Instructables

Building the poor-mans mini tesla coil ( slayer exciter )

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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.

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)--------------(less than an inch (still wireless!) )

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 cutters

►make the following electronic equipment go crazy:
● calculators
● watches
● digital clocks and alarms
● things with capacitive touchscreens (PlayStation VIVA's, smartphones, feature phones, tablets)
● UHF remotes

make wacky sounds with:
● AM radio
● FM radio

Here is how to make a more powerful exciter (These videos were made awhile after this intructable, so the only issue with it is thermal management.)

 
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dshah245 days ago

Hey i am using laptop charger for power supply with o/p specification (19.5V and ~3.5A ) and coil specification (L1 turns=7 and L2 turns ~ 700 ) but still it does not give me satisfactory result. Can you suggest any solution???

Thank You...

-max- (author)  dshah245 days ago

Try adjusting the number of turns of the primary L1, also try a lower value resistor and a different capacitor. Watch the video for troubleshooting, I think I mention what you can do to have better performance. Although the circuit takes 5 minutes to build, it can take hours tring to make it work well.

I found that if you add a top load, make sure the magnet wire if not sizzling to the top load, and instead has a good solid connection to it.

chargers like those tend to have smart circuitry in them that make overcurrent protection constantly shut off the supply. It is annoying, as I had that problem with using a xbox 360 power brick as a 12V lab supply. I had to install a mod wire inside that completely shorted an optocoupler to a +5V rail, completly bypassing a custom safety chip.

-max- (author)  dshah245 days ago

Try adjusting the number of turns of the primary L1, also try a lower value resistor and a different capacitor. Watch the video for troubleshooting, I think I mention what you can do to have better performance. Although the circuit takes 5 minutes to build, it can take hours tring to make it work well.

I found that if you add a top load, make sure the magnet wire if not sizzling to the top load, and instead has a good solid connection to it.

chargers like those tend to have smart circuitry in them that make overcurrent protection constantly shut off the supply. It is annoying, as I had that problem with using a xbox 360 power brick as a 12V lab supply. I had to install a mod wire inside that completely shorted an optocoupler to a +5V rail, completly bypassing a custom safety chip.

-max- (author)  dshah245 days ago

Try adjusting the number of turns of the primary L1, also try a lower value resistor and a different capacitor. Watch the video for troubleshooting, I think I mention what you can do to have better performance. Although the circuit takes 5 minutes to build, it can take hours tring to make it work well.

I found that if you add a top load, make sure the magnet wire if not sizzling to the top load, and instead has a good solid connection to it.

chargers like those tend to have smart circuitry in them that make overcurrent protection constantly shut off the supply. It is annoying, as I had that problem with using a xbox 360 power brick as a 12V lab supply. I had to install a mod wire inside that completely shorted an optocoupler to a +5V rail, completly bypassing a custom safety chip.

-max- (author)  dshah245 days ago

Try adjusting the number of turns of the primary L1, also try a lower value resistor and a different capacitor. Watch the video for troubleshooting, I think I mention what you can do to have better performance. Although the circuit takes 5 minutes to build, it can take hours tring to make it work well.

I found that if you add a top load, make sure the magnet wire if not sizzling to the top load, and instead has a good solid connection to it.

chargers like those tend to have smart circuitry in them that make overcurrent protection constantly shut off the supply. It is annoying, as I had that problem with using a xbox 360 power brick as a 12V lab supply. I had to install a mod wire inside that completely shorted an optocoupler to a +5V rail, completly bypassing a custom safety chip.

-max- (author)  dshah245 days ago

Try adjusting the number of turns of the primary L1, also try a lower value resistor and a different capacitor. Watch the video for troubleshooting, I think I mention what you can do to have better performance. Although the circuit takes 5 minutes to build, it can take hours tring to make it work well.

I found that if you add a top load, make sure the magnet wire if not sizzling to the top load, and instead has a good solid connection to it.

chargers like those tend to have smart circuitry in them that make overcurrent protection constantly shut off the supply. It is annoying, as I had that problem with using a xbox 360 power brick as a 12V lab supply. I had to install a mod wire inside that completely shorted an optocoupler to a +5V rail, completly bypassing a custom safety chip.

AnubhabC made it!7 days ago

Hey PowerMax,

I have used 2 nine volt batteries. 1 LED. about 1200 turns in L2 and 15 turns in primary coil(lower turns doesn't work properly). I am not sure of the value of the resistor i am using and no capacitor But the results are not satisfactory!

It is too weak as you can see in the images! What can i do? Whats your suggestions?? There is a detailed description here: https://in.answers.yahoo.com/question/index?qid=20...

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-max- (author)  AnubhabC6 days ago
Golden run of electronics: "Thou shall test voltages!"

The current from the batteries may not be good enough. (internal series resistance is too high) Get a multimeter and measure the voltage on the batteries. I assume they are connected in series for 18V. However, if you put a heavy load on them, It will sag much lower. If the voltage is higher than 12V, the problem is elsewhere.

For better performance, definitely use a film or ceramic capacitor. I found that this doubles the performance. Try a resistor value that is lower, around 1k-5k.

After making changes, play with the number of turns.

Im thinking of using LiPo battery to operate my slayer, what do you think?

-max- (author)  Clintonimous1 month ago
Why not? Just be careful as some of them can deliver many amps of current. Also, grounding one of the terminals to earth ground may improve the output.
Dillon123 2 months ago

tip35c works well

amousa25 months ago
Hey max, so I am trying to build this tesla coil for my school project. I have made 1500 coils on a 40 cm 1 in' pvc pipe. For my L1 I have 9 coils. I am using the 2n3055 transistor. I have connected my circuit to a 9V battery. The tesla coil isn't working can you please give me any advice. Thanks
-max- (author)  amousa25 months ago
He best way to find if it is oscillating at least is too place a neon lamp next to it at see if it glows. Your 9V battery might not be capable of delivering enough current though the circuit to gen impressive results. Check the number of windings and polarity of the L1 coil.
amousa2 -max-5 months ago
Should the 2 LED's work by the current in the circuit or should they work from the L2 coil
-max- (author)  amousa25 months ago
The LEDs are simply helping prevent large translate voltages from damaging the transistor. I found that they often burn out at higher power levels, and are unessesary. They can also serve as a simple indicator whether the circuit is osculating or not, since they do not light up otherwise.
amousa2 -max-5 months ago

Can I wind the secondary coil with multiple layers? as in once you have finished coiling the whole length of the pipe recoil over it ? would that affect the magnetic field ?

-max- (author)  amousa25 months ago

Theoretically, yes*; But realistically, no. By adding another layer of wire, the increase in the turns ratio would increase the performance, but doing this would also significantly increase the parasitic capacitance within the coil, and since the output of the coil is high frequency high voltage AC, and remembering that capacitors act like shorts to AC (or more specifically voltage transients) this will effectively reduce the output, as this parasitic capacitance is sort of like a resistor connecting the output to ground, and the higher the frequency goes, the lower this hypothetical resistance (or "Capacitive Reactance") will be.

If you lowered the frequency, than overlaying all the wire would be fine, but the permeability of air does not allow us to use low frequencies, because then there would be little energy transfer to the L2 coil, unless we add a magnetic core material, like ferrite or soft iron, but then we just end up with a homemade flyback transformer, operating at lower frequencies, and very little radiated power (which is normally a good thing, unless we want to make light bulbs work wirelessly!)

The magnetic would be just fine, as long as the wire twists around in the same direction. (Google the right hand rule magnetic field)

amousa2 -max-5 months ago
I guess this is my problem then. I have coiled a .75 cm wire 450 coils on 3 layers. I will have to recoil it again.
Thanks for your help
-max- (author)  amousa25 months ago

Oh man, thats too bad! I hope you get it to work! Also, another tip I heard elsewhere on the cybernet: do not make the L2 coil long and skinny with winds far away from the L1 coil; instead, it is better to have the wire go around a larger diameter PVC with fewer turns (same length of wire). This makes sense, since it is not really the turns ratio that determines voltage, but instead, the inductance, which is related to the amount of turns, but also other factors like the diameter, physical size/compactness of the wires, and the core material. (In our case, air.)

I think the reason why a fat, short L2 coil is better is because the top portion of the coil is physically closer to the L1 coil, which strengthens the inductive coupling between the L1 and L2. All the wire too far away from the L2 coil is just waste, because it does not build up a potential in that portion, and electrical resistance plays a bigger factor.

sebrom6 months ago
C'est dommage de devoir payer pour obtenir les PDF
IronHead1526 months ago
I hope you will respond, so here is my question: Can I use IRFP260 mosfet instead of the 3904's?
-max- (author)  IronHead1526 months ago
It is possible, however, I have a very similar IRFP250, and I could not get it to work. I saw Lidmotor on youtube has achieved it with an IRF540. A schematic I found online recently shows a 100 ohm resistor instead of a 1 megohm resistor.
mjunaid47 months ago
thanx
mjunaid47 months ago
hey im builting slayer exciter for my science feast if is give epoxy coating to my secondary coil will it effect its performance plz reply
-max- (author)  mjunaid47 months ago
It shouldn't. My sloppy coil was epoxied. The purpose of the epoxy is to simply hold it together when the temperature changes, so when it heats up, the wire won't come loose and unwrap. It did not help me too much because when it was dry and finished, my handling of it caused it to break and all the wire near the bottom came loose and it looks even worse. It is still functional though.
mjunaid38 months ago
HEY I BUILT ONE OF APPROX 800 TURNS IN SECONDARY N 4 TURNS IN PRIMARY N INPUT IS TWO 9V BATERRY CONNECTED IN SERIES MY CIRCUIT DIAGRAM BUT ITS OUTPUT IS NOT UP THE MARK. ONLY 5WATTS GLOWS N ITS RANGE IS ONLY 2INCHS
HW DO I INCEARSE ITS RANGE N OUTPUT N HW MAKE LED GLOW PLZ HELP I HAV GIVE A DEMO TO MY TEACHER ON 21-11-2013
-max- (author)  mjunaid38 months ago
Adjust the turn ratio of the primary, use larger-rated transistors, and increase voltage. a good power transistor should be able to work up >12V.
mjunaid3 -max-8 months ago
my input voltage is already around 17v im using tip41c transister with heat sink but still its same and you please tell me on what principle it works and how it works
mjunaid3 mjunaid37 months ago
HI MAX CAN U give me working of slayer exciter plz
-max- (author)  mjunaid37 months ago
I'm sorry? are you asking for a working schematic? No, not really, it is up to you to determine what you need to build this. Since everyone makes their own secondary and primary and use part they have available, everyones SEC circuit is a bit different. You just have to figure it out on your own, and experiment. It took over a day to get mine working well. Adjusting the primary number of turns can help a lot. perhaps you fried your transistor. Go pick up a 3055 at radioshack or online. (like TIP3055T or MJT3055).

Also, as a tip AVOID CAPS WHEN WRITING COMMENTS. It sounds like you're yelling at others obnoxiously.
mjunaid3 -max-7 months ago
sorry about caps n i want general principle on which works on
mjunaid38 months ago
MY CIRCUIT DIAGRAM
-max- (author)  mjunaid38 months ago
??? where?
mjunaid3 -max-8 months ago
sorry about that here
CIRCUITA].jpgCIRCUITA].jpg
-max- (author)  mjunaid38 months ago
It's fine. Make sure your wiring is the same and adjust the primary number of turns.
mjunaid38 months ago
HEY I BUILT ONE OF APPROX 800 TURNS IN SECONDARY N 4 TURNS IN PRIMARY N INPUT IS TWO 9V BATERRY CONNECTED IN SERIES MY CIRCUIT DIAGRAM BUT ITS OUTPUT IS NOT UP THE MARK. ONLY 5WATTS GLOWS N ITS RANGE IS ONLY 2INCHS
HW DO I INCEARSE ITS RANGE N OUTPUT N HW MAKE LED GLOW PLZ HELP I HAV GIVE A DEMO TO MY TEACHER ON 21-11-2013
imsajid8 months ago
Thanks... Very good Demonstration my project is working. THANKS TO ALLAH
imsajid8 months ago
How much turns of the Coil L2 and L1 Should i do for glowing a 5 Watt CFL Bulb????? Plz reply because i already made a coil of 500 turns around 1 inch diameter coil. Now tell me what should i do
-max- (author)  imsajid8 months ago
It depends on many factors. I assume you do not have an Oscilloscope, LCR meter, function generator, or other diagnostics tools. It is hard to determine your output mathematically without knowing the resonant frequency of both primary and secondary circuits (for which one must know the values of inductors and capacitors (including stray capacitance/inductance).) So, you will just have to play with different number of turns and figure out what works best. My sweet spot was 5-6 turns.
mjunaid39 months ago
hi -max-
i'm trying to make one for my science feast i hav already made secondary coil
L2 is wound around 2 feet long n 1in diameter hollow plastic tube i wanted know what are battery specification plz me
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