!!!

      We have just been able to make it work!!!!
      It was such a heartfelt moment! After working on it for a month it finally works!!
      Thank you so much for this guide and your videos are always great! Please do keep it going!

    • If the overlaps are just side windings it is OK. It is not OK if you turn the winding back onto itself, because then you are putting high voltage and low voltage side by side that will arc through insulation of the wire

      • How did u decide your mosfet driver? I’m looking for a good one I can drive two high voltage mosfets with high frequencies in RF range, and I’m having a hard time with mosfet drivers and how to use them, any tips please, so I can beef up the sstc lol

      • Hi mehdi I tried to build your circuit, and it works perfectly
        The only problem is that when the signal (with no problems)enters the gate driver, it slows the frequency to few hundreds of kHz on the output and it doesn’t work, because resonance frequency 1MHz

  18. Hi mehdi, I have seen lots of vedios of tesla coil and when I finally saw your vedio I liked it very much, but I couldn’t find a high voltage source, so what do you suggest I do?

  19. Hi Mehdi. I ordered the correct parts for this, and I am currently about halfway through building it, except the dual comparator package (U2 and U3)has only one comparator in it. I thought they must have not put in the second one, but then I looked at the photos of your circuit, and I saw that you had only one of the comparators as well. I am stuck at this point because I am unsure of how to use only one comparator when it seems that it needs two.

    • Okay, I see what I did wrong. There are two comparators in the same package. I get it now. However, I am not sure of whether to connect the source pin of the MOSFETs to the common ground of the board or not.

  20. Hello mehdi I have a little doubt that the MOSFET MIC4452YN works and there is some kind of replacement for this. Greetings and thanks

  21. Hi can i use a pair of transistors to drive the mosfets instead of MIC4452YN? Because i can’t find the driver ic with high current in my country.

  22. Hi,
    is there any alternate way that I can measure the resonant frequency of the coil?
    I do not have an oscilloscope.
    or is there any other way that I can tune the coil without measuring the frequency?
    maybe through the output voltage?

    • Hi!
      Try to increase the capacitance of the secondary,by increasing the size of the top load(torus).If you do this,you will decrease the resonance frequency of the secondary.Then use a microcontroller to generate a variable frequency accordingly to the resonance frequency of the secondary(more or less 1MHz).Use the slayer exciter circuit,but replace the current limiting resistor at the transistor’s base to a 1k and connect it to the microcontroller’s output,instead of the input voltage.The secondary’s feedback wire can be left unconnected.
      Measure what frequency are you generating by the microcontroller on the serial monitor.If the circuit works,the generated frequency is the secondary’s resonance frequency.
      Important:Make sure that the microcontroller is out of the secondary’s magnetic field and don’t touch the microcontroller or it can be damaged by static electricity.

      • Update:My feedback was connected to the transistor’s base and it drived the transistor.The microcontroller was just a power supply.Sorry for the wrong answer.But you can measure the resonance frequency with the microcontroller…

  23. Hello,Mehdi!
    I experienced some days with the slayer exciter circuit.I connected two power BJT’s in parallel and some 12V wall adapters and transformers in series,and I got around 100V output wich made nice 4-5 cm arcs from the top load,by a needle.
    I want to build the same circuit with mosfets so i got two mosfet drivers IR2110 and IR2153,which I could buy.I used the IR2110,because it have an input pin which can drive the mosfets by an input signal.
    The 2nd circuit from the slayer exciter project(the mosfet driver circuit)doesn’t seems to work…

    My questions are about the U1 and U2.The U2 output is a PWM square wave with adjustable duty cycle from 0 to 100% and frequency from 500kHz to 1.5MHz,accordingly to the primary’s resonance frequency?
    Also can I use a LM393 or LM324?
    What happens when you connect the music?The music changes the duty cycle or the frequency?

    P.S:I love your videos and I watched all of them at least 5 times 🙂

    Thanks for the reply!

  24. Hey Mehdi, we have been attempting to replicate your circuit with little success. Although we have been able to overcome several issues, we have not been able to increase the frequency of the oscillation that comes out from U3. The maximum frequency that we were able to achieve was about 500kHz. Could you suggest a reason for this?

    • Hi Matthew,

      Will yo check you R1 to be 1K and C7 to be 100pF to make sure? If your C7 is 1nF instead, or your R1 is 10K instead, you frequency would not exceed 500k. Also maybe your POT1 doesn’t go all the way to zero.
      Another issue could be stray capacitors in your circuit that reduce your frequency? Are you using a bread board (solder less things)? They usually have high capacitance. Use a prototype board and solder your circuit in.

      • I Can’t even obtain a saw tooth wave form from u1, I checked the values and resistors and cap are 1k and 100pf but the only thing I can get from u1 is smooth dc voltage, and when I set pot to 0 a noise requency of about 300hz. That is the only part of the circuit that I’ve problems with, perhaps cap voltage is axactly 10v?connections with u1 are perfect, I could also get a smd adaptor…

      • Hey Mehdi,

        Thanks for your reply, we have been able to achieve higher frequencies since we realized an error in our usage of POT. However the results were not particularly optimistic as we have only been able to create stable oscillations of the output wave at ~3MHz, anything below that would cause unusable waves as seen on our oscillator.

        We have instead been able to reconstruct the coil as a spark gap tesla coil successfully, creating large arcs. However we are not satisfied by it and would like to give another shot using a prototype board (we tried to make the previous one using PCB). We just had to see the high quality audio for ourselves 😛

  25. Hi Mehdi,

    thanks for all your funny and very informative videos! I like them very much!
    Since I read this often and since I may lead to false conclusion and may risk one health or live:
    The high voltage of a well tuned tesla coil only creates a measurable skin effect in
    materials with low impedance like copper. The human body has a comparable high
    impedance and therefore the “skin” where the current is travelling is much much thicker…sometimes thick enough to touch ones heart.
    And nonetheless…the high voltage makes the current flow…even if it is far less
    than what creates an “electric shock”.
    The reason why one does not feel “shocked” when getting “tesla”ed is:
    The ions inside the human body does not travel far enough (due to the high frequencies) to create an electric field inside the body cells which is long enough
    to reach through the cell membrane. Therefore no nerve gets “fired” and no shock
    is felt.
    BUT: The current is still traveling to ones body and the result can be damaged tissues for example in joints – which may feel bad.

  26. Hey man, so I understand why you don’t get an eletrical shock. If I’m correct, it’s because of the “scin effect” which leads to high frequency voltage building the current at the surface of the conductor instead of inside the conductor. So the voltage doesn’t go through your inner body, it only gets conducted by your skin.

    However, why did your skin get burned when moving your fingery near the coil, and more importantly, why DIDN’T they get burned when you held the peace of metal in your hand and moved that near the coil? Does anyone have an idea on this?

  27. Why did you use four mosfets ?
    Can I use one mosfet?
    What is the value of frequency you used in your circuit?
    Which one is better to use high frequency or low frequency?
    What the function of the torus?

  28. Why did you use four mosfets ?
    Can I use one mosfet?
    What is the value of frequency you used in your circuit?
    Which one is better to use high frequency or low frequency?
    What the function of the torus?

  29. Hello mehdi I am honestly very fascinated by the coil, I must admit that I like it enough, I for my part am doing the coil with a teacher, I already have most of the components but I do not find the four MOSFET Stc2450kec and Ni the Mic4452, If you can help me with some kind of replacement that can replace them, with these components already mentioned, many gacias and I wait your answer. regards

    • Drive the coil with simple slayer exciter and measure the oscillation frequency on the base of transistor. That would be your secondary resonance.

  30. Hi!I’m a student from China.I’m very exciting to talking to you! I have some questions:A ground circuit diagram on your home, but the real figure on the wire without wire. Also, I see you have a lot of broken circuit on the map, I do not understand what is the meaning of. I have a wish, I would like to ask you to explain in detail the circuit with music. By the way, I would like to ask you to tell me your email address. Please!

    • Hi.
      I Don’t Understand the first part of your question.
      You must know the schematic symbol and make electronic circuits.
      In the Schematic U1 is a 5V Regulator Like L7805 , for U2, U3, U4 , You Should Read The Datasheet . If You Know the schematic symbols You’ll have no problem in making the circuit.
      You can make the Simple Tesla that available on this website.

    • Hi,
      I had the same problem when I first saw this diagram. then I realised that the ground in all of them is actually a common ground and everywhere it is that you see a ground symbol it is connected to the negative terminal of the dc source

  31. Why there is no primary capacitor in your final schematic?
    another question, Shouldn’t tesla coils operate on AC voltage, why do you use V_SUP(32V)?


    • Actually, you conect the vsup to the primary coil, then you have the mosphets which are oscilating at a very high frequency so you switch between an open and a close circuit, and make the ac power for the coil

  32. Hi, Mehdi! Currently I’m working on a ZVS and thought, that it’d be nice if it could sing like your Tesla Coil. While looking for a circuit that will convert audio signal to square wave and then turning the MOSFETs on I remembered your video about Tesla Coil audio modulation, hence my question. Is there a way to build a circuit that would switch the MOSFETs on and off depending on audio signal?

    ZVS circuit:


    • Well usually the more winding gets you more voltage. But if your tower is too long that t he primary fields hardly reach the top, then more winding will not make much difference. So it depends on yur primary and secondary dimensions too. There are calculators on the web you could use.

    • yes they are small, and I had a hard time wiring them. But they were the fastest I could find. If you find something that fast, they are good to use too.

      • Thanks a lot, me and some classmates are replicating your proyect for a class, we´ll send you a video once we get it going (hopefully we will) also, one final doubt, the primary and secondary need to be wound up in the same direction right? (also, is there a particular need for one direction or can it be either way)

        • Same direction winding is fine. In theory for this circuit it doesn’t matter which way. But same direction would have less voltage difference between primary and secondary, so less chance of insulation breaking and arcing. other wise either way is fine.

          • Thanks a lot 🙂 by the way, the capacitor that is the closest to J2, C9, with which polarity should it be connected? (sorry if it´s an abvious question, we are merely third semester atm)

  33. Ancient Wolf
    on October 16, 2016 at 1:32 am said:
    We love your blog, and your humor is so funny and great. My grandson and I always laugh at your videos. He is a high school student studying electronics planning to make your fabulous tesla speaker together with me.
    We are about to buy a used oscilloscope on eBay and could you help a fella out ? It has to be cheap and good enough to do everything needed to tune the secondary etc. Pleasssse?

    Reply ↓

    on November 1, 2016 at 8:42 pm said:
    Mehdi, Thanks for your quick reply to our question. It has been several weeks and we are getting very excited to get started. Once all the technical questions are figured out we are going to get going.

    We purchased a BK PRECISION 2120 2-CHANNEL 20MHz ANALOG OSCILLOSCOPE 50m/div-V/div from ebay and it is to be delivered today.

    Our next question is about the power supply, I noticed yours provides 300 watts at 32 volts. We are planning on building our own power supply like this one: Low Voltage Tesla/EHT Coil Driver Using SG3525 IC Supply 15V-24V , 10Amps Load; link found here:

    Could this one be altered to provide 32 volts and adequate power for the musical tesla like your power supply or could you suggest another design?

    And one more thing please, would we need a function generator to test for resonance and could we make one from a 555 timer? I understand that it can work from 1 hz to 1Mhz.

    Thank you so much, we are big fans of yours and watch all
    your videos.

    Reply ↓

    • Well if your tesla coil draws less than 5A, it should be good. Depends on your design.

      I think you can use a function generator to check for resonance. The resonance frequency would be the most voltage output loaded. I haven’t tried it though myself. The resonance highly depends on your design (inductor and top load) as well as environment. 555 might be too slow for the resonance frequency (like 1MHz and above). Unless your resonance is slow too.

      • Hello Mehdi,

        Thank you for replying, again.

        We have a few challenges and we are hopoing you can help out. Instead of using the “two volt Telsa Coil driver using IC3525” we purchased a buck converter from GROK. It is a 32 Volt 10A converter rated for 32V max. So we are rewirering a microwave oven transformer to power it. The problem is after rewinding the secondary for it using a ratio of 120 turns to 31 turns the output voltage is 34.6V AC with no load. WHen smoothing capacitors the voltage goes to 47V. Why does this happen and will this burn up the buck converter? Should we remove turns from the secondary or can you suggest something else to do? We have tried reducing the number of turns, each time we remove a turn the voltage drops 1V. Any suggestions you make will be greatly appreciated. Here is a drawing of our circuit.

  34. asdfdfafasdggasdfadfbyasd ahsdnyhadsfabjdfajdsfyandyadsbngasxd cbasdfbyxzcvnaxycab xzycha sdycasbcga7sxc axsycasbxctyzxbct gauxzc hzXycaB ZXyA XcyzxcbZY&xbcZXYcv zxcvabxcyzx cyuasdfnadusfahdf9iadsnfusdfnasdfuasndfasdnfasudfbhaydsfabsdfasdbfyasdfhnaysdfnasdyfasndfasdfhasydfbhasdyfasbndfyansnnao9sdpfaksdf nbasdfnadisfpoasdfbyasd8fjasdfuiasdfnafashdtfandufoasdfyasgdha7udsf0asndfuasbndfguadsbfuasdfjvgdvfabsdftasbdasdfhatdsfbaudsjfnabsdfkasbdfhjasdgfjashdfb8uasmiaxzsofas xcyasvtashagdfjadsufabsdgfb aaisdpfa[sd[f[pasdnfhausdbfiusdfhjaisdf[a=[sd[f[asdkfagsdfhagsdif-asdfnasgavxsyfahsgcabhscyansdf-ymhldfghoo09234v2649s0dsfhagdfbgasdfkiakidsfjjudsf

    • Sorry, wouldn’t have much time to check different components in detail. If your parts are as good or better than the parts list I provided above, you should be good.

  35. Forgot to add that the burns are from the arc hitting your finger. If you hold the shaft of a screwdriver you can put it in the arc. Since it’s high frequency it travels over your skin and you don’t feel it. But you have an electrical potential between persons, which can burn.

    Oddly enough this is explained by the electrical explanation of “skin effect”…

  36. Mehdi,.. Didn’t seem to find how much current this thing draws. Did you measure it? It would be nice, since I have to purchase a fet specifically for the project. I assume your design was 80 amps? If you take off the 16 amps for a %20 reduction (since you paralleled them) I still figure 64 amps. I find it hard to believe that your supply can handle that current (at least the one in the picture. 🙂

    Most docs on paralleling say don’t do it, pick a proper device. If I had something I’d try to rig it up also. Looks like a fun project. I just have to watch the frequencies so my ‘automatic internal cardiac defibrillator” doesn’t go off… That would suck.

    • It draws around 10 A at 30V supply, which is the limit of my supply. The issue is not the transistor current handling. The real issue is that when it turns off, the voltage across it jumps super high over 1000V and due to avalanche the transistor conducts and heats up a lot. That could blow up the FETs. I may adjust the design later for better and smaller FETs.

  37. Hello mehdi, I would ask You.
    Are the comparators must mcp6562?
    Because i try use other comparators like Lm393n it cannot drive my mosfets
    Please help me solve this

    Best Regards

  38. Hii…..
    I am going to make it.
    Can I remove u2 and u3 IC’s parts and direct input audio signal wia u5 ic to MOSFET driver ic?

  39. Hello Medhi, I´d like to know if the grounds are common or not, just to prevent it from blowing up haha, and are the number of windings exact? I´ve seen some videos and tutorials that say that if they are not exact it will not work, or is it becuase the thing you mentioned about tuning the frecuency??

    P.D: I accidentally posted this as a reply to another guy´s comment sorry.

    • Hi Gabriel,

      Grounds are common. But for best results you should route ground nicely, in a star fashion. The number of windings are not exact. There are some calculators that can show you what dimension and number or turns gives you what results. But at the end of the day, accuracy is secondary. See, number of turns and dimensions changes your inductance which combined with the top load, effect the coil resonance frequency. Which means you have to adjust your primary resonance to VERY ACCURATLY match the secondary resonance for this to work. With my circuit above, you have to adjust the circuit frequency to match the coil resonance. It can be pretty tough as you have to be very accurately tune it. There is a great advantage using a circuit like Slayer Exciter which self tunes to the resonance at all times.

    • Start with easier stuff and work your way up, man. There are some great tutorials for electronics beginners out there on the internet.

  40. Hi,

    I’ve built the oscillator part of the circuit but its frequency is not going above 20000hz, I’ve used slightly different capacitor and resistor values, does this make a difference?

    Thank You

      • I fixed it, the coil works but the mosfet gate driver and R6 are getting very hot and smoke after about 20 seconds. Do you know why this is happening?

        • What’s the power rating of the resistor you use for R6? That might be the problem. Also, are you using the mosfets from his parts list or do you use other models?

    • Mhedi,
      We love your blog, and your humor is so funny and great. My grandson and I always laugh at your videos. He is a high school student studying electronics planning to make your fabulous tesla speaker together with me.
      We are about to buy a used oscilloscope on eBay and could you help a fella out ? It has to be cheap and good enough to do everything needed to tune the secondary etc. Pleasssse?

      • Mehdi, Thanks for your quick reply to our question. It has been several weeks and we are getting very excited to get started. Once all the technical questions are figured out we are going to get going.

        We purchased a BK PRECISION 2120 2-CHANNEL 20MHz ANALOG OSCILLOSCOPE 50m/div-V/div from ebay and it is to be delivered today.

        Our next question is about the power supply, I noticed yours provides 300 watts at 32 volts. We are planning on building our own power supply like this one: Low Voltage Tesla/EHT Coil Driver Using SG3525 IC Supply 15V-24V , 10Amps Load; link found here:

        Could this one be altered to provide 32 volts and adequate power for the musical tesla like your power supply or could you suggest another design?

        And one more thing please, would we need a function generator to test for resonance and could we make one from a 555 timer? I understand that it can work from 1 hz to 1Mhz.

        Thank you so much, we are big fans of yours and watch all
        your videos.

  41. Hi Mehdi S,
    My friends and I are doing a very important school project, and we wanted to do it about the Tesla tower. We don’t know much about physics since we are very young (16 years). We wanted to use your Tesla circuit, for our school project, all credits will be given to you. Do you mind if w use it?
    Thanks in advance.

    • Hi Arturo,

      Of course you can use it. But a word of warning: It is a hard circuit to operate. I suggest you do the slayer exciter circuit and have some florescent lights glow. That one is super simple.

      • Hey Mehdi Sir
        same with me i am 15 years old and i wanted to make the tesla coil given above but looking at the circuit schematic life seems tough can you please provide me a similar schematic but a easy one so that i could make it. i only need the sparks not the sound so sir it’s my humble request please provide me with a similar schematic.

        your loyal fan/subscriber
        Shrijit jha

  42. Dear Mehdi,

    I have built the entire setup of the tesla coil part one. All the components are functional; I am seeing sawtooth waves, 5v waves from U3, 12v waves from U4, and the waves being produced from the MOSFET. However, I think that my ground wiring for the coil may be off. Every component is linked to a common ground. No sparks are occurring and the fluorescent bulb won’t light up.

    I am using a VSUP of 20v and 500mA

    Could you help me figure out what is going on?

  43. Is C9 a polarized capacitor? I know the other 10 uF are but C9 isn’t connected directly to ground. If it is polarized, how and why? Is it modulating the input from the audio jack? Thanks!

  44. Hi, what do you mean by:
    “Make sure the ground for the oscillator circuit is not supplied through power circuits (MOSFETs, gate driver).”

  45. Hi Mehdi, just a quick question.
    So are you using your full bridge rectifier on that close up photo of the circuit? Because I don’t see a few parts in the circuit diagram which are in the photo. I’m still working through and calculating the circuit to find why everything was put where, but in the mean time, if I create the circuit from the circuit diagram, everything should work fine(provided I don’t do something wrong :p)? Also the VSUP has to be able to supply 32V 10A? Thanks. (I’m thoroughly enjoying the videos as well, being able to apply and relate some of the knowledge I’ve gained from uni from your projects and videos is fantastic!)

    • EDIT:
      ok nvm, I see you said you tried to use your full bridge rectifier but can’t yet until you find a workaround to stop the mosfets blowing. So is a 10A VSUP a large enough current allowance?

      • I haven’t made the tesla coil yet, but I’ve run some numbers on it. V=L * (di/dt) so the MOSFETs can handle 1200V and can close in 40 ns according to their data sheet, so dt=40ns L is around 20 microHenries so plug that in and you get di = 1.7A so I believe that you only need around a 2A supply to get the best voltage from the inductor. So what voltage do you need? Well if you want to run at 1.5 MHz you need to charge the inductor every .67 microseconds, for no resistance the current in an inductor is I=(V/L)*t voltage divided by inductance times time. So for a current of 1.7A and an inductance of 20 microHenries to charge in .67 ns you need 51 volts. So a 50V 2A power supply is what I would think you need.

  46. salam.khaste nbashid
    aghaye mohandes mishe marahele sakhtesho kamel baramun bzarid ta btunim bsazimesh?age farsi bzarid k kheili khub mishe.age mishe baramun mail konid tashakoooor

  47. salam aghaye mohendes lotf mikonid terze sakhte in teslaro besorete farsi beram ersal konid khili memnon mishem.


  48. hi mehdi,
    why you connected the mosfet in parallel? what happen if i connect them in series?
    can i increase the voltage in this way?

    • ah sorry i have another question, i searched the capacitors that you used, but i didn’t find capacitors whit the same featuers, for example C7. Are you sure you have used these capacitors?

  49. hello!Mehdi~I am a Chinese children,I am just a 14 boy.I have made so men thing that can give me 1000V(DC),the energy was just from a common betters,as you see,it just have a little current.I just want to make a SGTC (a kind of simply tesla coil),so…what do I need,and what should I do?😊

    • any old transformer with no gfi (ground fault interruptor), some HV capacitors, a spark gap, and the primary and secondary coils. adjust the values of each accordingly.

  50. Hi,
    I have completed making the circuit with the amplifier but strangely enough i’m not able to get any arcs out of it. I used a 12v DC supply for the low current supply and have run VSUP at 7.5v and 16v. I cannot see any arcs at the toroid. The toroid is essentially an old Hard drive platter mounted on a large bolt connected to the secondary winding top. I can get a fluorescent to glow when brought near the coil so i guess only the slayer exciter portion of the circuit is working. The lamp will go on and off as i turn the POT1 through its range.

    can you help me identify what is wrong with the circuit? . The bottom of the primary is connected to the MOSFET and the top of the primary to VSUP . The bottom end of the Secondary is grounded and the top end is connected to the toroid.

    Any help regarding this will be greatly appreciated. Thanks.

    • The bottom of the primary has to be connected to vsup while the top to the fet.
      Also note that windings of primary and secondary should go on the same direction.

    • also be sure that the circuit is tuned at the resonance frequency of your coil, mine for example is at 1.5MHz despite mehdi’s one whas at 1MHz

  51. hi medhi ı wanted to make your tesla coil to my school project . ı buy the coil already every thing is OK. but ı cant under stand one thing what is the comparator? is it same thin with op-amp or not ı have some tl-72 and tl 84 op-amps ı can work with them? and ı cant find the mosfets in my local strores which type of mosfets can ı use? ı can dicrease the V sup for them. and what is your comparators name ı mean what can ı say if ı wanted to buy them ı goto electronic shop and just say? can ı say “hey gimme some fu#$ comparator m8” ı think if ı say that they hit me 🙂

  52. Hi,
    I am in the process or building the musical teslacoil and came upon a problem, the MOSFETs you have aren’t available to me so I wonder if this 1000V 6A 190W MOSFET would work instead. Part #: IRFPG50PBF
    It has some different characteristics than yours.

    Thanks in advance for your answer.

    • Hi!
      I can help to you!
      Buy IXFH16N120P mosfets wich is avaliable on aliexpress for 10$/4 piece.,searchweb201644_3_505_506_503_504_301_502_10001_10002_10017_10010_10005_10011_10006_10003_10004_10009_10008,searchweb201560_1,searchweb1451318400_-1,searchweb1451318411_6451&btsid=2481dcce-e60b-4736-a84a-94982bcf1bf8

  53. What kind of diameter (mm) pipe you used for the secondary and that’s pipe is how high (cm)?
    And what material did you use to the primary winding (10turns)?

  54. I’m really curious, in the spinning wheel scene, the electron jets were spinning the wheel counter-clockwise. Is there a reason for that direction? Could you alter it?

    • There was a similar demonstration in a physics lecture I had. If you look closely at the wire section that is put on the tesla coil, the ends are bent in opposite directions. The most activity is at the ends of the wire, and as such, the most push is in the direction the ends of the wire are pointed. The rotation could probably be reversed if the ends of the wire were bent the opposite way.

  55. Hey!
    I’m a huge fan of your work !
    I’m taking the Tesla coil as my university project and using your design as a reference.

    I have a few doubts, the power mosfets are not available locally in my country and i was wondering if i could use a different power mosfet with lower ratings for this project. Assuming i use a mosfet with 600v and 10A ratings, how will it affect the whole circuit. will it be safe to use it with this circuit or will it work at all.

    need your help on this 😀

    • Lower rating MOSFET would work, but you will have a more limited output power, so your arcs will be a bit smaller. Remember a continuous arc like mine is generally short. For longer lightning like arcs you would have to interrupt the arcs at lower frequency like 100Hz. And if you do that, those arcs would be much longer and so noisy and you can’t play music with them. Also visit for other circuit and tutorials.

    • I used 600V rated MOSFETs and added a 4nF capacitor between the drain and GND. basically, the problem is that when FET is turning off, all the 0.5LI^2 energy stored in the coil, translates to 0.5CV^2 on the Coss of the FET (~200pF) so the Voltage is huge. The added capacitor makes sure that the voltage wouldn’t peak above the FET reated voltage. You nead to calculate the peak current (I=V*dt/L) and then find the capacitance value. The problem with adding capacitance is the the FET will need to discharge is, resulting in mode power dissipation bet if the FET is fat enough and you have a good heat sink then you should be OK.

  56. Hi!!!! I’m Italian and I’m an your big FAN!!! You are a bit crazy but you are fantastic! 🙂
    Only a thing: With the jack (in the second cirquit), are the sparks as long as the first cirquit? Have you tried it?
    I hope You’ll responde me 😉 BYE BYE

  57. البته اقای مهندس توی مشکل دوم این پرسش هم مطرح هست که چجوری سایز کلاهک رو تعیین کنم سایز مناسب و درست کلاهک جهت افزایش بازدهی سیم پیچ تسلا مهمه … فک کنم سایز کلاهک به سیم پیچ ثانویه بستگی داره ولی محاسبشو اصلا بلد نیستم ؟؟!!نمیدونم شما بگید ،علاوه بر اینا دو تا سوال دیگه هم داشتم سوال اول اینکه چرا سیم پیچ ثانویه رو یک لایه میپیچن من میخوام مثلا 1000 دور بپیچونم بعد یه عایق نازک بزارم رو سیم پیچ از روی اون 1000 دور دیگه هم بپیچونم اشکالی داره ؟؟؟؟!!!!اما سوال دوم اینکه میخام فضای خالی لوله پی وی سی رو با یه چیزی شبیه فریت مثل پودر زغال چوب پر کنم اینجوری خاصیت القایی سیم پیچ ها بیشتر میشه ؟؟؟؟اصلا مناسب ترین چیز برای پر کردن اون فضای خالی چیه ؟ میخوام بازدهی سیم پیچ تسلا رو شدیدا افزایش بدم اقای مهندس میخوام یه کار درست حسابی انجام بدم لطفا کمکی بکنید. اگه اشکالی نداره فارسی بنویسید انگلیسیم اصلا خوب نیست! با سپاس فراوان

    • Bayad sanavie yek laa bashe, chon tafavote voltage beyn sim pichha kheyli ziade age ro ham bebandid beyneshoon jaraghe mizane va short mishe.
      Mamoolan havaye khaali bara Tesla Coil behtarine chon talafatesh kame va saritare. Mavade dige energy misoozoonan va sor’at ro kam mikonan. Baazdehi Tesla coil kollan eftezahe. Mohemtarin mozoo resonance ke age khoob tanzim she, bishtarin power biroon mire

  58. سلام اقای مهندس من میخوام یه سیم پیچ تسلا اما بزرگش بسازم ولی دو تا مشکل خیلی بزرگ!! دارم اول اینکه ظرفیت خازن مدار اول من باید 15 نانو فاراد باشد و بتونه ولتاژ 15کیلوولت رو تحمل کنه هزار تا هم خازن دستی درست کردم جواب نداد تو بازار هم از خازنای 1میکرو فاراد 430 ولت هست ولی باید 65 تا از اونا بخرم که 260 هزار تومن برام اب میخوره!!!! کلا برشکست میشم واسه یه ازمایش و البته باید سری ببندم هم ظرفیت معادل بیاد بشه 15 نانو هم ولتاژ بین اونا تقسیم بشه تا خازنا به فنا نرن
    اما مشکل دوم، من یه نرم افزار ” تسلا مپ” دارم اون بیشتر گیجم کرده تا کمکم کنه، گفته میشه اون کلاهک سرسیم پیچ خودش نوعی خازنه ولی چجوری ظرفیت اونو محاسبه کنم تا فرکانس رزونانس مدار دوم دستم بیاد نمیخوام کلا از نرم افزار محاسبه استفاده کنم فقط شما راهنمایی کنید فقط تو رو خدا یه راهنماییم بکنید خیلی به این در و اون در زدم تا شما رو پیدا کردم با سپاس فراون

    • Samaleyk, kheyli az mardom baa oon khaazen dastiya moshkelo hal kardand. Donbaale khaazene botry (bottle capacitor) begard mibini chejoori sakhtan.
      moshkele dovvol ro nemidoonam chejoori mishe hal kard. Kkhodam mohasebatesho balad nistam amma calculator online hast ke komak mikone. Dar nahayad kheyli aasoon nist. Bayad ba dore sim pich avvalie baazi koni ta tanzim she resonance avaie va sanavie yeki she.

  59. Hello Mehdi!
    Thank you so much for making your videos! I originally saw them when I was in college and now I show them in my High School Physics classroom; my students LOVE them! They are so engaging and educational! Please keep making them! 😀


  60. Hi Mehdi!!!
    I am love tesla and wireless electric.
    I am big fan.I want this make to tesla coil.
    You make and share please i am not know

  61. Hello Mehdi!!
    I’m 15 and I love electronics. I’m from Italy and I’m a big fan of yours!
    I want to make this circuit but I don’t know how to make the toroid and the coil: how much is the diameter of the copper wire? and how did you make the toroid?
    thanks in advance!

    • The top load toroid I made was pretty random. Its size would change the stray capacitance between the coil and surroundings. The combination of toroid capacitance and the inductance of your coil would result in the resonance frequency. There are some online calculators that would help you come up with the size of things. But you also need to know if your circuit can generate that frequency successfully.

  62. Hey, I am thinking about making this as an experiment. I was wondering how much money was needed to all of these materials, and maybe you could give me a list of websites where I can buy the supplies from. Thank you, and by the way I am always shocked by your videos (ba dum tss).

    • Including everything that would blow up once in a while, less than $200 and more than $100. You can get the components from But some warning, it is not an easy circuit to build and operate. Also it is high voltage.

  63. hi mehdi,
    i am an italian fan on youtube, you are crazy, but i love your video!!! xD

    can i use directly 5v instead of 12v, avoiding the use of the regulator?
    what is “VSUP”? where is it connected?
    the power mosfet (Q1-Q4) are connected in series?
    how can i understand the correct connections of U2, U3 and U5?
    sorry for all these questions, but i am not an electronic expert…

    • you need close to 10V so that you can drive the MOSFET properly. lower voltage results in not very well turned on MOSFET.
      VSUP is a second supply at a higher voltage like 30V to drive the coil.

      MOSFETs are connected in parallel.
      For ICs you need to download their datasheets and see their pinouts

      • Hi Mehdi! I actually wanted to know about the primary winding. What if in your model the coil is made helical instead of funnel type? And the VSUP is from a variac right?

  64. Hi Mehdi,
    I have recently built your slayer exciter circuit and am planning to build this Tesla Coil.
    Are there any negative health effects from being near the coils field or from touching the arcs?


    • I wouldn’t recommend touching arcs or being exposed to its radiations for a long time, because I am not sure if it is fully safe.

  65. My capacitor C9 is an electrolytic capacitor and I am not sure we’re the ground side or positive side goes and I sincerely hope it does not blow up.

  66. Salam,
    I wanted to ask if the top load is electrically isolated from the threaded rod or not? and will the Tesla coil work if the threaded rod is not isolated to the top load?

    • My top load is connected to threaded rod, but the rod is short and ends in the top wood. It doesn’t go all the way to the bottom. Rod and load are both connected to the secondary wire end.

  67. سلام جناب مهندس
    میشه ابعاد و نقشه ساده تر رو برام بفرستید
    میخوام درستش کنم
    یا حد اقل بهم بگید که از کجا میتونم به این اطلاعات دسترسی داشته باشه
    اگه این لطف رو بکنید خیلی ممنون میشم

    • Salam jenaab! Manzoor az naghsheeye sade tar ro nafahmidam. In schematicie ke man sakhtam. Modele saade taresh ro to maghaleye Slayer Exciter mitoonid bebinid. website ham ettelaat khoobi dare.

  68. hey mehdi.s first things first i love your videos but i would also like you to help me make the slayer circuit my 2n2222a transistor keeps heating and soon after blows up and iam not able to make the circuit work my circuit is a 12 volt circuit.should i buy a transistor of different number, please help . your videos are amazing and funny continue to upload more videos .

  69. سلام آقا مهدی زبان انگلیسی من خیلی خوب نیست میخوام بدونم علت ایجاد آرک در بالای سیم پیچ ثانویه چیه میتونین یه توضیح مختصری بدین؟

    • ولتاژ روی ثانویه انقدر بالا میره که شارژ الکتریکی رو به هوا و فضای دورش میپرونه. کلا دلیل پرش ارک ولتاژ خیلی‌ بالاست.

  70. Hi Mehdi,

    Thanks a LOT for the help you have already gave me, I managed to build the “beefed-up” version of the slayer exciter with 12v for the control circuit and 24v for the primary. I would like to ask a small favour from you. I want to build this circuit of yours and I have trouble finding just ONE part. I have tried sourcing many MOSFETS and also stores, online or local, but I have not found the SCT2450KEC. I am not sure what it can be substituted with and I thought if I should ask anybody, it is you. I mean, seeing as you know more and are more experienced. Thank you very much.

    Yours sincerely,

    P.S. As you used 170v VSUP, can I use 100v VSUP?
    P.P.S. Does 2SK956 MOSFET work?

    • Oh yeah, I also got a DIP dual-comparator so I am not sure if I got the wrong one. I mean, some people are complaining about soldering comparators like yours.

    • I didn’t use 170V VSUP! It will blow up the MOSFETs if you do! I used 30V, you could go up to 50V. It might work at 100V at very low PWM.

      The transistor is not too bad. It’s RDSon is a bit high and the VDS maximum is lower than what I have, so it may not be able to take much power. Use with caution.

  71. what’s the diameter of the primary and the torus? do you suggest using 28 awg or 38 awg? i would love to make a coil just like yours (in turns of the coils, lenght ecc… i would also like to be able to touch it) but i don’t know what’s the max A for the vsup? should i use a 1,5A or a 0.1 A supply? sorry for bad english

  72. Hello Mehdi. Thank you for your videos. I have duplicated your circuit on a breadboard and my VSUP is 36 DC from a wall charger. I got the tesla coil to work but when I connected my 170 DC volts that is rectified from a 120 AC volts just like your full bridge rectifier, the tesla coil did not work anymore. I realized that my SCT2450 transistors are probably burnt. When I put back my 36 volt charger the tesla could barely works but when ever it works, resistors R5 and R6 get extremely hot. I have 2 fans; one blowing on the circuit and one pointing away to take the heat out of the circuit. Would you please tell me how I would prevent my transistors from burning again?

    I appreciate your help and time,

    • Don’t use the 120VAC as source! 36V is fine! higher voltage would blow up your circuit. your 12V supply, how good is it? Make sure it can provide enough current and put capacitors close to driver and connect them to driver with decent thick lines, so that the 12V doesn’t dip, otherwise things get quite hot. MOSFETs for sure will get hot. Put them on beefy heat sinks.

      But the main problem with this circuit is tuning the frequency for highest voltage. Unlike the Slayer Exciter that self tunes, this one doesn’t. Make sure the environment around it is fixed, then very precisely tune it until the sparks fly. Tesla Coils are tough circuits to build.

      • My 12 V is a regular wall adaptor. My signals are almost consistent with minimal amount of noise. I am measuring the output right after the 2.7 ohm resistor and it looks like it has no noise at all. Just square waves that can be controlled by the potentiometers. But my problem still consists when I can’t get continuous sparks. I checked my whole circuit. Plus since I am building this at a university, some of the professors are interested and try to help but they don’t have all the time that I need. Therefore if you would please post a video of you measuring the signals with your oscilloscope at different spots on your circuit would be greatly appreciated.


  73. Hi Mehdi !!
    I’m new to your YouTube channel and website, and the more I browse them, the more it amazes me 😉
    But I have some question :
    – Why does the frequency of the Schmitt Trigger Oscillator doesn’t change in a circuit simulator software ? Did you use black magic to make it work in your circuit ?
    – Is it possible to replace the Schmitt Trigger Oscillator with a microcontroller to generate the desired frequency ?
    – Is it possible to use a step-up “boost” DC-DC converter to generate 32V for the Vsup ?

    Thanks for making all these projects and making them open-source !!
    Greetings from Belgium !!
    Frédéric Druppel

    • Hello!

      – The schmitt trigger frequency only changes when you change POT1. Changing the feedback resistance changes the frequency. If you provide fixed values in simulation the frequency wouldn’t change of course!

      – Yes it is possible. You just need to make sure all the radiation from the coil doesn’t mess up the micro. It radiates a lot! Shielding is important.

      – Yes, you can use a DC/DC switcher, just that it also needs to output close or over 10A of current depending on how much you output.

      Have fun!

  74. Hey, would you tell me how much current this uses (input just before the rectifier). Also could you give me the layout on your hand soldered board, like what goes where and where do I connect which part. I’m planning to make one of these and need to finish getting the parts and make a circuit board.

    • Lemme clarify what I just asked, how much current is being drawn by the control and power circuit. I just noticed where there 2 different circuits in one.

      • The control side doesn’t take much current, maybe less than 100mA. But the power to the coil takes close to 10A.

        I don’t have a layout of the circuit at the moment. I should sit down and draw things.

  75. Hi Mehdi,
    I also want to make one tesla. I have a question. I have 230V AC, can i use this voltage to this project or should I transform it to 110? Also can you tell me parameters of your pipe for secoundary winding.

    • Well, like I said in the article I ended up not using my full bridge rectifier because the rectified 120V was too high for my circuit. I used a power supply around 30V. So you need to step down your 220V.

  76. Hello sir,great work! I have two questions 1)Is it possible use a high voltage diode in reverse bias across the primary (reverse bias from Vsup) to prevent the mosfets?and 2) Can igbt used in place of mosfets?

  77. Is it possible use a high voltage diode in reverse bias across the primary (reverse bias from Vsup) to prevent the mosfets?and can igbt used in place of mosfets?

  78. Can i use a high voltage diode in reverse bias across the primary (reverse bias from Vsup) to prevent the mosfets?and can i use igbts?

    • Not really. It makes arcs, but Tesla coil voltage is much higher and its resonance frequency is much faster. So it is different. You could use that to drive the primary of a Tesla coil.

      • oh btw, i’ve read a fact that if we use voltage multiplier, the current will drop and the voltage will increase. Is this possible more than 10kV Voltage with low current can make a big spark??
        If it can, i’ll use voltage multiplier that can make an output about 10kV, connect series with spark gap and the primary coil.

  79. Wow good job! That voltage is applied in Vsup? And also, the signal on Vsup is AC or DC, I did not understand if you use a regulated power supply, or if you use a sine wave signa

  80. Hi Genius,

    I am having one million dollar question..? IS IT POSSIBLE USING TESLA MY TORCH LIGHT BULB GET FUSE or ANY BULB TUNGSTEN make disable…?

  81. Sir, i used the circuit from mosquito swatter and connect it to the spark gap, and then, i connect it to the primary coil.
    The mosquito swatter circuit i used, use 4,8 V battery. There was a NPN transistor, 1 small led, 2 piece of 1,5k ohms, transformer, 4 piece of 3kV capaaitor, 4 diodes, and 1 piece of 2kV capasitor. if i change the input to 12V battery, do u have any idea how should i do to the circuit without broke the circuit? What components should i change? Thanks sir

  82. Hey mehdi nice work! Is there any other ic which can be used in place of mic4452? Or can i eliminate that ic and connect the output of the square waves to the gates of the mosfets?

    • You need that IC to drive high current and fast. But I don’t know of a replacement at the moment. Unless I do some searching… which you could do!

      • Thanks man! I made the oscillator part. Since i dont have a oscilloscope,i connect a LED across the output of oscillator,the LED first lights up and then decays. Is that supposed to happen? If no then what can be possible problema im using lm358 in place of mcp6562

        • If you use an LED you won’t be able to keep up. The LED will flash far faster than you can see. This is because your using about 1MHz, which is far faster than the eyes or brain can process. You will need something to measure the frequency or borrow an oscilloscope. As far as the LED decaying, I would assume that is the LED dieing. LED’s can only take about 3v and your connecting it to about 5-12v which will kill the LED.

          Hope that helps.

          If someone finds a mistake in what I just said then please let me know, thanks.

  83. Dear mister Sasaghdar,

    We’re high school students from the Netherlands and we are making this circuit for our final year project. However we’ve encountered a few problems. We hope you might shed some light on (some of) these problems:

    – Made the Slayer Exciter and connected it to a 1500 turns secondary and 10 turns primary but we are unable to make it function properly.

    We have observed and measured the following at 10V and 0.03-0.05A
    * The diode, transistor and resistor of the circuit seems to function properly
    * The voltage across the positive supply and the positive side of the secondary (input) is measured to be 9.8V
    * There is no voltage applied across the primary coil
    * We have measured that the voltage across the top load and positive side of the battery to be 9.4V
    *Diode does not blink/turn on
    * No sparks are seen and fluorescent light bulbs/LEDs do not light up at the proximity of the coils when the circuit is turned on.

    Both ways of connecting the primary are tried out but to no positive result and we have also chafed the ends of the coils with sandpaper to remove the insulation.
    The bills of material:
    – 22k Ohm
    – 2n5550 transistor
    – 1n4148 diode

    Furthermore, we are also trying to replicate y own circuit on this article of yours. However, when we were trying to connect the comparator it quickly became clear to us that it is very hard for us to solder the ends of the components to the comparator as it is just too small. We are aware that we need a some sort of IC fitting to install it properly, sadly we are unable to find a fitting one. May we ask you what kind of IC socket you were using?
    We hope you may be able to help us.

    Yours sincerely,

    Sam L.

    • Hi Sam,

      You cannot measure the voltage of the top load with a meter. As soon as you touch it, the circuit stops working. Because you would load it significantly and effect its oscillating frequency. So make sure nothing is connected to it externally, then bring your lights close and see if they turn on.

      Make sure all your connections are correct (diode direction and such), it should work, unless your secondary and primary dimensions are way out!

      For the comparator, I soldered wire-wrap wires to its legs and connected them to my circuit. It wasn’t too hard as the wire was too thin and I’m use to it. Also there are some board like the one in the link below you could use:

  84. hi Mehdi
    great work love it all and very help full thanks

    i just want to know what to i change to get lower freqeuncy .my resonant is only about 200khz

  85. Hi Mehdi,
    I have a school science fair project coming up, and I thought I could build a tesla coil like you did. Since it’s going to be at school, is there some way I could limit the amount of power to the circuit? Also, I live REALLY far from any electronic parts stores, so where do you think I could get supplies for this? BTW, your videos are hilarious and informational. Keep up the good work.

    • Hi Jake

      If you use a power supply, it would be easy to limit the power of the circuit by just lowering the supply voltage. Also as mentioned in article above, you can adjust the output power by turning one of the potentiameters. if you leave in US, I suggest you buy components from where they deliver the next day.

  86. -how many turns is you secondary coil? does it have an effect on the audio if it was about 1500 turn?
    -i live in Iraq so the ground wire does not exist? what can i do ?
    -what is POT2 & POT3 for?
    -could you please take more pictures ,would love one with you pointing the parts, specially one upside down?
    -could you explain what are the voltage supply that you used? cuz i see the full bridge rectifier and it produce 170v as you said , did you convert it to 32v and used it as you VSUP ?and if so how did you do it ,did you use voltage divider method by using resistance ?
    – in my country we have 220v AC about 290 – 300 v DC i was thinking to use voltage divider to make it as32v VSUP but do i neet to filter it with an inductance?
    – the 12v source could i use the cell phon charger ?
    -can i use more MOSFETs’ i was thinking about 5 or 6 of them ?
    -tuning the circuit’s frequency is done either by a spark gap or changing the POT1 right?how do i know if it’s tuned ?

    • With the questions you are asking, it is obvious you are just starting out and this is not the circuit to start with. Try doing some smaller circuits first, to get a feel for how electricity works. Though he jokes around in the video, this is some serious voltage, and could easily kill you. For your own safety, you need to be able to answer those questions on your own, with confidence, before you even start to attempt to build this circuit.

    • Hi Mehdi,
      I’m in electronics 12 (High school) and am trying to make a coil like yours. I want to know if it’s safe for me to do it. Judging from what’s in the article, I don’t think it’s too dangerous. But I still wanna be sure. Also, how much do you think the whole project will cost?

      Thanx 🙂

  87. Hi Mehdi,
    Sorry, backtracking to the Slayer Exciter article, I was building the simpler circuit for fun as I could not find the Gate Driver IC chip but nothing happened, even when I brought a flourescent lamp close. I was driving the circuit with 9v but when I raised it to 16v, the transistor started smoking so I replaced it. Even at 12v, nothing happens.

    • Have you double checked your connection? Did you try flipping primary connections? Is your transistor a proper one? I need to see it up close!

        • Hi Mehdi,

          Sorry for troubling you but here are the pictures:

          (Paste the link into your address bar.)
          Also, in the pictures, the transistor is a 2N2222 one, and the yellow alligator clip and the green wire is connected to the secondary coil’s ground while the white and black wires are connected to the primary. The diode is a 1N4148 one. The resistor is 22K Ohm. I only used my power supply when the 9v battery did nothing. I plan on swapping the transistor with a BD135 transistor.

      • Hi Mehdi,
        I’m in electronics 12 (High school) and am trying to make a coil like yours. I want to know if it’s safe for me to do it. Judging from what’s in the article, I don’t think it’s too dangerous. But I still wanna be sure. Also, how much do you think the whole project will cost?

        Thanx 🙂

  88. Hi Mehdi! Brazil here man!!
    Great Project. I have a couple questions, the biggest capacitors (in the pic of your built circuit), what’s the value of them?
    When i build this driver, i have to use transformers, like in a normal SSTC, or just the driver do the work?
    And i would like to point something, these MOSFET’s in Brazil are tough to find!

    • He used about 2.2 mF, look at article about rectifier. And what transformers? Did you mean transistors? If yes – the answer is yes, driver just makes transistors work better. And you don’t have to use those specific transistors, just any with good specs, use your local equivalent for Ebay. (I’ve heard about high import taxes in BR, so you may be better with parts from local manufacturers)

      • Thanks man! I was talking about a normal SSTC, where you use something to give you a “burst” and a tank capacitor. Yeah, i was looking in Ebay and the taxes were kinda high.

  89. Hi Mehdi, thanks again for all the help you gave me before. I want to ask you one last question: I was looking for components to buy, unfortunately I couldn’t find C7 (100pF capacitor) because the size is too small. The question is: where did you buy yours? Can I use a bigger capacitor like a 10uF 20V cap or is that too much?

  90. Hello Mehdi, I’m thinking about using TVS diode, like you said in a comment ealier. I’m planning to use 320v to supply transistors, and 400v diode. I got good cooling for MOSFETs, but I’m worried about this TVS diode. Similar size components can survive 0.1 to 0.5 watts. Will it work in air, or should I try putting it into distilled water (with isolation of metal connectors)?

  91. Hi Mehdi, I’m planning to build this beautiful piece of engineering but I’m new to electronics so I would like to ask you a few questions to clear my doubts. First of all, what is VSUP (near the primary coil)? How do the 2 circuits on top connect to the main ciurcuit? Is J1 a spark gap? The circuit that contains U1 has 2 supplies, 12V and 5V, right? What is 12V DRV (in the top right circuit in your diagram)? Does the secondary coil have to be connected to ground? Can all the ground connections be connected to the wall ground?

    • – VSUP is a DC supply voltage above 20V
      – All nets with same names connect to each other
      – J1 or J2 are connectors. J1 is where 12V supply connects to and J2 is the audio jack that plugs to audio port.
      – U1 is a regulator, that has 12V input and generates 5V output
      – 12V_DRV is a filtered 12V that supplies the gate driver IC
      – secondary can connect to ground, earth or VSUP.
      – Yes they can, they don’t need to though

  92. Hi, I have built the circuit, but when I run it, it has bearly a spark even at full power. I try to adjust the frequency, but nothing really happens, and I can even remove the trimmer and it will still run the same. Furthermore, when I inverse the polarity of the primary, there is no change, just the same spark. Help greatly appreciated. Thanks!

    • Try to keep you DC connection to primary and secondary at the bottom of the coils. Tuning the frequency can be pretty hard. Make sure you know the resonance frequency of your coil and tune very gently around it. Also when you tune, you must have a needle sitting on your toroid so the sparks can jump out. At our power levels there won’t be any spark without the needle. Good luck!

  93. Hi Mehdi, I have built the circuit but I am having problems with it. I soldered it all together and then tried it out the first time and U3 started smoking.I replaced U3 and I Looked at the circuit and noticed that U2 did not have a ground connection or a connection to 5 volts. Also I realized that U5’s output was not connected to the + input of U3. I fixed all the things i saw and It still didnt work. So then I went to the 5v and 12v regulator and rebuilt that.Not knowing I hooked it up wrong putting the 5v on the 12v rail, I tried it and U2 and U3 got very hot. Should I just replace all of the ic’s on the board (because they may have been damaged) and try it again?


    • Hi Max, look at their datasheets, some can take higher voltages and can be OK. The way I would build a circuit is step by step. Like I make the supplies and see if they work. Then put oscillator circuit together and see if it functions, and so on. That way you can catch things earlier without blowing all your circuit! Good luck.

      • Ok, thanks. I looked at the data sheets and tested the comparators and they were indeed blown. I ordered new ones and they will be here soon. thanks for the help, Hope ill get it working :p

  94. Hi, I built the circuit and everything was running fine, then all of the sudden it stopped working. The transistors are ok, and the driver is fine. The only thing that I can think of that could be broken is the comparator. Is it possible to break them on this circuit? Please help me I am really confused. Thanks

    • They usually don’t break that easily. Bring a florescent light close. Does it try to turn on? It might be that your frequency is out of tune. It is a hassle to keep the frequency in tune for arcs to jump.

    • I know! Those transistors burn easily. Your voltage is too high for a slayer exciter. Usually there are no arcs coming out of slayer exciter because its PWM duty cycle is small. Or you have to raise your voltage which means you have to pick transistor that are 1000V rated.

  95. How many power sources should i have to use in this circuit ..??
    what terminals are connected to the primary coil..?
    what is POT2 for??
    do i have to tune the frequency everytime??
    reply please.. i am doing this as my project in my college

    • Two supplies: VSUP and 12v
      VSUP and MOSFETs connected to primary. VSUP is a DC voltage that acts like AC ground.
      POT2 adjusts the initial duty cycle.
      With this circuit, if your environment around coil change large enough to effect the resonance frequency of the coil, you will have to readjust the frequency, other wise no.

  96. Hi Medi,
    tried out a simmilar tesla coil.
    As an oscillator I used a TS555 which can go up to 2,7MHz instead around 500KHz like the NE555.
    However the pinout is the same…
    I use 9V to power the TS555 and made a half bridge with two transistors: one npn and one pnp (often you see BD140 and BD139 because the can handle higher powers but actualy other npn and pnp work as well I found out) the power mosfet gets 30V at 500mA. It lights a lamp pretty well but i don’t have any streams 🙁
    Do you think i should look out for a stronger power supply which handles more current? As I read above some use currents around 1A to 5A…

    • It usually consumes lots of current. Also you need to tune your frequency very accurately. Bring a wire close to generate stream, then tune your frequency with wire present and at some frequency you may see it. Also make sure your PWM is 50% or a bit more.

      • Hi Mehdi!
        My coil works! I am not getting that thick arcs but eventually two streams come out of the end wire.
        My Vsup is 20V. I use a Laptop adapter as power supply.
        It can deliver 20V and max. 4,5A.

  97. I’m studying E.C.E b-tech 3rd year in India, my college conduct mini project competition and we want to do Tesla coil as a project we want a circuit for both wireless power transfer as well as music generator by connecting to a 3.5mm jack directly to a phone. Please send circuit to my e-mile before 20- Aug-2015. Please help me.

  98. Hi Medhi, would the MCP6542-I/P comparator work also? I’m wondering this because I have assembled the circuit, but it does not seem to be working, and that is the only part that is different from your schematic. The most the circuit does is flicker a fluorescent bulb right next to the toroid. Any suggestions would be greatly appreciated.

    • I see this chip’s propagation delay is 8uS maximum, which means it can be as slow as 62.5kHz. That’s very slow. You need something that can do well over 1MHz.

  99. Hello,
    Can you please send me a schematics of your Tesla Coil Solid State Driver with Audio. Made with Eagle,Tina or with other schematics maker program.

  100. Can we add a diode in parallel to gate an drain of mosfet to prevent it from going into avalanche region, when primary coil voltage pushes current into it.

    aren`t there reliable and fast diodes available for those current spikes and high frequencies.?

  101. Love the videos! 🙂
    But i do have some questions…
    Can you explain in more detail what is the purpose of using a gate driver, what would happen if you’d drive the MOSFET directly without it?
    Also can you also use 555 timer instead to generate PWM square wave (and would you also need a gate driver in that case)?

    • Gate driver is needed so that the MOSFET can switch quickly especially at high frequency. The reason is that MOSFET gate has capacitance and so driving it with limited current, it will take a while to charge and it slows down the MOSFET switching time. A gate driver can supply high current at fast speeds that helps the MOSFET work at high frequencies. You could use 555 timer, but still need a gate driver.

        • not really, you need a push pull configuration (npn and pnp) to drive high current both tuning the FET on or off, and even that needs to be designed properly to be fast enough. Why don’t you want to use a gate driver? That’s tested and works well.

  102. Hello Mehdi,
    What speakers can i use with the amplifier circuit? I been searching the web for one with the lm358 i just cant find one!

  103. Hi Mehdi,
    I tried building your circuit, but whenever I turn Pot1, it does nothing and my vsup draws no amperage. What would you suggest doing?

      • Do you have a scope? Can you scope your signals? See if you have proper PWM at the gate of MOSFETs. It is hard to troubleshoot the circuit without having a scope. Otherwise you can just double check all your connections and hope for the best! But if you have a scope, you will verify everything quickly.
        For ease of connection, I suggest you connect the ground on the secondary to VSUP instead (AC ground) and both VSUP connections should be on the bottom of both windings. Connect the MOSFET drain pins to the high side of primary coil.

        • Ok thanks that does help, unfortunately, I don’t have a scope. Ill have to fly blind. Just one last question. For the source on the mosfet, and the ground of the driver, where should I ground them if they should be separated from the oscillating circuit?

          • ground of the driver and FET sources connect together, and directly connect to the supply, rather than going through the ground path of oscillating circuit. They all eventually connect to the same ground, but their grounds branch right from the supply, rather than running series to each other.

            • Hey thanks again, do you think it is possible to add audio to the earlier npn based slayer circuit? I use a more powerful transistor, the mje3055t, and can achieve input voltages at 24 volts for a minute or so without it getting too hot.

  104. Hello,
    Does anyone know what are dimensions of the primary and secundary coils? Namely, the number of turns and the size of the toroid. Thank you!

  105. Hi Mehdi! I’m a Chinese boy and I really appreciate your works.Your videos always teach us in a fun way.
    As a Chinese middle-school student , I’m not good at English.But I have some questions and opinions about Tesla coils to discuss with you.
    First,I wonder how your coil plays music.Do you use a PWM system to turn audio frequency into square waves to control your coil?
    Second,I think you can use a Class-E structure instead of your single forward converter with 4 parallel MOSFETs.This may ruduce heat quantity from your MOSFETs and improve the productivity of your system.
    Well,in fact I think you can make a BIGGER secondary.With a lower frequency,you can use a FULL BRIDGE CONVERTER(or a half bridge converter,because usually they don’t work well at a high frequency.But I believe they can still work at 1Mhz,with a fast driver like IDDX415 and a gate-driving-transformer.) to drive your primary coil.In that case, you may achieve a higher power and get longer arc!LLC resonance structure can even be used to make a large primary current—–and IGBTs are better then.You used a amplifier to build a oscillator.But I think using a VCO in a CD4046(or a 74HC4046) is easier.A CD4046 can also be used to build a PLL system to catch the frquency of a secondary so that a oscillator is not necessary
    It’s really hard for me to type so much in English.Maybe I’ve made many mistakes,please don’t get mad!I’m also a fan of tesla coils.I’m looking forward to hearing from you.

  106. Hi again Mehdi 🙂 worked some days at my coil,nothing worked too well… my mosfet driver at the slayer exciter and at the music circuit is working well when i power the circuits and no load ,is workng well even when i connect a coil and do the appropriate calibrations with the potentometers,but once i close up a metal object to the coil to make some sparks,it heats up in 5 second and boom… i also made some new pcbs,one with another design( different resistors,mosfets,etc) from the web but notting good,it’s heating up and it doesn’t work. then because i’m stubborn i made another coil with 1400 turns( my first one was 700), tried different reistor values and the same happened there. the only circuit that worked fine was the one with the transistors,where i made some crazy experiments with 8 power transistors i found in the attic to make some nice 2-3cm arcs, but only that worked. looks like 5 pcbs with the mosfet drivers didn’t worked at all, and i think something is missing here… but what? any way at least im happy that i learned some cool stuff in these two weeks of experiments,but for now i will take a a break from this project since it’s past my knowledge and i invested too much money and time in it. wanted to use my music tesla coil for the project at my school that i just finished today,engineer in electrical installations. the power transistors made a great impression btw :). If you have some clues what might be wrong,let me know,ill take note for the future when i will reopen my work with the tesla coils :). ooh,and dont stop on making videos 🙂 i love when you get hurt! but stay safe. also include more details about everything when you write the articles,sometimes these details helps us novices to understand better how the circuit works and how to build them. Thanks. Have a great day!

    • Thanks for the comment, I have limited time to read and response and provide details. My articles and data need some level of knowledge. It would be hard to include everything to teach full electronics!

  107. I’m in Europe and that makes me very lucky. If I use lets say 6 of those transistors and attach them to CPU cooler(s) with fan(s) and pass 560V [230*sqrt(2)*sqrt(3)] DC (6 diode rectifier) electricity from 3-phase grid would it work? (I mean I’m sure rectifier will work, just will transistors handle it?)

    Also I made fm transmitter from Rasperry PI, and can I somehow boost the fm antenna signal? (transistor, op-amp maybe?) Also DIY fm transmitter is a great idea for video.

    • Two more questons: Can I just blindly adjust the potentiometer untill freqs are synchronized? (no scope, sadly)
      And how accurate must frequencies be synchronized? Lets assume the frequency of coil is 1 MHz so what range of frequencies would work?

        • I think IGBTs shouldn’t be used at more than 200khz.A mosfet wuold be better at 1Mhz.
          It’s not necessary to make freqs synchronized.But you shuold try your best to make them almost the same to let the resonance system work better

      • It might break your circuit if you go bling. it would be nice to measure frequency somehow before hand. If you have to, use smaller voltage, like 10v and have a florescent light like 10cm away, keep slowly turning until it turns on, then you are close enough and can raise voltage and go from there.

        The frequency needs to be pretty accurate, like within 5% or better for maximum voltage.

  108. Hi , you say you are having trouble with the FET’s blowing up from the large back EMF (VDS) produced when the PWM drive turns off. Would a high speed damping diode across Q1-Q4 D-S work ? (anode to ground, cathode to the bottom of primary winding) Or would that kill the operation of the transformer ?

    • .. or for that matter a fast recovery diode across the primary winding itself ?
      (sorry for double post , thinking as a go along here)

      Thanks for the videos anyways – hope to see more soon 🙂

  109. Hi. I ask if it would be any change if instead of tooth osilatorja use a sine wave oscillator as Robinson oscillator ?

    • You can, but then the PWM duty cycle versus the DC voltage level would be much more non-linear. So that might distort the audio more.

  110. Medhi, your work is amazing! Thank you for so generously sharing it with us!

    I made the slayer exciter circuit a few years ago, and I have been itching for a more powerful output. This circuit looks very nice and well thought out.

    A few questions:
    – How would I find the resonance of my coil without an LC meter or an oscilloscope?
    – Would two 12V 12AH batteries work for the VSUP?

    Thank you!
    –Michael Gardo–

    • The batteries’ voltage will be very very close because I don’t want the internal resistance of one messing up the current being drawn. If that idea for VSUP sounds bad, are there any other alternatives that you know of besides a nice power supply like your own? They cost an unholy amount!

    • 1) for finding the resonance frequency, use your slayer circuit and when it is running, measure the frequency and that’s it
      2) If you put your batteries in series to get 24V, then they won’t effect each other
      My power supply is pretty cheap, less than $100 I believe

  111. Hi, I was just wondering if you could post a tutorial video on how to make the circuit. I was also wondering how much all of the materials needed would cost.

    • Sorry, I don’t think I will make a video on connecting bits and pieces. That’s not really the type of video I create. All the material should be less than $150 maybe less.

  112. Hi Mehdi, thank you for your time to write this article,its very interesting how you carefully planned your circuit. Great job! I have a question… i found almost all the parts i need to build your circuit ,i used some equivalents of your circuit : TC4452VPA for the mosfet driver , a regulator L7805ABV and a 3006P-1-103LF multiturn 10kohm potentiometer. But i cant find the power mosfets SCT2450KEC. I found some equivalents but they are too expensive for me. Can i use more weak mosfets in parallel instead of 4 power mosfets? like 10x 4A900V ? I can only buy electronics from TME in europe. Thanks!!!

    • And btw… what is the minimum safe distance for electronic devices like cellphones/laptops? I’m a little afraid that when i will power it on, it will fry my phone it he pocket or it will cause a major blackout in my neighbour.

      • A reply will be good 😛 … Well, i finished yesterday the primary and secondary coil, and made a test with slayer exciter ,works fine 🙂 and finished just now the pcb with the OpAmp (permanent markers and FeCl.. ). It was a little hard to learn how the ICs worked and associate the pins with this diagram 🙂 took me 5h. I found a 5V and 12V wall adapter and a 26V6A transformer with a rectifier and caps. i dont have a more powerful transformer but it’s ok since i have 900v5a mosfets,the 1200v10a are too expensive(and i can only buy 1500v+). I didnt understand what was C9 ,an electrolytic or non-electrolytic capacitor, found that it was an electrolytic one with the positive pole towards the audio input,i dont have experience with audio stuff… the J2 is an audio input with a ground and L or R channel. do i need to choose one channel to be amplified by the OpAmp or i can connect both channels?also the audio ground must me connected to the OpAmp ground? also the 5v ground is separated for the oscillator circuit,and the 12v ground is common with Vsup ground i suppose, since there are mosfets connected there(someone correct me if i am wrong). it matters if the primary bottom is connected to the mosfets or Vsup? what about secondary bottom? Well,too many questions 😛 ill se if i can make this speaker to work,i done a simpe audio speaker with a flyback before but this one is a little more challenging 🙂

        • DAMN IT….looks like my R6 and my 4452 is heating up..dont know what might be wrong. when i plug in the 12 and 5v wall adaptors,these 2 start to heat till they pop like popcorn. the pcb is ok,triple checked. and everything is like in the schematic. is because i used an different mosfet driver,an equivalent one ? ill try to change these 2 pieces,recheck the datasheets and pcb,hope ill find some luck,since nobody helped me.

          • I believe one or more of your MOSFETs can be dead killing R6 and U4. This happened to me many times. Rmeove R6 and U4 and measure MOSFET gate to ground. If it is shorted, replace the damaged one by disconnecting all gates and see which one is shorted to ground. And only when all your FETs are healthy, replace R6 and U4. You should know what your resonance frequency is using the Slayer circuit. So first, don’t turn VSUP on, but turn your circuit and driver on. Make sure your oscillator is working all the way to the input of the driver, and see that your driver has an output, driving the gate of FETs. Check the voltage at the gate of FETs and make sure it is nice looking with a scope.
            Now that you are sure all your circuit works, tune the frequency to the resonance frequency, and only then turn your VSUP on. Lower your PWM to 10%. Bring a florescent lighth close and see if it lights up. Have an eye on your power supply current. With a wooden and long screw driver very gently adjust your frequency until you see maximum brightness on you light. Now that VSUP is on, you can’t scope anything anymore, because it will effect your circuit. Make sure you only touch your circuit with insulated material or it can burn you. when tuning frequency, stay around resonance frequency and don’t go far or the current may rise drastically.
            When you are done with your light, put a needle on the top load, and raise the PWM to 40%. Slowly fine tune the frequency again trying to see the sparks flying out. Hopefully they will.
            I don’t know how high you can go with your MOSFETs if their voltage is lower. high PWM can stress your MOSFETs and kill them with high voltage. Don’t keep them on for too long. If you see sparks, then you can raise your PWM to 60% and see them grow. You can also raise the VSUP, until your FETs, R6 and U4 blow! Otherwise keep them small.
            Now that you have arcs, carefully connect your laptop and play music to your circuit. You may have to fine tune your frequency and such to get less noisy arcs so that you can hear your music. Bring a needle close to the top load for more sound. Good luck!

        • Good job finding what C9 was. J9 is a mono input, a ground and a signal, not left and right. So just connect one. All grounds you see in the schematic are the same ground and are not isolated. Just route the ground properly, one line from your source ground to your oscillator and amplifier circuit, and another line to FET driver and FETs. The primary bottom best be connected to VSUP and MOSFETs to the primary top. The secondary bottom can also be connected to VSUP for ease of wiring.

      • It will not fry your devices unless you arc to them directly. They may not function correctly though if they are too close. But as soon as you turn it off, the device will come back to normal life.

    • Hi Arth, couldn’t find the datasheet of the MOSFETs, But in general make sure their VDS is high (>1000V) and their RDSon is low. If your RDSon is high, you need to put more in parallel, or also as a second option you can much better heat sink with a fan, and run it for short periods on time.

      • Great 🙂 thanks for the reply! i checked the pcb again and i think i’m ok with the grounds. i can connect the mosfets source with the mosfet driver ground and the 12v ground,right? i used six STP6NK90Z. i’m not planning to run the coil over 26v6a so ill keep a low power profile ,for now. i also checked the datashet of your mosfets and mine,i realised that your mosfets RDS(on) is around 0,5ohm but mine is around 1.6ohm,is this a major problem? if it’s really necessary i have a big heatsink,i could buy your U4 and 1 power mosfet(because i will power the coil with max 6A and the mosfet can resist to 10A,it will heat up). but i can’ buy more spare parts since it’s hard for me to make money :/ . just now i found that 1 mosfet was broken,its really interesting because they are just new out of the box and i only supplied the circuit once with 12v and 5v. looks like i found what was wrong but its the first time i’ve encountered something like this… i’ll replace today U4 (my equivalent)and R6 and see if i can resume my testing. thanks for your time and help 🙂 i’ll keep you updated with everything.

        • Looks like i fried my last 4452,have to wait till monday when a new package will arrive. i also bought 5 mosfets that are a little more powerful than the others STW11NK100Z. and i made a better pcb because the first one wasn’t for me. fetured with some switches to easly choose between a slayer circuit,and the curcuit with driver. i also have a switch for normal POT2 and audio J2 input so i can make test more easly and avoid touching something and damage my mosfet driver… ooh and i also bought a budget oscilloscope because the one that i had i think it was it’s broken.

  113. Hi! First of all, awesome work. My question is: Can you modulate the wave of a “plasma ball” as you did, by adding an OpAmp somewhere? I acquired one today and I would LOVE to have it playing some music. I supose I’ll have to analyze (somehow) the circuit. But, if it is possible, I will give it a try.


    • I think there are some of them out there that play music. But I’m sure it is doable. Just that with plasma inside a glass ball, not much sound comes out.

  114. How you can use just mains ac on primary that is basically a short circuit. How mosfet wont overheat or just blow up because mains can deliver high amount of current. Please tell me how to do that part because i want to make one 🙂 Nice work

    • I didn’t connect mains to my circuit. 32V maximum. But mains wouldn’t drive much current if you don’t let it to.

  115. Hi Mehdi,
    I need some clarifications on the power supplies. From what I got from the article the 12V supply is AC, while the 32V (VSUP) is DC. Am I right?
    Then if you could explain to me the reason for the requirements for second power supply (VSUP) it would be awesome: isn’t there already a large tension at the two ends of the primary coil with just the 12V supply? What’s the role in the VSUP in this?
    Thank you very much 😀 and keep up with the good work!

    • Hi,

      No both supplies are DC. The 12V is a lower current supply, which is meant to power the oscillator and low power circuit and also powering the gate driver IC. We don’t need a gate voltage above 12V on the transistors and in fact it can’t go over 20V or eh transistors will be damaged. But we like a larger DC voltage on the primary of the coil to increase the output power, the higher the voltage, the greater the arcs. Just that too much voltage there would also damage the transistors.

  116. Hi Mehdi,
    I’m going to build a tesla coil this summer with a NST (7 kV – 0.5 mA) to supply my primary, lots of capacitors, two screws as sparkle gap and stuffs. I’m not really handy with MOFSET but from what i read i think i can’t use your beautiful Dangerous speaker to control the output of my NST, Am i right? If i am wrong (i hope so) can i ask you some tips about which kind of transistor should i use?
    Thank you very much!

    • My circuit won’t work with NST. NSTs plug into mains (120VAC) and generate high output voltage. You can’t put that high voltage on my circuit either, it will blow up the transistors. You just need a high voltage capacitor on the NST output, and adjust your spark gap to make it arc at around 6kV to 7kV. The capacitor you choose, combined with the primary inductance, needs to oscillate at the resonance frequency of the coil secondary.

      Place an inductor much larger than the primary inductance to isolate the capacitor from the NST circuits when the arc happens so that the NST won’t effect the resonance at primary.

  117. hi my friend…
    One question for this schematic circuit. I have to ask for confirmation about the component that you called POT1. POT1 is a multi-turn trimmer. This components have 3 pins. One on left, one on the centre, and one on the right. Left and right pins, if you measure, you have a maximum resistor value, and it does not vary with the rotation of the trimmer. Instead left and centre pins or right and centre pins, the resistance value varies with the rotation of the trimmer.
    In your schematic, you connect just left and right pins, and the centre pin is non connect. So, if i connect in this situation, the resistance does not vary. Then central pin its necessary connect on the left pin or right pin of the trimmer.
    This is correct? Normally i connect in this way.
    But confirm me this situation ok?
    Thanks my Mehdi and

    greetings from Italy,

    • Hi Carmine,
      When I show the potentiometer like that in my schematic, I always mean center, with either right or left pins. This is to make a variable resistor. You can leave the unused side floating, or connect it to center like you mentioned.

        • Hi Mehdi…
          ok… i building your schematic, and the first schematic with out audio amplifier part, work well. I don’t have 32Vdc @10A… i have 28,6Vdc@5A. I do a test with bull lamp and a piece of wire… its incredibile… work well… but the second schematic with audio amplifier part, doesn’t work… i don’t no why… I think, but i don’t no, that the problem are the Vdc and Ampere… My voltage supply its very low… i connect my ipod and i listen very very very low the music… I tried to adjust frequency and PWM but nothing … what do you advise me to do ?

          thanks for your support…

          greetings from Italy,


          • Great! It works! (what’s a bull lamp?)

            What’s the size of your sparks or plasma coming out of your needle? Remeber for the loudest sound, you should have an all direction fluffy plasma running. If you have a single continuous arc, it will be pretty much silent. Increasing PWM to around 60% makes it largest.
            Do you have a scope? Can you see if your audio gets through and makes your PWM edge wiggle? Just to make sure the circuit is fine.
            Also increase the volume to see if that has any effect.

            • Hi Mehdi…
              Ok… today i try to power this circuit with my 2 Vcc power supply… Only one, can out this voltage: 28Vdc @ 5A. I have two of this Power Supply… so i connect both in serial for generate max 60 Vdc @ 5A.
              I power the circuit in 4 time:

              1 time: 30 Vcc @ 5A
              2 time: 40 Vcc @ 5A
              3 time: 50 Vcc @ 5A
              4 time: 60 Vcc @ 5A

              The spark was ver very long… i think like in your video… maybe 15/20mm… After many tests, i broken one of power supply… nothing of serious, just a diode 1N4007…

              After this situation, i think that the problem are the current… its very very low… I think that this circuit it must be piloted with max 7/8Ampere non more.
              because the mosfet 10 support maximum ampere for little second ones.
              When it powered with 50Vdc circuit , the voltage drop , once the circuit was switched to 19VDC !!! This is possible ? 31Vdc lost in voltage drop ? ! ? ! ? !
              This is my last test.
              What of do you think about this problem?


              ps: rebuild separately the audio circuit with all 40 volt and see what happens …

          • Not quite sure what’s going on with your last experiments. But high voltage supply creates larger VDS and that break you FETs. So be careful! To increase the spark length you can also increase your PWM somewhere around 60%.

  118. Hi! I want to make a tesla coil based on the most basic circuit possible. My first idea was to create sparks of thousands of volts and melt anything on my path using transformers of microwaves ovens to increase the input voltage bla bla… but the problem is that I live in Argentina, every single piece of electronics is so expensive that i can’t waste money trying to experiment with the circuit itself in order to find the best values. So I decided to start with the slayer exciter circuit, while I buy more powerful components, then modify it to feel the power of Thor. So what I need is some guidance to calculate every equation i have to use to create the primary-secondary coil, resonance, etc, a simple tiny list may be enough, or a detailed explanation of your coil. I learn and laugh a lot with your videos!

    • Hi Jerry,

      Go to website and there they provide detail information about Tesla Coil and its design. Good luck!

  119. I really like your projects Mehdi, I’m 14 and i have plans to build my Own music tesla coil! You’re really funny 😉 i have a few questions, what is a VSUP?, what kind of 12V supply can i use?

    • VSUP is a DC voltage supply close to 32V which I used. It should be able to provide 10A. You can raise it further too. the 12V supply is also a DC source at lower power

    • Hi!I’m a student from China.I’m very exciting to talking to you! I have some questions:A ground circuit diagram on your home, but the real figure on the wire without wire. Also, I see you have a lot of broken circuit on the map, I do not understand what is the meaning of. I have a wish, I would like to ask you to explain in detail the circuit with music. By the way, I would like to ask you to tell me your email address. Please!

  120. Hi Mehdi! I really enjoy your videos. I have always wondered if an ultraviolet laser could be used to ionize a channel in the air that would conduct electricity. Do you think aiming a UV laser through these high voltage arcs would respond to that sort of energy?

    I was thinking that if you ionized a channel in the air, you could transmit energy wirelessly with very high directivity. Since open air arcs produce ultraviolet light, it seems like thy could interfere constructively with the laser beam and make cause the current to flow through the laser really easily. Do you think that would work?

    Anyway, thanks for making these videos!

    • Hi Justin,

      I can’t tell the effect of the laser on the arcs until I try. But this sounds like a dangerous proposition. If the laser can ionize the air like that, a person crossing it will have a bad time!

  121. Hello Mehdi,

    Thanks for the article. Keep it up 🙂

    By the way on this line:
    “effect vital organs like brain or hurt and remains on the surface of body.”

    You meant heart*.

  122. Pingback: Tesla Coil Magic | Tiffany's Non-Blog

  123. You should play your ending beatbox music with the arcs, that would give the final touches to your eyebrow dance and it would awesome.

  124. click on my website link and you’ll see how you can use this kinda technics to make SUPERB fascinating pictures without the use of a camera,lens or filter !
    all films can be used : 6×6 or 24×36 or larger professional film.positive,negative,colourslides,infra-red or whatever material you can get your hands on.all working have to be done in absolute dark since you have to take all the films out of their cassette to expose them.the room/place should be ventilated since OZON is a byproduct and you should wear isolating footwear to avoid that a spark makes contact with earth by your toes or part of your foot.every serious email reaction is welcome :–))

    • I tend to make things from scratch to see how they really work. But thanks!
      Also the interrupted creates a digital saturated sound, not a clear music like the one I made. But I may use that scheme if I want a higher power coil.

      • There’s definitely something to be said for designing something from scratch! Full-spectrum audio coils (like yours) and DRSSTCs (big sparks, few notes) are different topologies, anyway, so our interrupter wouldn’t be useful for this coil. Try a oneTesla kit for your next project, it’s sure not to disappoint 😀

        You may enjoy this “shady” tinyTesla:

  125. I’d love to hook my coil up to some sort of sound input to modulate the arc. I cringed when you plugged your driver into the laptop. I don’t see any opto-couplers in your diagram. What are the chances of HV finding it’s way back into my laptop and killing it?

    • Depends on the power of your coil. If the arc is long and gets to your circuit, you are doomed! You could plug it to your cellphone that doesn’t have an earth connection. Just that the cellphone touchscreen wouldn’t work due to high radiation. You have to setup your cellphone and then start your coil.
      opto coupler is your safest bet of course!

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