Slayer Exciter Circuit (Poor Man's Tesla Coil)




Introduction: Slayer Exciter Circuit (Poor Man's Tesla Coil)

About: I love making and breaking electronics.

Hello everyone!! Today I am going to show you how to make a Slayer Exciter Circuit, which works almost like a Tesla Coil. So what is a Slayer Exciter? It is a self-tuning and self-resonating Tesla Coil. Tesla Coil is an electrical Resonant Transformer Circuit that basically produces sparks, giant sparks, huge amount of voltage, and can destroy or turn on electronics at a distance. Whereas the Tesla coil depends on capacitors, spark gaps, multiple coils to resonate and tune the circuit and adjust the voltage, a slayer exciter resonates and tunes itself without any complicated circuitry . It's an extremely simple circuit, which is why it is really popular among electronic hobbyists or beginners like me. Plus if you are trying to learn how Tesla Coils work, building and understanding how Slayer Exciters work can be helpful.


Now time for some warnings, cause why not.

This is not a perfect wireless transmission device which you could use to charge your electronics devices. It isn't even really useful in real life uses. But that is not point of this build, in fact the main point of the build is to familiarize with the basics of simple electronics. Just leaving this as a warning, because a lot of people raise their expectations too high to be disappointed too much with anything I make or show. Also I am an 11th grader, not a Graduate in electronics major, so I am bound to make mistakes, and I would definitely be happy if you help me correct them. Anyway now that the warnings are laid forth, let's keep moving.


The circuit is build based on the instructions provided by a youtuber named Ludic Science. Pay him a visit for more info, or more interesting circuits.

The instructable is divided into many short steps to make sure it is super simple to follow. The steps are divided in the following order:

1) Step 1: Watch Video!

2) Step 2: Circuit schematic & breadboard diagram.

3) Step 3: Materials.

4) Step 4-7: Making the coils.

5)Step 8-14: Making the circuit on a breadboard.

6) Step 18-22 : How does it work?

7) Step 23& 24: Troubleshooting tips and finishing words.

Alright, lets get to the build!!

Step 1: Watch the Video!!

Most of the things in the video is covered in this instructable, but if you prefer watching videos over reading instruction then watch my video! I desperately hope it will be helpful to you in some way. Also watching the video on youtube will increase my youtube views and maybe my funds for my future projects, so give it a go!

Step 2: Circuit Schematic

So here's the schematic of the circuit. I hope it could be a great aid in making the circuit, because it is really difficult to individually instruct on where to connect the wires. So try to follow the schematic if you can.

If you are having trouble understanding the schematic or its parts, then go to step 18.

Step 3: Gather the Materials!

To make it on a breadboard you will need the following things:

1) 22K Ω Resistor.

2) 2N2222 NPN Transistor. ( Any NPN transistor should work. The only problem is that if the transistor is not created to handle high current, then the transistor will heat up and melt in the circuit. So pick an NPN transistor with high current rating.)

3) Red or green LED.

4) 9 V battery & clip.

5) A plastic tube with diameter of 1-1.5 inches.

6) 26-32 gauge magnet wire ( copper wire with thin insulation). The smaller the gauge the thicker the wire is.

7) Thick insulated copper wire.

8) Breadboard.

And most importantly you will need patience. We will be coiling wires, and we be coiling for quite a while. Patience is the key, remember it.

Step 4: Let's Start Coiling! (1 of 3)

First take a plastic cylinder that is about 1-1.5 inch in diameter. It should be hollow. AND IT CAN NEVER BE ANY METAL CYLINDER. Okay start by poking a hole at the side near one of the ends of tube.

Take the 26-32 gauge wire, and pass it through the hole in the tube. Make sure to pass at least 3-4 inches of the wire through the hole. Then use tape or glue to secure the wire that is on the tube. Now start winding coils on the tube.

Coil the wire about 250- 325 times.

Step 5: Coiling Is a Pain (2 of 3)

After a few turns try to use glue or tape or something to keep the wires in place. I used nail polish to keep the wire in place. It is really important to make the coil NEAT. Do not overlap any turns, or leave gaps between turns. The glue or nail polish will be like a checkpoint so that you don't have to restart from the beginning if you mess up somewhere. It is a test of patience, I accidentally overlapped wires and it came loose, but thanks to the nail polish I didn't have to start from the beginning.

Step 6: No Pain No Gain(3 of 3)

So after coiling 250-325 times, leave about at least 3-4 inches in the end, and cut the wire. Now poke another hole in the tube, and pass the end of the wire through it. Use tape or glue to secure the wire in place. So now you will have a coil of 250-325 turns around a plastic tube, with 2 ends coming out of two sides. You can finally take a rest from coiling!

This is our secondary coil.

Step 7: Another Coiling Step.

Take a thick insulated wire, and wrap it 3-5 times around the plastic tube, in the OPPOSITE direction as the secondary coil. This is extremely important that it be wrapped in the opposite direction as the previous one. Now use glue or tape to keep it in place.

This is our primary coil.

Alright, now you are done with coiling. No more coiling.

Step 8: Breadboarding! (1 of 7)

Now let's start the breadboarding. Place a breadboard and place the transistor in the middle with the flat side facing you.

Note: If I tell you to attach a lead of one component to another component on the breadboard, just place the lead of the component in the same row as the other component. Since the horizontal rows in breadboard are connected together, placing two leads in the same row will create a contact between them, allowing electricity to flow.

If you do not know the polarity of the components, they will be mentioned in the step about how the circuit works.

Step 9: Breadboarding (2 of 7)

Now attach the 22 Kilo Ohm Resistor to the Base of the transistor.

Step 10: Breadboarding (3 of 7)

Now attach the negative side of the LED to the Base of the transistor.

Step 11: Breadboarding (4 of 7)

Attach a jumper wire from the Emitter of the transistor to the Positive side of the LED.

Step 12: Breadboarding (5 of 7)

Attach the Black wire from the battery clip to the Positive side of the LED. Attach the RED wire of the battery clip to the free end of the Resistor.

Step 13: Breadboarding (6 of 7)

Now take the wires from the primary coil, and attach one end to Collector of the transistor, and the other end to the Red wire from the battery clip.

Step 14: Breadboarding (7 of 7)

Now attach one of the ends from the Primary Coil to the Base of the transistor.

We are done with the breadboarding!! Simple, right?

If you want you could solder it, but I was too exhausted to solder.

Step 15: Let's Make It Look Acceptable (1 of 2)

Place the breadboard and the coil on top of a carboard box, wood box, metal plate or whatever makes it look like a completed project.

Step 16: Let's Make It Look Acceptable (2 of 2)

Now take a piece of aluminium foil and roll it to a ball. Then attach the free wire from the Primary coil to the aluminium ball. Place the ball on top of the tube.

Step 17: Now Let's Test It Out!!

Connect the 9V battery to the battery clip. Now bring a CFL light bulb close to the aluminium ball or the coil, and it should light up! Our tiny circuit (excluding the size of the coil) is working!! Do not keep the circuit on for too long, otherwise the transistor will blow up. If you notice any smoke coming from the transistor, disconnect the battery IMMEDIATELY.

Note: Please ignore the messy background and table.

Step 18: How Does It Work? (1 of 5)

Let's familiarize ourselves with the components.

Transistor: A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit. (Wikipedia). Our transistor is Bipolar Junction(BJT) , NPN type, which means a P-layer of semiconductor is sandwiched between two N-layer semi conductors. The BJT transistor that we are using has three pins, when the flat side is facing you, from left to right the pins are Emitter, Base, Collector.

The Emitter and Collector is like a variable resistor, with the knob to change the resistance being the Base. Usually the transistor stays in its Maximum resistance state, so the resistance between the collector and emitter of the transistor would be too high for any amount of electricity to pass through. But when there's a voltage at the base of the transistor the resistance between the emitter and collector decreases to allow electricity to flow through. So the base is like a switch, if you turn on the switch by applying a voltage at the base, current can flow through the collector and emitter. Now an NPN transistor requires a positive voltage at the base to go into least resistance mode, while

a negative voltage is needed if it is a PNP transistor.

LED: Light Emitting Diode, known as LED, are diodes that produce light when current passes through them. The smaller lead of the LED is negative. On the schematic, the LED looks like an Arrow hitting a wall, with two more arrows pointing outward. The side with the arrow is the + side.

Resistor: Now a resistor is simpler since it has no poles. You could connect it either way. A resistor is just any material that resists flow of electricity to a certain degree. The resistance of a resistor is shown through the color bands on the resistor. Use this to calculate the resistance of a resistor of unknown value:

Note: These two images aren't mine.

Step 19: How Does It Work? (2 of 5)

Alright, I will be using strictly Conventional Current to talk about this circuit. It will be mostly analogies, not equations or details. If anything is mistakes, please help me correct it.

So let's go one step at a time. So here we have a circuit, the + of the battery connects to - , with a transistor in between. Since there is no voltage at the base the transistor has maximum resistance between collector and emitter. So current can't flow through the transistor.

Step 20: How Does It Work? (3 of 5)

Then we attached a resistor from positive of the battery to transistor's base. Electricity can flow through the base to the emitter to the negative of the battery.

Step 21: How Does It Work? (4 of 5)

Then we added a primary coil of 3-5 turns. Current flows through that, and the wire produces a magnetic field. ( Flowing charges produce magnetic field.)

Step 22: How Does It Work? (5 of 5)

Then we attached a secondary coil to the base of the transistor, and then we attached LED between base of transistor to the negative side of the battery.

Since the primary coil produced a magnetic field, it induces electricity in the secondary coil. (Conductors moving through a uniform magnetic field, or stationary within a changing magnetic field, will have currents induced within them.) When current flows through the secondary to the top, it creates a 'vacuum' of charge. To fill that vacuum, current flows through the resistor up the secondary coil. Current is also pulled through the LED to the secondary coil, lighting up the LED a few times. Electricity tends to take the easiest path or the path with least resistance, so instead of having to go through the 22K resistor to the base, it mostly goes through the LED to the Secondary Coil. So in the end, very little current can go to the base of the transistor, and the 'switch' turns off, and the resistance between collector and emitter goes back to its maximum state. The process restarts, and the circuit keeps turning on and off by itself, really rapidly.

Now the primary coil has only 3-5 turns, and the secondary coil has 250-325 turns. It works like a transformer, the 9 V in the primary coil is stepped up to hundreds of volts in the secondary coil due to the high ratio between secondary coil winding to primary coil winding. This high voltage is enough to excite the fluorescent materials in the CFL bulb.

Our circuit also has a capacitor, a parasitic capacitor, which is also known as stray capacitance since its not intentionally created, it's just there. This capacitor connects between secondary coil to ground. This means that secondary coil isn't open, current can flow through it.

If you thought my explanation was horrible, then check out this instructable which has extremely detailed and well described explanation of the circuit : .

Step 23: Troubleshooting Tips

So in the next few paragraphs I will try to solve a few of the problems you might be facing while making it.


Solution: Calm down because I don't have either the patience or the sadistic nature in me to make someone waste hours of their youth to make a fake circuit. Let's slow down and get along with the rest of the problems. ( This happened to me countless times on youtube, people blaming me for their circuit not working.)

Problem 2: The Circuit doesn't work, would you help me fix it?

Solution: This is a better way to express your opinions and needs. Alright the circuit may not be working due to several reason. Did you make your connections properly according to the schematic? Check it. Did you properly remove the insulation from the ends of the coil? Because a lot of times people don't do it and magically their circuit doesn't work. Did you insert the transistor in the right orientation? Check to make sure the flat side is facing you, then the pin layout will be Emitter , Base, Collector from left to right . Did you use an NPN transistor? If you use PNP you will have to change the layout.

Problem 3: My transistor heats up too much!

Try using a heat sink to reduce the heating issue. Or use a transistor with higher current rating. Or try putting TWO transistor in parallel, this will divide the current, and reduce heating issue. Or use a resistor of higher value.

Problem 4: My LED doesn't light up.

Solution: Its alright if the LED doesn't light up, mine didn't either.

Problem 5: It doesn't light up the CFL.

Solution: Try flipping the wires from the primary coil connection.

Problem 6: It still doesn't work.

Solution: Life is difficult, and it is okay to accept defeat sometimes.

Step 24: Finishing Words

Alright I am almost running out of fumes.

I hope you guys found this circuit interesting and maybe want to try recreate it too. If so, then my writing this instructable was successful. Once again I am an amateur in electronics, and definitely could make mistakes. I would appreciate anyone fixing the mistakes for me. Help me improve the explanation of how this circuit works if you can. Thank you for reading and hope you have a good day!

3 People Made This Project!


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Question 4 years ago on Introduction

So I managed to snap my mag wire about 250 turns in. Can I solder the ends and continue on?

Doktor Jones
Doktor Jones

Answer 1 year ago

Not that you're still working on this, but for anyone else still looking at this, no that's not a good idea. Magnet wire is enameled so the electricity can't short across the windings; the best you might be able to do is sand down both ends where it's snapped, carefully and precisely solder so it's as small of a lump as possible, wind the lump around your core, and then coat it in nail polish so at least the outside of it is non-conductive.


Tip 4 years ago

2n2222a is not suitable for this circuit. Try to use a power npn transistor like bd535,tip31c

Doktor Jones
Doktor Jones

Reply 1 year ago

For an amateur circuit, a 2N2222 is sufficient. Specifically the 2N2222 because it's a particularly durable construction that allows it to survive in projects like this at least for a shorter period of time; that's why subbing out something like a BC337 won't go well.

Of course if you want something that's going to run for extended periods of time, or have a MTBF > a few tens or hundreds of hours, you'll want to swap out the 2N2222 for a beefier NPN... and probably also swap out the battery for a stable power supply while you're at it. But for a classroom demo/science project/amateur experiment/etc they're fine.


1 year ago

Does ANYONE KNOW which end of the bigger outer coil should I be soldering my resistor to?? The video I used as my design basis for my SEMESTER PROJECT AND FINAL shows it being connected to the bottom in video but looks like its DEFINITELY connected to the TOP of that coil in the still photo... the other end being connected to my transistor. We did not learn about transistors though, as I'm not in any regular electronics courses. I did ask the author/person who posted this to begin with but if any of the folks who have commented or who read this have a g input, if would be refreshing to have someone be of help, just to help! Please and thank you in advance. Covid really screwed us (students), especially those like myself who CHOSE HANDS ON TRADE PROGRAMS due to NOT liking regular classes and learn better HANDS ON. BUT COVID-19 MADE EVERYTHING REMOTE, &WE HAD NO PRACTICUM AT ALL. Such a let down. Now without having so much as a single in person lab, I'm expected to create my own electricity 1 way or another.... ughh I chose the Tesla Coil not realizing HOW DIFFICULT the winding of the secondary coil alone is! So please, is A YONE XAN BE OF ASSISTANCE. AND THANK TOU SO SO VWRY MUCH IN ADVANCE TO ALL!

AH Electronics
AH Electronics

Reply 1 year ago

Hey, I haven't been much active on this website for a while, but logged on just in time to see this. As for your question, it doesn't matter much which end of the bigger coil you connect to the capacitor. This is a very forgiving circuit. The only thing that might matter is the direction of the winding of the bigger coil vs the smaller coil ( so counterclockwise or clockwise). So if your circuit doesn't work, just switch the ends of the bigger coil that you connected to the transistor, or alternatively you can switch the connections of the smaller coil. It is a hard time for hands on learning when you can not be present in lab because of covid. Also there is a youtuber named Great Scott who provides excellent beginner friendly tutorials on electronics, you could use that to learn more on your free time. Stay safe and best of luck with your project.


Reply 1 year ago

THANK YOU SO MUCH FOR YOUR REPLY!!!! I really thought it was a "stretch" reaching out, as most threads I find are years old, even the youtube videos.... Okay Thank you so much!! I was careful to ensure that the outer coil was wound correct (like direction wise, but God only knows since like I said I never noticed once the video ran he never showed his connecting the negative of the power supply to the transistor so I already had to do some "fill in the blanks" HAHA And THERE ARE SO MANY DIFFERENT DESIGNS and they ALL seem to have WAY TOO MUCH POWER for my school to EVER LLOW me to work with, or that I SHOULD or would WANT TO WORK WITH! The first video schematic I sent to my Professor to ask about where to find the Power Supply and he said they were "very hard to come by" found in "old television sets and such" and usually used to power 8kV-16kV of Power he said!! LOL I was like ummmmm yeah will try to find another design. I was so sad because THAT one had GREAT instructions with the video and he seemed to reply to LOTS of the people who commented or asked questions.

Thank YOU Again. Yes, COVID and lack of being ON CAMPUS, IN LAB, or HAND-ON is SO DIFFICULT!!! Especially when I waited 15YEARS to return to College KNOWING I wanted to be in a HANDS-ON Trade and then BOOM Hi COVID!!

You rock and must be very smart to have successfully done this in High School. WOW. I never learned ANYTHING that would have aided me in making something of this nature in HIGH SCHOOL! Really Cool. Thanks again for your feedback. I do appreciate it, and I will search for that person you named on youtube too! Take Care!!! Thanks again, stay safe!!! :)

Doktor Jones
Doktor Jones

Reply 1 year ago

FYI a more commonly used transformer for such purposes can generally be found in a broken microwave as well. Old TV flyback transformers are a better source (usually higher voltage; 2-4kV vs 10+kV) but are definitely harder to come by. If you're particularly industrious enough (and careful enough) though, you can take a microwave transformer and unwind some of its primary to get a higher output voltage.

Doktor Jones
Doktor Jones

Tip 1 year ago on Step 8

While the instructions indicate "horizontal" rows in the breadboard are connected (which is true, a breadboard's orientation is generally considered with the center "valley" in vertical orientation), the picture above the instructions show the breadboard sideways - so the connected rows actually run vertically as shown in the picture. And of course the rows are not connected across the valley either.

If you look at the images with steps 8-14 it should be rather self evident (otherwise all three pins of the transistor would be connected to each other, and not much else other than one of the legs of the coil -- and the battery connector would be short-circuited 🔋🔥!

Just wanted to clarify this for anyone who might end up printing the instructions without pictures for whatever reason!


Question 1 year ago on Step 2

Would a IXGX75N250 Transistor work in a slayer circuit? It has 2500v 75a limits ?


4 years ago on Step 22

How a DC voltage source can create the transformer action? And can you please help me with the calculation part of the output part?


Reply 2 years ago

1st Answer:The DC voltage can create the transformer action on the coil because the transistor that is oscilating.
2nd : To calculate de output part is simple, I will show to you an exemple that you have the primary with 3turns and the secondary with 300turnsand the circuit is being powered by a 9V power source: 300/3=100=1/100=1:100 1:100==>9:xxx 9*100=900 1:100==>9:900 soo you have an output voltage of 900V, and current... ex.900mA ==> 900/100=9 Isecondary=9mA(0,009A).


2 years ago

Is the insulated wire of the primary coil a single core wire?

Asher Chung
Asher Chung

Reply 2 years ago

I don’t think so.


Question 3 years ago on Step 4

i have to join two wires in the secondary coil. so i have to solder them. there is some space btw them. my tesla coil is also not working what to do but the transistor is heating.


3 years ago on Step 23

If the circuit works and the LED does not light up, the LED is inverted (or burnt). More primary turns help in decreasing the heating of the transistor.


3 years ago on Step 22

The current through the secondary coil initially reinforces the current through the resistor. Just half cycle later it cuts the transistor conduction and lights the LED. The resistor just acts in the startup. It can be even disconnected when the circuit is oscillating.


3 years ago on Step 7

The directions are not important. Just switch the connections of the primary coil if it does not work.


3 years ago

Hi All,

I need help! I can't figure this out! I've repeated my steps again and again, but can't get the bulb to light up. Attached is an image of the schematic (sans switch) and a picture of my setup.

Here are the things I used:
- PVC pipe 6" long, 1" across
- 32AWG magnetic wire for secondary coil
- 18AWG wire for primary coil
- 2N2222A capacitor
- 22K Resistor
- 9V battery

The LED lights up - ie. a circuit is good.

What am I doing wrong?!?!
Thanks for your help


4 years ago

Very nice explanation.Thank you i found it here:-)