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I have built a Slayer exciter using a 2N2222, with a 22 kΩ resistor, as well as the other needed components. (4 turns primary, 475 secondary.)

It works fine with a 2N2222, but I was wondering if it could work with a MJE3055T or a TIP31C.

I’ve tried exchanging the 2N2222 with these two, in the same spot. All that happens is that no power is drawn until a voltage around 9-10 V is given to it. Then it dramatically increases the amount of power going into it, but it is just heating up the transistor.

I’ve tried a variety of different resistances and numbers of primary windings. I’ve also flipped the polarity of the primary windings.

Is there something I’m overlooking?

ocrdu
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BallerSicarius
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    Those are power transistors that don't have nearly as much gain as the 2N2222. They won't self-oscillate in this circuit. – Dave Tweed May 28 '22 at 00:55
  • @DaveTweed Ah, I’ve seen the MJE3055t and TIP31c used in some similar circuits and thought I would try to and use it and see what would happen. Would you know any higher powered alternatives to the 2n2222 with similar characteristics? Thanks! – BallerSicarius May 28 '22 at 01:18
  • @BallerSicarus, can you point us to a web page showing the circuit you are talking about. Perhaps you can add an MJE3055 along with the 2N2222 like in a darlington configuration. Show me the circuit, I'M pretty confident I can fix your problem. – Fred Cailloux May 28 '22 at 01:24
  • @FredCailloux - [Tutorial / Circuit](https://hackaday.com/2020/03/21/compact-slayer-exciter-for-your-high-voltage-needs/) - A tutorial showing a person using dual MJE3055t’s as transistors for a pancake version of the slayer exciter. Mine is exactly the same as this (except for primary and secondary windings), except on a breadboard. Could doing it on a breadboard be effecting it? Using a darlington configuration may also work too, i’ll test it soon. Thank you. – BallerSicarius May 28 '22 at 01:41
  • @BallerSiracus, check this answer: https://electronics.stackexchange.com/questions/209109/tesla-coil-miniature-model-slayer-exciter-parasitic-capacitor . One possible reason it's not working may be that you have the wrong coil polarity. There are two wires per winding. Notice the two dots on the schematic, they mean the relative "polarity" from one coil to the other. Not respecting those "polarity" (for lack of a better term) is enough to make your circuit not running. Try changing the polarity of one(1) only coil. Other than that this circuit seems quite ok to me. – Fred Cailloux May 28 '22 at 02:02
  • Are you actually using 2x 9V batteries. That is what the "Instructable" page is showing. Perhaps a 9V may limit the transistor current to an unacceptable limit. – Fred Cailloux May 28 '22 at 02:04
  • https://www.instructables.com/How-to-Build-a-Slayer-Exciter/#:~:text=A%20Slayer%20Exciter%20is%20an,similar%20to%20a%20Tesla%20Coil. – Fred Cailloux May 28 '22 at 02:04
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    I’m using a lab power supply to supply it , so i don’t believe that is an issue. It’s quite annoying but i’ll wait for another shipment of 2n2222’s tomorrow to try and run them in a darlington configuration! I’ll continue tinkering with the amount of primary windings and resistance of the circuit. I’ll reply back if I can get it working, thank you for your time!! – BallerSicarius May 28 '22 at 02:32

2 Answers2

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All you need is over-unity current gain with 0 deg phase margin for the circuit loop to oscillate. (that means positive feedback at some frequency.)

But without details, we cannot speculate except that Power transistors with hFE in the 40 Range cannot compare with the 100 to 300 range @ 100 mA of a 2N2222A. Thus a different turns ratio is needed or a method of coupling enough feedback to use your circuit.

Don't reverse the coil from the design. That will just make it negative feedback instead of positive AC feedback which is needed to make it oscillate.

You could try using the power transistor as an emitter follower or Darlington pair with the 2N2222A, but that will be less efficient.

Tony Stewart EE75
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Tried that "thing" until it works ...
It seems that "one" "key" for working is ... also the capacitor between secondary and primary.
here is the "modified" schematic model ...
And some values of components don't work.

enter image description here

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And here is another configuration ... more "sinusoidal" ...

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Or something as this ... (not all power "variables" checked)

enter image description here

And here with a 2N3055

enter image description here

Antonio51
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