Slayer exciter circuit not working properly

Thread Starter

EthanWu0131

Joined Jan 16, 2024
22
Hi, this is my first time posting here, I was trying to build a slayer exciter circuit, and had some problems.

Here are my components:
- 33 SWG magnet wire as secondary coil with 300 turns
- 21 SWG magnet wire as primary coil with 3 turns
- 22k ohm resistor
- 9V battery
- KN2222A transistor(I see most people use 2N2222, but I believe they are the same besides packaging)
Also I followed this schematic(I used a LED as the diode):Screenshot_2024_0115_235222.jpg

My problem is when I connect the battery the LED(diode) lights up, but when I put a florescent bulb near the coil the bulb doesn't light up.
I read online that if the LED(diode) lights up that means the circuit is oscillating as normal, so I guessed the problem is with not enough power, but I am certain I have more than enough power, so that lead me here.
If anyone has any idea of how to fix this or what's wrong, please let me know, my goal is for the florescent bulb to light up, thanks!
IMG_20240116_205315.jpg
IMG_20240116_205251.jpg
These are the circuits, hope it helps.
 

Alec_t

Joined Sep 17, 2013
14,377
Welcome to AAC!
1) It's hard to tell from your pic, but according to this datasheet your transistor connections appear wrong.
2) have you removed the enamel insulation from the ends of your magnet wire?
3) Is the polarity of your LED correct?
4) With only 3 turns on the primary coil the current drawn from the battery amounts to almost a short circuit current. That poor little battery may not be able to cope.
 
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Thread Starter

EthanWu0131

Joined Jan 16, 2024
22
Welcome to AAC!
1) It's hard to tell from your pic, but according to this datasheet your transistor connections appear wrong.
2) have you removed the enamel insulation from the ends of your magnet wire?
3) Is the polarity of your LED correct?
4) With only 3 turns on the primary coil the current drawn from the battery amounts to almost a short circuit current. That poor little battery may not be able to cope.
I double checked the connections and they are correct, and both ends of the paint are removed, also I saw other people use the same 3 primary coil setup, that's why I was confused when it didn't work. I'll try redoing the secondary coil and see if it changes anything. Thanks for replying.
 

MisterBill2

Joined Jan 23, 2018
18,984
Welcome to AAC, we have a lot of experience helping folks with this really poor designed circuit. AND it is a very poor design by any standard.
Look at the circuit shown in post #1 and see if there is any way that there will be positive feedback to the transistor base, which is needed to support oscillation. That basic flaw in the circuit is in addition to the other things pointed out in the previous posts.
Any possible feedback depends on the arrangement and conditions not mentioned at all. When the phase relation between coils matters, competent designs always identify it, which is not ever done with this circuit.
For rewinding the coil, in an actual TESLA COIL, the driving and feedback coils are at the bottom of the secondary coil. And the secondary is a single layer of wire..
 
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Danko

Joined Nov 22, 2017
1,843
@EthanWu0131
Voltage polarity in your circuit is reversed. Exchange wires from battery.

When the phase relation between coils matters, competent designs always identify it, which is not ever done with this circuit.
There exist four variants of right connections.
All of them human can imagine mentally, using phase dots:
1705440793578.png
So, leads HV and C are on one side of coil, but leads B and + located on other side of coil,
therefore possibility of wrong connections eliminated.
 
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MisterBill2

Joined Jan 23, 2018
18,984
OK, yes, there may be different ways to get the correct feedback polarity.. Ans just as many ways to get it wrong. Of course, the capacitance between the drive coil and the secondary will also affect the feedback amplitude quite a bit.
 

Thread Starter

EthanWu0131

Joined Jan 16, 2024
22
@EthanWu0131
Voltage polarity in your circuit is reversed. Exchange wires from battery.



There exist four variants of right connections.
All of them human can imagine mentally, using phase dots:
View attachment 312880
So, leads HV and C are on one side of coil, but leads B and + located on other side of coil,
therefore possibility of wrong connections eliminated.
I followed the fourth picture's polarity, and also redid the secondary coil(350 turns), but it still doesn't light up the florescent lamp, also the LED on the breadboard doesn't light up anymore, what did I do wrong ?

(I mad sure to remove the insulation layer, and I think I have everything connected correctly.)
View attachment 312924IMG_20240117_180042.jpgIMG_20240117_180024.jpg
 

MisterBill2

Joined Jan 23, 2018
18,984
Certainly that is a much better coil. BUT what did any instructions say about the position of the drive coil on the secondary? Also, yhe picture looks like the primary and secondary wires might be touching close to the breadboard connection.
AND still, there is no intentional feedback loop to make it oscillate.

The "Slayer" circuit is still in the class of BLOOPER oscillator circuits. That has not changed.
You could add a feedback winding of a few turns and make it into a HARTLEY oscillator that would work quite well when you got the feedback polarity correct.
 

Thread Starter

EthanWu0131

Joined Jan 16, 2024
22
I
Certainly that is a much better coil. BUT what did any instructions say about the position of the drive coil on the secondary? Also, yhe picture looks like the primary and secondary wires might be touching close to the breadboard connection.
AND still, there is no intentional feedback loop to make it oscillate.

The "Slayer" circuit is still in the class of BLOOPER oscillator circuits. That has not changed.
You could add a feedback winding of a few turns and make it into a HARTLEY oscillator that would work quite well when you got the feedback polarity correct.
I thought the one end of the secondary connected to the base is the feedback, and that is enough to keep the circuit oscillating, I compared my circuit to https://www.instructables.com/Slayer-Exciter-Circuit-Poor-Mans-Tesla-Coil/, and I believe they are pretty much the same, or am I wrong ?
 

Alec_t

Joined Sep 17, 2013
14,377
AND still, there is no intentional feedback loop to make it oscillate.
Feedback is by direct connection of the secondary to the transistor base, as per post #1. Intentional or inherent capacitance forms a tuned circuit with the secondary.
The circuit may not be ideal, but LTspice says it does oscillate.
The "Slayer" circuit is still in the class of BLOOPER oscillator circuits.
Why?
 

Danko

Joined Nov 22, 2017
1,843
Second winding of coil seems good.
Primary winding should be made from plastic insulated wire and looks like:
1705496030236.png
Wire at a14 must be moved to a16.
Wire from b16 move to b14.
LED should be connected between e11 and e15.
 

Thread Starter

EthanWu0131

Joined Jan 16, 2024
22
Hi, I swapped the wires as @Alec_t suggested, and I find tiny arcs between the primary and secondary coil, does that mean the coil is working and I just need to change the primary to a better insulated wire like @Danko suggested ?
 

Danko

Joined Nov 22, 2017
1,843
Hi, I swapped the wires as @Alec_t suggested, and I find tiny arcs between the primary and secondary coil, does that mean the coil is working and I just need to change the primary to a better insulated wire like @Danko suggested ?
Your circuit already oscillates.
Only need to good insulated wire for primary winding.
ADDED:
These arcs are very dangerous, because they burn insulation of secondary winding wire,
so HV winding may easily be destroyed.
 
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