Building the Poor-mans Mini Tesla Coil ( Slayer Exciter)

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Introduction: Building the Poor-mans Mini Tesla Coil ( Slayer Exciter)

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:

WIRELESSLY Light up:

  • 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

Destroy:

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

Create:

  • 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.

Step 2: Dangers

The output of the Slayer Exciter is high frequency high voltage. (I measured about 100KHz for those interested) Although the arcs are small, it's still able to catch things on fire and give you (admittedly very small) 3rd degree burns! These are safer than many other high voltage projects, and thus make a good starter projects along with static electricity and Van De Graaff generators. Just make sure to exercise caution when fiddling around with this circuit.

Also, Obviously, this thing is a fire hazard. I have managed to catch matches, pencils and wood, candles, and other flammable materials on fire. Without proper precautions, safety measures, and supervision, that can lead to an uncontrollable fires. If you plan on attempting that, do so far away from flammable furniture or housing, and materials and gasses.


Remember: I do NOT express any responsibility or liability of any kind, explicit, or implied. If you destroy your own stuff or someone else's stuff, do not come crying to me!

Step 3: Things You Will Need:

  • 700-800 feet of enameled magnet wire.
  • NPN transistor (if you plan to buy them, buy them in bulk. Likely, you will pop a few while working on the circuit. I recommend a high power transistor, they just work better.)
  • Here is a list of the transistors that should work. The one's I have used are italicized along with others who say that they work.
    • TIP3055 (works well @ 12V, just make sure to use a heat sink)
    • MJE3055T (works just as well as the TIP3055 does, and has proven to be the most reliable.)
    • 2N3055
    • TIP31C
    • TIP41
    • 2N3904(needs least two of them in parallel for reasonable output)
    • PN2222 (variant of 2N2222, just in a newer case, the TO-92)
    • 2N4401
    • unlabeled transistors from a camera flash circuit
    • many others. If you know of one that works well, post it in the comments!
  • clean PVC pipe to wind the coil around (I used a paper towel roll, but this is not ideal, especially in humid environments.)
  • PCB to solder everything to (or a breadboard for temporary builds) (I do not recommend sloppy builds, as this is high frequency AC stuff we are dealing with. So the sloppier the thing is built, and the longer the wires connecting things are, the more prone to failure it will be and the worse it will perform. Keep wires short, and take the time to build the circuit carefully and be neat when winding the L2 coil.)

Step 4: Tools Required:

  • Good soldering iron w/ solder and flux (if you plan on making this permanent)
  • variable power supply with current limiting options
  • L2 winding jig (Recomended)
  • Camera (optional)

Step 5: Optimal But Recommended:

  • Small signal diodes
  • many LED's of various colors and types
  • a few fluorescent bulbs (larger ones will glow brighter.)
  • christmas lights and other flashlight bulbs w/ several feet of wire
  • junk parts to fry
  • electronic equipment to drive nuts! (radios, calculators, remotes, and someone else's phone and computer)
  • candles and things to destroy!

Step 6: The All-important Schematic and How to Build It. (small TO92 Version)

There is not much to this circuit. Above are all the graphics and pictures. After you gather all your materials, take your transistor and wire it up. (Note, these instructions ONLY apply to the schematics shown below. NOT the video version of the circuit using a MJE3055T.)

1) Connect the emitter of the transistor to the common or ground.

2) Connect the base of your transistor to one end of the resistor, as well as to the bottom of the L2 coil. (this creates the differentiated negative feedback, which allows the transistor to oscillate.)

3) This is a little tricky. I have made a graphic to illustrate this step visually. If the winding's of your L1 coil run around the L2 coil in the same direction, (where both winding's run either clockwise or counter-clockwise), then the end closer to the top connects to collector. If the winding's go against each other, (One goes around counter-clockwise while the other is clockwise and Vise-Versa) then the bottom end connects to the collector of the transistor. If you have this incorrect, you may damage your transistor. If you are not sure when about to apply power, use current limiting, or a low enough voltage.

4) Connect the other end of L1 to the positive rail.

5) (Optional) Connect the negative end of the LED's to the base. (They are wired in series, so test them to make sure both light up when connected to a 6V power supply w/ current limiting resistor.) The side with the flat ridges or longer terminals if they are brand new LEDs should face the transistor such that the terminal nearest the flat ridge is connected to the base

6) Now attach the capacitor between the positive and negative rail. I found the best type is a high value film or ceramic cap, or the largest electrolytic capacitor you can source. Now the circuit is done, click the next step for testing and troubleshooting.

Step 7: Testing and Troubleshooting (TO-92 Small Slayer Exciter)

Here is the troubleshooting guide for the first variant of the circuit I built, it is for the versions using a 2N2222, 3904, 4401, etc:

  • It may be tempting to connect your circuit directly to a 9V power supply or battery, but this is a bad choice. That's how I burned out most of my transistors during my experimentation. After you have built your circuit check over everything and make sure it is wired correctly, and if it was done on a PCB, make sure there are no solder bridges.
  • First, after paying close attention to the polarity, power the project with 4.5V-5V, or 3 AA batteries to the rails and see if the leds light up, or if you can get a neon lamp to glow next to the output L2 coil. Keep a close eye on the transistors, and make sure they stay cool to the touch. If they are becoming really hot, with no neon bulbs glowing, then you have a problem. If it all checks out, increase the power. At 6-7.5V (or about 4-5 AA batteries in series), I found that the circuit can can output enough radiant energy to make a fluorescent light glow. Adjust the number of winding's for the best performance. I found 9 turns on less than 9V works best. Now, power the exciter with 9 volts, from a power supply or 6 AA batteries in series. (avoid using a 9V battery for this circuit, especially a heavy duty garbage battery!!!! They will die quickly and have a really high ESR). If it seems to work, hold it on for a few seconds. Keep your fingers on both the kill switch and the transistors. Make sure they do not get hot.

**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:

  • 90% of the time, this means that either:
    • A) The value of the bias resistor is too low, (try a higher value resistor, maybe 4.7k-20k)
    • B) The polarity of the L1 coil may be incorrect. (try switching the polarity)
    • C) The number of windings is way too low, it should be more than 3 at least.

IF the transistor is COOL to the touch, and does not work well or at all judging by the neon lamp test:

  • The polarity of the L1 coil incorrect. (try switching the polarity)
  • The bias resistor is too high a value. (try less than 1 MEGohm.)
  • You have incorrectly built the circuit, (check and recheck the wiring)
  • Too many turns for the L1 coil causes poor performance (try less windings for the primary)
  • You screwed the pooch and killed your transistor

IF the circuit works, and the transistor is getting warm, borderline hot, but still does not function as well as mine:

  • Adjust the number of turns on the primary, or L1. I find 9 turns work will for less than 9V operation.
  • Adjust the bias resistor value, if it is too low, the transistor gets excessively hot. Too high, the circuit does not work well.
  • Notice that the version shown in the video uses a larger transistor, not the small TO-92 ones:
    • You have the cravings for LOTS of radiation, so try a BIGGER and BETTER transistor!!!!!
  • Using transistors of higher current gain and power dissipation will be better.

Step 8: Testing and Troubleshooting (Larger TO-220 Version Shown in Video)

Here is the troubleshooting guide for the version of the slayer exciter shown in the video this guide is for the more powerful 3055, TIP31C, TIP41, etc.

  • After building the circuit and realising it does not work, first, make sure you power supply can deliver 12V at 1.5A minimum for best performance. I found that the circuit will draw as much as 3A at 20V, so if you plan on using such high voltages, make sure the supply can deliver the current.
  • It may be tempting to connect your circuit directly to a 12V 1A power supply or SLA battery right away, but this is a bad idea. After you have built your circuit check over everything and make sure it is wired correctly, and if it was done on a PCB, make sure there are no solder bridges. First, after paying close attention to the polarity, power the project with 6V, or 4 AA batteries to the rails and do the neon lamp test. Keep a close eye on the transistors, and make sure they stay cool to the touch. If they are becoming really hot, with no neon bulbs glowing, then you have a problem, and you may need to add a really big heatsink. If it all checks out, increase the voltage to 12V with a lamp in series with the power supply if it is not current limited to 2A. (as is the case if you use a SLA battery). It should still work, but perhaps poorly. Adjust the number of winding's and the bias resistor for best performance. I found 3-5 turns for 12V works best. (For this variant, DO NOT EVER EVER use a 9V battery, especially a heavy duty garbage battery!!!! They will die quickly, do not store much energy, have really poor power density, cannot deliver more than an amp, and they are just really bad. I would not be surprised if the battery leaks or explodes after using it for this circuit.). If it seems to work, hold it on for a few seconds. Keep your fingers on both the kill switch and the transistors. Make sure they do not get hot.

----------------------------------------------------------------------------------------

**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:

  • This 90% of the time means that either:
    • A) The value of the bias resistor is too low, (try a higher value resistor)
    • B) The polarity of the L1 coil may be incorrect. (try switching the polarity)
  • IF the transistor is COOL to the touch, and does not work will or at all judging by the neon lamp test:
    • The polarity of the L1 coil incorrect. (try switching the polarity)
    • The bias resistor is too high a value. (try less than 10k.)
    • You have incorrectly built the circuit, (check and recheck the wiring)
    • Too many turns for the L1 coil causes poor performance (try less windings for the primary)
    • You screwed the pooch and killed your transistor
  • IF the circuit works, and the transistor is getting warm, borderline hot, but still does not function as well as mine:
    • Adjust the number of turns on the primary, or L1. I find 3-5 turns work will for 12V operation.
    • Adjust the bias resistor value, if it is too low, the transistor gets excessively hot. Too high, the circuit does not work well.
    • 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.
    • You have the cravings for LOTS more radiation and EMI, try build a proper tesla coil! That is the next logical step up! :).

Step 9: All My Pictures

11 People Made This Project!

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3 Questions

0

we are glowing tube lights using that tesla coil, instead of the tube light what if we use a small LED bulb?

will the LED bulb get destroyed?

0

Did you watch the tutorial video? I already demonstrated LED's lighting!

LED's work best with low current DC at a couple volts with a high impedance supply. Because they only need a few milliamps, you can simply use an antenna and induce a high frequency current in it from/to ground. By means of a rectification with additional diodes, the DC current can power an LED.

5 more answers

0

I did everything, what u have done in your video but still, my Tesla is not working

0

Then you have did something wrong. Please refer to the troubleshooting guide in the instructable.

0

sir, san i get ur personal email ID, i can talk to u easily?

0

No, sorry. Just leave a descriptive comment of the issue. Simply asking for help without providing any information about the build is useless.

0

ok i will

I'm wondering if a IRFP250 transistor would work for this project? I have no experience in electronics and my electronic shop doesn't have a lot to offer (other model includes 2SD2489, 2SA1943 and 2SB630). I think that I have the rest of the material and should be good to try.
thanks

0

Yes but only with modifications. Look at my simple SSTC project for my take on a MOSFET based slayer exciter.

Also you may want to learn more about basic electronic theory or building the simple slayer exciter before diving in. Just sayin because otherwise your chances of sucess are smaller than being struck by lighting.

what if i use a small LED bulb instead of a tube light

0

For what purpose?

566 Comments

It's not working for me . I have been working on this for past 1 month.
Help me bro. I wound 750-800 turns of secondary coil of 28 gauge size, and for primary I used some 15-18 gauge wire of 7-8 turns .and also use two 10 mf capacitor in parallel. For power source since I don't have 12 v battery I made one 9 v battery and two 1.5 v AA battery. I used mje3055t transistor. Even my led in circuit is not working. What should I do now .I have very few days for my project completion so pls do me this favour

DSC_0417-3.jpg
1 reply

This circuit is very fiddly, as all of the other people in the comments have had identical issues. I find that the ones on the deadline for some science project with minimal background knowledge in electronics typically fail to get this circuit to function.

As a general answer to general requests for help, I point users to the last page of the instructable for troubleshooting, since I assume (given you made no mention of your method to troubleshooting) you did not follow those instructions. Let me know what your results are from attempting each of the steps in the troubleshooting guide, then I might be able to help.

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20mF capacitor is huge. I assume you mean μF. It would be more ideal to use film or MLCC capacitors with better ESR/LSR characteristics in parallel with those electrolytic caps. That high capacitance from those is good for low frequency (60Hz) filtering but useless at filtering higher frequencies this circuit requires.

As I mentioned in the troubleshooting guide, a 9V battery will not provide enough current to give good results. 2 standard cells do not provide enough voltage for good results. They will work but expect very poor performance. If you have an old router or toy or something that uses a old-fashioned 9V or 12V wall adaptor capable of a 600mA minimum, then you can use that. However it has to be the heavy blocky type. Modern small / light ones have regulated outputs that shut down when they detect overcurrent. You will still get better performance from a proper lab bench power supply where you can adjust the voltage and current limits freely and independently.

why do i have to use resistors on my led lights for them to light up w my 9 volt slayer exciter ? i thought they would just light up in my hand? or do i need to change something about the way its constructed?

1510815366797-1206357080.jpg

hello...i have more than 1500 turns of 30 gauge enameled copper wire wound over 22" long pvc pipe of 2.5" diameter.....will the circuit shown in the video work for this....pls its urgent

Hi everyone! I've made my tesla coil. It has about 1330 turns of 0,2mm enameled wire in one coil and 9 turns of about 1,2mm diameter wire in the second. I used 1MOhm resistor , 2N2222 transistor and powered it with 9V battery. I checked with multimeter ( and with my fingers ) that high voltage is produced in the coil, but it can't light the neon light wireless. It can light the LED but only if it touch the wire of coil. I tried to change number of turns in smaller coil and to change the resistor to smaller but still nothing. Anyone have any ideawhy isn't it working? I need it to a school project.

Thank you Max, here's another version of the circuit with 6v instead of 9, and I've tried adding the 22k resistor instead of the 5.1k that comes with the kit, and tried reversing polarities...still nothing

IMG_20170511_085644.jpg
1 reply

Snap circuits are not ideal for this type of circuit. We are in the realm of high frequency RF applications. Every inch of wiring has non-negligible parasitic properties like capacitance and inductance and can act like an antenna, picking up random crap and screwing with the operation of the circuit. This circuit in particular actually takes advantage of that to work! But you should build this circuit on a PCB or a breadboard.

Also this circuit is very good at killing transistors when it is not oscillating properly because of the low-resistance path between emitter and collector. If the circuit does work then the transistor is turning on and off millions of times per second and the inducance of the primary ensures reasonable power losses in the transistor. But if it stops oscillating, then the transistor (biased on) will conduct large DC current and overheat, and pontenially die. I would not be suprised if your transistor block is dead. You can check with a multimeter and measure the Vdrop of the PN junctions between emitter and base and collector and base to see if you get the 0.5V to 0.7V reading one would expect from standard PN junctions.

Can someone please help, I've tried for many hours to make a slayer exciter and can't get it to work. I've tried different transistors (nte123a is supposedly equivalent to 2n2222a?), I've switched the primary coil back and forth many times, the primary copper coil has been wrapped both 3 times and 4 times and had a coating which I removed but none of this has worked, the secondary coil was taken from inside an automotive relay. Very frustrating.

slayer.jpg
1 reply

These circuits are very frustrating indeed! Have you referred to my the last troubleshooting step? I see a few problems already but I'll let you discover them! ;)

I made it and it worked with a 12 v battery .But the coil broke the battery because it used up more than 20 amps at a time .Any ideas about what i did wrong , or what i can do to power it with any other way ?

3 replies

I need more details to help. Did you read the troubleshooting guide at the end?

i have used 26 gauge copper wire and coiled it completely on pvc pipe of 150mm length and 28mm diameter 300 turns . which resistor and transistor i should use to make mini teslacoil with 9V DC battery PLZ reply immidiately

i have used 26 gauge copper wire and coiled it completely on pvc pipe of 150mm length and 28mm diameter. which resistor and transistor i should use to make mini teslacoil with 9V DC battery

it will work with 10 to 15 cm length