A slayer exciter is basically a small solid state tesla coil, usually a one transistor design. The circuitry for it is simple. One of the first things anyone who has built a joule thief will notice, is that the circuitry is very similar. The biggest difference is that the small transformer or inductor has been replaced with a primary/secondary tesla coil configuration, and that the feedback is capacitively coupled. (There is a good abount of capacitance between the 'top' of the coil, and ground.)

There are many awesome thing these exciters can do!
they can:


  • neon lights!-----------------------------------------(several feet away)
  • florescent tubes!----------------------------------(within about a foot)
  • CFL's!-----------------------------------------------(within about a foot)
  • EL wire---------------(it does not work well for me. If anyone tries it, please tell me your results!)
  • LED's!-----------------------------------------------(across the room if done right)
  • and even small incandescent lights! -------(with an L3 coil)
  • paper with pencil markings -------------------(before it catches fire!)

Burn and ignite:

  • candles
  • wood (pencils)
  • human flesh (now my fingers smell burnt)
  • paper


  • crappy / half dead LED's
  • bacteria
  • sensitive electronic equipment (phones, computers, SD cards, CD's, blu rays, flash drives)
  • someone else's stuff


  • ion wind motors
  • the coolest lantern or light on earth
  • fires
  • plasma cutter

►Make following electronic equipment go crazy:

  • calculators
  • watches
  • digital clocks and alarms
  • devices with capacitive touchscreens (PlayStation VIVA, smartphones, feature phones, tablets)
  • UHF remotes

Transmit wacky sounds (loads of EMI) to:

  • AM radio
  • FM radio
  • shortwave radio
  • HAM radios possibly
  • TV interference

Here is how to make a my version of the more powerful exciter (These videos were made awhile after this intructable, so the only issue with it is thermal management.) Please do not get the instructions in this video confused with the instructions for the later TO-92 one in the further steps. Different bias resistor values should be used for either of these 2 versons.

Step 1: A rundown of my experimentation

I did modify the circuit a LOT before I was happy with the results. Sadly, I did not take pictures of my circuit on the breadboard.

  • The first picture show first circuit. I could not get to work.
  • The second picture shows my first working design. I chewed through many transistors, and it was not very stable, but it worked.
  • In hopes for better performance and reliably, I tried a darlington pair. It put out about the same amount of power, but did not kill my transistors. I believe this is because it increased the gain and the feedback from L2 was enough to sustain the oscillation. I think this is because it did not latch up and pop my transistors.
  • I realized after running the circuit for awhile that I wired it wrong on my breadboard but it worked anyway. I decided to "fix" it, and ended up burning out my last 4401. From then on I had to resort to 2n3904's. This darlington pair test was inconclusive due to my mistake of not having the collector from the first transistor connected to anything. I learned that if it ain't broke, don't fix it :P
  • I finally decided to revert to my original circuit, except this time with all 3 remaining 2N3904's all in parallel. (collector to collector, base to base, emitter to emitter.) This worked exceptionally well, and I haven't killed any transistors since then! Now, I even get plasma shooting out the end! If you decide to build this, use that configuration, but use more powerful transistors, like 2N2222's or 2N4401's. They can handle more current.
  • [UPDATE, March 2014] Later on I then decided to use a MJE3055 transistor instead of the weak TO92 transistors, and started to get much better performance. I upped the voltage from 9V to 12V, and replaced the 1Mohm resistor for a 10K resistor. You can get the instructional details in the video.
  • [UPDATE May, 2015] I have now began work on a MOSFET version of the slayer exciter, and with 50V and a computer heatsink, I can achieve results that border a small SSTC!!! (Solid State Tesla Coil) Unfortunately the complexity of the circuit did increase, due to the need to drive the gate of the FET with buffer to allow fast switching. Luckily it is ultra stable when tuned correctly, and can deliver much more power with more supply voltage. I increased the size of the heatsink compared to what I used in the first slayer exciter video, and have active cooling fan giving some airflow. Now I can let it run indefinitely at 24V and beyond! :D Note: The topload is still critical, if it is too large, performance will decrease. Also I can draw up to 3 inch long, incredibly hot arcs, and get corona that is about an inch long!!! I have even managed to "burn out" a screwdriver from the inside-out! Where the shaft is encapsulated in clear plastic, the plastic began to experience dielectric breakdown and began to melt, and eventually the electricity burned a carbonized hole all the way through the plastic to my fingers, Ouch! The electricity must really love me! :P.
Can u send me the pic of circuit in fb<br>#Riyaan Jamaludhin
Can u make a video on the circuit of this model because i cannot understand the circuit or can u please explain how to do the circuit bcz i hav to submit my project next week .... <br>i dont know where to fix the capacitor and those all stuff in circuit board olease look into it and make a video or explain
I already made 2 videos for this circuit, the first one shows the schematic and the second shows off the capabilities of it. They are in the instructable on the 1st step.
What happens if my secondary coil overlaps at certain places
Your coil would look sloppy. But too much overlapping could increase the parasitic capacitance of the secondary coil, lowering its overall resonant frequency, causing the already very weak coupling between the primary and secondary to suffer because the circuit will only be in tune (to achieve maximum voltage swings) at a lower frequency, causing the overall output to be very very slightly lower.<br><br>If you wind multiple layers on top on one another, the parasitic capacitance will almost certainly be too high, and you would exceed the dielectric breakdown of the enamel insulation on the coils before achieving any reasonable output at all, which in turn will basicly short out the secondary after the enamel carbonizes.
hey can u please tell me what at the exact values of your capacitors and please reply fast as I have to represent my school for state science exhibition in 13 DEC pls reply fast (the mje3055t circuit)
<p>So many people ask frantically about this circuit for science projects, though from my experience trying to help them, they end up not making it work in time. With only a couple days, I would look into doing something simpler if you are not familiar with electronics. It took me about a month to get this circuit to work as well as it does in the video.</p><p>This circuit is quite experimental, and VERY temperamental. I am NOT kidding, I had a friend who came to visit, and I wanted to build this circuit quickly while he was here, and after about 4 hours of trying to get it to just work, I could not and it was time for him to leave. Even the tiniest differences between my build and your build (such as the diameter of the coil, the length, number of turns, surroundings, topload, and components used) can have a huge roll on what parts are best to use.</p><p>==================================================</p><p><strong>REGARDLESS, I will try to help you. </strong></p><p>To see what parts I used, please refer to my video posted on this instructable and find the schematic where it shows the parts. For decoupling capacitors (ones that go directly across the power supply) should be connected as close to the rest of the circuit as possible (keep lead lengths short) and keep all the connections between the circuit as short as possible. The decoupling capacitor should be low ESR, and high capacitance. In layman's terms, a BIGASS capacitor. Maybe 100uF or more. generally, more = better 1000uF or more is probably overkill though.</p><p>If you build the circuit up and it does not work, first refer to my comprehensive troubleshooting guide. I have LOADs of great info to make it easy to get the circuit up and running, and if you are willing to put in the time, optimize it and get it working great.</p>
how much Ampere does this circuit requires
<p>I measured it for my circuit at 5:19 in my second video (cool things you can do...) at 24V. However I should have been monitoring the voltage as well as the current because I suspect my 2A power supply was dropping out a little, leading to possibly as low as 18V. For my power supply, I was using a unregulated 4A 12V linear power supply (15V open circuit) and a regulated lm317 based power supply set to 12V. Avoid connecting multiple power supplies in series or parelell as this is bad practice unless you know what you are doing.</p>
<p>thnks max with yr help I won the regional exhibition and is going for nationals..... Thanks</p>
max I just wanted to get the info for ur capacitor or u suggest me any high volt. cap. that I can use as the shop Keeper doesn't allow anyone to buy a capacitor without any unit so pls help me and my circuit is working good but I want more power. currently I am using 3 electrolytic caps (2-63v and other I don't remember) and other a disc capacitor. pls reply fast and my exhibition is from 16 DEC:) thanks.....
<p>You're welcome. Most any decoupling capacitor value is fine. If you look at my video, you might notice in some areas, I have a large electrolytic green capacitor that's 1000uF, and another portion where I have effectively 300nF of capacitance with 3 104K capacitors in parallel Both worked equally as well.</p><p>To get more performance, again, refer to the troubleshooting step, it will help you optimize the circuit. I would be just repeating what is written there otherwise.</p><p>You need to experiment with the number of turns on the primary, experiment with the exact pullup resistor value considering the voltage you plan to use and the strength of the capacitive coupling between the secondary and primary (this depends on a million things, mostly how your circuit is built physically) and make sure you have an adequate power supply. One that can deliver at least 9V, and several amps. small batteries are NOT suitable, small wallwart transformers might NOT be suitable.</p>
I will be using these..OK..<br>
<p>Hopefully you have enough MJE3055's on hand, because tomorrow is saturday, radioshack is not going to be open, and buying parts online is out of the question with only one full day left before you present your project. I have burned out quite a few, and that can cause you to waste troubleshooting time. So build a simple &quot;jig&quot; to test your transistor. A simple trasistor switch controlling a lamp should suffice.</p>
Thank you max. <br>
<p>,I have used a 24 Awg wire . will my coil work?????</p>
Probably.30 awg is ideal<br>
<p>ok this time I've copied your plan to the letter with exception to the capacitors. As I can't find them in the city.</p><p>Still no luck.</p><p>Checking the battery voltage when connecting the system sees a 1volt drop</p>
<p>What battery are you using? In my video shown in the instructable, I used a regulated 12V power supply that is capable of delivering 2A peek for a short duration, and 1.5A continuous.</p><p>So I assume you used a brand new MJE3055?</p>
<p>I bought a TIP41C transistor</p><p>I screwed a piece of metal to the back of it to act as a heat sinc</p><p>If the pinset on the TIP41C is the same as in your video, then they're setup the same.</p><p>I'm using a 9Volt rectangular battery.</p>
<p>Just tried connecting my 12Volt car battery.</p><p>Same. nothing happened.</p>
<p>On the power site of my 22k resistor, I have 12V, on the other side of the resistor I only have 0.5V</p><p>Is this correct? Doesn't sound right to me.</p>
<p>That sounds perfect, the NPN transistor you have will act like a open circuit until you get to around 0.4-0.6V, where it will then start conducting electricity. It is like the minimum pressure you need on a check value to make it flow water the right way. Same for electronics.</p><p>Try a 1K resistor if the transistor is not getting warm. And also place a car flashing lamp or maybe a car head lamp in series with the 12V car battery to keep the current low in case of a short circuit or something. A car battery can deliver over 500A, which, if something is wrong, then the transistor will probably explode. Also, did you put any thermal paste on the heatsink? Radioshack will again have some of that if you need it, or online stores like Amazon.</p>
<p>ok I changed to a 1k resister.</p><p>I also checked every joint with an Ohm meter :) found a few try ones and fixed them.</p><p>This time when I connected the power, I got a spark when connecting.</p><p>The transistor started to heat up. But still no action on the light bulb :(</p>
<p>Oh, got my hands on a Capacitor too. but its only 100pF</p><p>Added this. after looking at a chart, seems like it's pretty small.</p>
Sounds great! Just follow the last half of step 8 for improving performance and you should be set! Try a few large electrolytic capacitors connected to where power connected as close physicly to the circuit.( as close to the L1 coil and emitter as possible. Keep the wiring as short as possible.)
<p>steps? which part is step 8? it's not like they're labelled :)</p>
<p><strong>**Failure modes of operation, and how to fix them:** IF the transistor gets HOT, and it does not work well or at all judging by the neon lamp test:</strong></p><ul> <br><li><strong>This 90% of the time means that either:</strong> <br><ul> <br><li>A) The value of the bias resistor is too low, (try a higher value resistor)<li>B) The polarity of the L1 coil may be incorrect. (try switching the polarity)</ul></ul><ul> <br><li><strong>IF the transistor is COOL to the touch, and does not work will or at all judging by the neon lamp test:</strong> <br><ul> <br><li>The polarity of the L1 coil incorrect. (try switching the polarity)<li>The bias resistor is too high a value. (try less than 10k.)<li>You have incorrectly built the circuit, (check and recheck the wiring)<li>Too many turns for the L1 coil causes poor performance (try less windings for the primary)<li>You screwed the pooch and killed your transistor</ul></ul><ul> <br><li>IF the circuit works, and the transistor is getting warm, borderline hot, but still does not function as well as mine: <br><ul> <br><li>Adjust the number of turns on the primary, or L1. I find 3-5 turns work will for 12V operation.<li>Adjust the bias resistor value, if it is too low, the transistor gets excessively hot. Too high, the circuit does not work well.<li>Try a different transistor, or one from a reputable brand, like Linear Technology, STmicroelectronics, Texas Instruments, ON semiconductor, or the ones you find on Jameco, radioshack (now bankrupt :( ) Digi Key, mouser, etc. Avoid the too-good-to-be-true deals on eBay. Often you will get hung-wan-low quality garbage, or old used and recycled transistors that have been cleaned up and the old part number of an inferior transistor scrubbed off and a new one printed on. Obviously you do not want that garbage.<li>You have the cravings for LOTS more radiation and EMI, try build a proper tesla coil! That is the next logical step up! :).</ul></ul>
<p>I just started on my circuit i have failed at the 2 gos so far but its not your circuit but another similar ....i was thinking perhaps it might be a good idea to have the resistor to be a pot instead since every one seems to want to try other transistors ..Never tried some thing like this before i tended to always use a fly back transformer but this is more interesting since your making the coil.I am reading all the problems some people are having and i am glad it is not easy to make one of these you need to be patient and learn from mistakes never learn a thing it it works ; {</p>
<p>ok, so I'm off to buy a little neon lamp.</p><p>I have been using a fluro house light bulb and a torch that uses those little diode bulbs, but there was no result with them.</p><p>My Primary currently has 2 winds. Will try adding a wind.</p><p>I however, would not have thought there would be any effect given that it's insulated wiring you're using (and me).</p><p>I was using the 9Volt battery earlier as you recall. Last night when I fired it up, I was using that battery connector and just wired the car battery through it's contacts. The connector wire to the circuit board instantly caught fire and fried :) so at least now I know I've got a circuit.</p><p>I guess I better buy and hook up a car light bulb too right after the batter positive pole, as you advised.</p>
<p>ONE LAST THING: If you ever suspect your transistor has been cooked, but are not sure, you can always google how to test NPN transistors. My favorite way to do this is to wire up a NPN transistor is in the &quot;common emitter configuration&quot; so as to use it as an electrical switch, and see if I can turn on and off LEDs or small lamps with it by applying a small current to the base by connecting the base, through that 1K resistor, to Vcc, the +12V. </p>
<p>I have two transistors, I did this test on both. They both show 1 when testing ANY combination of legs of the transistor.</p>
<p>Post some photo's and pictures, even videos of your current build, so I can look over your wiring and what parts you have chosen. I can really help you much more if you do that, rather than teaching you all the electronics knowledge and how to test stuff yourself through long, boring comments. After all, a picture is worth 1000 words, and a video is 30 pictures per second, or equivalently, 3000 pictures per second! :)</p>
<p>I added some images but they've dissapeared.</p><p>Adding them again.</p>
<p><strong>* </strong>You <strong>will</strong> <em>ABSOLUTELY</em> need a large heatsink, unless running on a 9V battery or less and getting hopeless performance.</p><p>~~~~~~</p><p><strong>*</strong> It seems like the wiring is correct, assuming the leftmost blue wire is the negative of the battery, and the wire closest to the matchstick is the positive, or maybe the bulb you have in series. HOWEVER, have you verified that the polarity of the secondary coil is correct? I always get this wrong when I build the circuit, even if I pay attention to the wiring!</p><p>~~~~~~</p><p><strong>* </strong>The only thing I would change is the capacitor for a larger electrolytic capacitor, or some beefy ceramic or film caps. The capacitance should be higher than 1uF, preferably higher than 10uF. Thats why I had so many capacitors in series with the supply.</p><p>~~~~~~</p><p><strong>One last tip: </strong>Try soldering a small wire that easily goes into the breadboard to the copper stranded wires, or cut away half the strands and solder them together so that instead of attempting to shove those PITA wires into place, and risk them shorting out with other stuff, they just insert easily.</p><p><strong>BTW,</strong> when you mentioned there was a spark coming from it, did you mean like when the power was connected, that you got some yellow sparks (like grinding metal sparks, or sparklers) or did you mean a thin blue arc out of the top of the coil? (like the high voltage discharge from the top of the coil?)</p>
<p>well I have a little plate there at the moment to act as a heat sink. I'm only connecting it for a few seconds at a time right now while I measure with the meter. I'm getting .7v on the other side of the resister. Should be enough to fire off the transistor.</p><p>I'm getting 12V to the transister center pole.</p><p>I've tried swapping over the wires for the external coil too. No change.</p><p>Currently, the transistor isn't generating any heat at all.</p><p>Makes me think it's dead.</p>
<p><iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/F1A5DBmTKlY" width="500"></iframe></p><p>You can use the circuit here to test the transistor. However, the larger transistors need more current to turn on, and so instead of the base going to a finger to act like that pull up resistor in this circuit, you should connect the base to that 1K resistor, and have that go the the positive of the battery. Ans instead of an LED, use a small lamp (one rated the same voltage as your battery) and no 1K resistor that is in the video. (thats to prevent killing the LED.)</p>
<p>WOW, talk about overkill for testing a 50 cent transistor.</p><p>I think I'll wait till Monday then get a new TIP41C :)</p>
<p>lol thats fine too. I am impatient and want to verify if it is still working, so that if it is good, I do not lose time. :) It only take a minute to breadboard up a simple tester!</p>
<p>ok, a simple ohm meter test shows me that the second transistor, the new one that I bought, is dead before I even used it. Back to the shop again :(</p>
<p>I highly doubt that the transistor would be dead out fresh out of the packaging. Especially as rugged as they are. If you use an ohmmeter to test transistors, you really need to know what you are doing, and it helps to understand some basics of the transistor. <em>(Compare this to when you first even looked under the hood of a car, without understanding much of anything, and spent a long time attempting to fix an issue maybe on your own without the help of someone more experienced, possibly making it worse. Surely this is happened to you at least once?)</em></p><p>~~~~</p><p> Watch this video about how to test the transistor with a ohm meter, or I recommend just building the circuit I described earlier. This method is tedious, and not particularly easy, but if you really want to use your ohm meter, make sure to measure it correctly. </p><p><iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/qM7_h8my8eA" width="500"></iframe></p>
<p>ok, now I've got two good transistors.</p><p>but they aren't getting hot.</p>
<p>Well they shouldn't get hot if you have the heatsink, with thermal paste. (that is necessary stuff. The heatsink is pointless if you cannot get the heat from the transistor to it.) That said, Do you have a picture of the entire setup, including the bulb? <strong>I suspect the bulb you have in series is too small a wattage, in which case it is absorbing all the energy, and dropping away all the voltage, leaving hardly any voltage for the exciter.</strong> The voltage across the slayer should be around 11-12V. If it is, then the bulb is probably dim because it is only dropping 1 or so volt, and very little current is flowing, in which case, a smaller value resistor is needed. (though it is already really low, I can not imagine why it would need to be lower.)</p>
<p>This is so frustrating.</p><p>This whole thing should have taken me an hour to do. no more.</p><p>so far, over a week.</p><p>I swear I used to get .7-.9V on the other site of the resistor. Now I'm getting the full battery voltage. I have tried all my resistors, and the same, I ever removed the transistor.</p><p>What the heck would cause that?</p><p>I even changed to the 9V battery with no globe. getting 9v on both sides of the resistors. ?????</p>
<p><em>I know how you feel, I spent over a MONTH when I first attempted to make the damned circuit work, and I did not succeed at first. It was when tried again with a much better understanding of electronics, it again took over a month of tinkering, but I was able to get it working, and eventually I achieved really good performance and made the video. Many people go out thinking this is going to be a easy project for a science fair, I have had countless comments posted asking desperately for help mentioning they need it working for a fair in less than a week. </em></p><p><em><br></em></p><p><em>Part of the reason I had such difficulty was the version of the schematic I used, and also I didn't understand how it worked, or the physics behind it. For instance: How does that feedback wire from the secondary coil cause the transistor to turn on and off at the right times??? After all, electronics 101 says that a circuit has to be a complete closed loop, and the other end of the L2 coil is just free standing!!! It makes no sense!!!</em></p><p>~~~~~~~~</p><p>Anyway, it sounds like a broken connection. Breadboards are notoriously unreliable, wires pop out, etc. Did you scrape off the enamel coating on the wires, and maybe the oxidation on the resistor if it is an old resistor? Check the ground connections in the circuit, and make sure that the emitter connected to ground. Is it possible the TIP42C transistor you have in actually not that, but a different part number, possibly a MOSFET? 0.7V is about right.</p><p>Build up that simple transistor tester circuit below, so that way you can always be sure they still work. With the switch turned on, the ;lamp should come on. Make sure to use the one rated for 9V, or if your battery is half dead, then you can use a 6V lantern lamp. LEDs will work too if you make sure the polarity is right and there is a &gt;220 ohm resistor in series with it. (I just make that circuit in paint really quickly, I tried to make it as visuall as possible.)</p>
<p>That resistor is a 1K resistor, although it appears to be brouwn black orange, which is 10K. do not use a 10K resistor, it should be around roughly 1K</p>
<p>I'm getting lost.</p><p>I set a 1k resister between the + and -</p><p>I still get 9v even after the resister.</p><p>Shouldn't the resister be dropping the voltage to .7v ?</p>
<p>If the voltage across where you connect power to the circuit (emitter, and free end of the coil) is less than 6V, then it is too low.</p>
<p>You are just going to need to learn about the basics of ohms law and watts law for me to answer that question in a way you will understand.</p><p><a href="https://www.youtube.com/user/powermaks/playlists" rel="nofollow">https://www.youtube.com/user/powermaks/playlists</a></p><p><iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/1bKkXt6PCXw" width="500"></iframe></p><p>First, you need to understand that voltage is a measure between 2 points. If you just give me a random number, like &quot;0.7V,&quot; I assume this means between whatever node you are referring to and the ground, or negative of the battery (this reference point is called the &quot;common.&quot;). If you place the 1K resistor directly across the resistor, it will drop 9V across it, and since it is a 1K resistor, it will have 9mA of current go through it. The larger the resistance is, the less current will flow for a given voltage. This is a very useful way to limit the current, so that we can precisely control the current bias of the base of the transistor, to get it to just barely turn on.</p><p>The transistor base is like a diode. When it is forward biased, and you are pushing some small amount of current through it, a few mA's, then the voltage between that base of the transistor and ground will be approximately 0.7V. This will hold loosely true over a large range of currents. Look at this graph to see what I am referring to:</p><p><a href="http://people.seas.harvard.edu/~jones/es154/lectures/lecture_2/diode_characteristics/iv_charac_3.jpg" rel="nofollow">http://people.seas.harvard.edu/~jones/es154/lectur...</a></p><p>If you try and force the voltage between the base and emitter to be considerably higher than 0.7V, WAYY too much current will flow, and you will kill your transistor. Whats what we need the reisstor to do. We need to limit the current, and that is done by dropping the voltage. </p>

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