Mini tesla coil is not working

Aleph(0)

Joined Mar 14, 2015
597
Oh God, I have try many times, but it's still not working .... I need some solution for it. I seen some video and they did it very simply. And I don't know why ??? I try to do with the same way at the first time, I watched a lot of videos about tutorials but something wrong, something I don't know how ?
@buiquangdinh I say you could find it vry helpful reading through POST LINKED HERE .

So here's some other thoughts:
Whole trick is enhancing feedback from secondary (which as practical matter means giving it reactive load) but even radiation feedback from like _antenna action_ of wire connected to high Z end of secondary can sometimes make Osc run. Also cuz current is vry low (like < 1μA) you shouldn't expect big obvious sparks. You can get idea if it's doing anything by putting linear fluorescent lamp near secondary looking for glow in dim room! Once you see that (which means Osc is running) you can _tweak_ circuit for better performance. But just remember it's super low power circuit which is good for safety but basically vry boring for effects:(
 
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Thread Starter

buiquangdinh

Joined Jul 25, 2018
15
Hi everyone, finally, I'm done. Its worked. But it still have a problem. It only worked when I put a bulb touch to topper of secondary coil. The thing which I really hope is the bulb gonna light up when I bring it closer to tesla coil, it light up !. So this is my next problem which I'm facing. Any ideas ?
 

Aleph(0)

Joined Mar 14, 2015
597
Hi everyone, finally, I'm done. Its worked. But it still have a problem. It only worked when I put a bulb touch to topper of secondary coil.
@buiquangdinh That's totally typical Slayer Osc operation:cool:!

The thing which I really hope is the bulb gonna light up when I bring it closer to tesla coil, it light up !. So this is my next problem which I'm facing. Any ideas ?
@buiquangdinh Your experiment totally answers your own question:cool:! So to make oscillator run continuously u need to give it a permanent, preferably reactive, load! Like a small capacitance from top of secondary to ground:)!
 

Thread Starter

buiquangdinh

Joined Jul 25, 2018
15
@buiquangdinh That's totally typical Slayer Osc operation:cool:!



@buiquangdinh Your experiment totally answers your own question:cool:! So to make oscillator run continuously u need to give it a permanent, preferably reactive, load! Like a small capacitance from top of secondary to ground:)!
You mean a ball ? On the top of secondary ? I mean if your advice is a capacitance, Where should I do ? There is not in a basic schematic, so I don't know where to put it on .
 

DickCappels

Joined Aug 21, 2008
8,685
You might find that putting that LED back will help you get more robust oscillation since the diode clamps the fed back voltage's negative excursion, thus forcing a little more base current when the signal swings positive again. It is probably an LED since the voltage drop will be larger than a single PN junction, thus allowing fast turn-off, which is probably useful.
 

MisterBill2

Joined Jan 23, 2018
11,627
Instead of relying on a totally unpredictable and usually inadequate capacitive feedback arrangement, which it has already been presented is difficult to get working, why not use that little coil as a transformer coupled feedback winding, in the manner which Tesla coils have been designed for perhaps 50 years using vacuum tubes? There would be no dependence on the random capacitance between windings, but rather a definite feedback ratio set by the turns ratio. In addition, this approach removes the effect of whatever is connected to the high voltage winding, and allows the "bottom" of the high voltage winding to be grounded.
One more comment is that in 50 years as an electronic engineer I have never heard of the "Slayer" oscillator circuit. Hartley, Colpits, Vackar, Clapp, and electron coupled oscillator circuits, as well as crystal and phase-shift oscillators, and even tuning-fork oscillators, but never the "Slayer" circuit. So I am wondering about the origin of the circuit. Where is it published?
 

shortbus

Joined Sep 30, 2009
9,328
Instead of relying on a totally unpredictable and usually inadequate capacitive feedback arrangement, which it has already been presented is difficult to get working, why not use that little coil as a transformer coupled feedback winding, in the manner which Tesla coils have been designed for perhaps 50 years using vacuum tubes?
That is because these type of coils aren't really a Tesla coil. Not even by the largest stretch of the imagination. But due to the internet and Youtube they are now considered by many, many young and old to be Tesla coils.:(
 

MisterBill2

Joined Jan 23, 2018
11,627
The drive must be at the series resonant frequency of the secondary. Using the secondary current as the feedback signal helps to insure that it is.
It should work to connect the bottom of the high voltage winding to the top of the drive winding, which would force the oscillations to be at the secondary resonant frequency. And tuning a winding to resonance is not that hard, anyway.
 

Aleph(0)

Joined Mar 14, 2015
597
One more comment is that in 50 years as an electronic engineer I have never heard of the "Slayer" oscillator circuit. Hartley, Colpits, Vackar, Clapp, and electron coupled oscillator circuits, as well as crystal and phase-shift oscillators, and even tuning-fork oscillators, but never the "Slayer" circuit. So I am wondering about the origin of the circuit. Where is it published?
Misterbill2 what ur saying reminds me of what @Hypatia's Protege is always saying abt how she misses days when new discoveries and techniques were exclusively published in scientific and trade journals instead of informally on web often by hobbyists giving their name to variant of other ppl's discoveries w/o even knowing it! (So good example of that is Mazilli osc which is vry useful circuit but it's variant of Royer topology which I say should always be made clear!).

So anyhow FWIW just IMO Slayer Osc is basically a malformed Oudin/Royer hybrid. One thing for sure is at its current level its name isn't descriptive of shock hazard:D!

it looks like you are trying to light an incandescent lamp. You need to use a neon lamp if you want it to light when holding it near the coil.
I thought he was taking my suggestion of using linear florescent tube as indicator of oscillation? Cuz he said touching bulb to end of coil caused it to light? So it has 2b some kind of discharge lamp he's talking abt:confused:?

That is because these type of coils aren't really a Tesla coil. Not even by the largest stretch of the imagination. But due to the internet and Youtube they are now considered by many, many young and old to be Tesla coils.:(
Shortbus ur ABSOLUTELY CORRECT! I'm SO glad somebody besides me (and EHT team) care abt that! It's gotten to where any electronic circuit which produces high voltage is called _Tesla coil_ including even CD ignition circuits and blocking Osc driven TV flybacks:mad::rolleyes:! There's even a Youtube vid where a guy is calling line operated NSTs, MOTs and radiography xfmrs _Tesla_ coilso_O! So I'm vry happy Nikola Tesla is finally getting way overdue name recognition! But not like this cuz I say it's basically disrespectful to his life's work and memory for ppl to use his name w/o even taking time to learn abt him and his ideas:(!

The drive must be at the series resonant frequency of the secondary. Using the secondary current as the feedback signal helps to insure that it is.
Ylli ur totally right! That's advantage of pwr osc for PSU (in application where load doesn't care abt frequency) cuz load is just part of frequency determining network so instead of de-tuning secondary, changes in load impedance re-tune Osc so it's always automatically _matched_ to load:)! So o/c there's limits but that's basic principle:cool:!

But I totally agree with @MisterBill2 that Slayer Osc is a sorry excuse:(!

You mean a ball ? On the top of secondary ?
That's what the ball does - add capacitance.
Loading high impedance end with like ur saying foil sphere or _toroid_ might work but it's not reliable solution.

But if you want to see the circuit for a real Tesla coil go to either "thefreeinformastionsociety" website or the "schematicsforfree" website. They have quite a few circuits to look at.
Misterbill2 I SO wanted to just tell him how to build a proper DRSSTC but that's prolly not good idea with newbies cuz even getting past RF burn and fire hazards he could easily ruin every electronic device in his home or even connected to his side of distribution transformer:eek: I say TCs should only be run outdoors on portable genny!
 
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Thread Starter

buiquangdinh

Joined Jul 25, 2018
15
It looks like you are trying to light an incandescent lamp. You need to use a neon lamp if you want it to light when holding it near the coil.
Oh, thanks, I will try. But some people have tried with CBL buibl and it light up ? Why ? Might my tesla coil too weak ?

Instead of relying on a totally unpredictable and usually inadequate capacitive feedback arrangement, which it has already been presented is difficult to get working, why not use that little coil as a transformer coupled feedback winding, in the manner which Tesla coils have been designed for perhaps 50 years using vacuum tubes? There would be no dependence on the random capacitance between windings, but rather a definite feedback ratio set by the turns ratio. In addition, this approach removes the effect of whatever is connected to the high voltage winding, and allows the "bottom" of the high voltage winding to be grounded.
One more comment is that in 50 years as an electronic engineer I have never heard of the "Slayer" oscillator circuit. Hartley, Colpits, Vackar, Clapp, and electron coupled oscillator circuits, as well as crystal and phase-shift oscillators, and even tuning-fork oscillators, but never the "Slayer" circuit. So I am wondering about the origin of the circuit. Where is it published?
You right ! I've read many topics and they said its a "slayer exciter". Sorry my bad !

I d
The drive must be at the series resonant frequency of the secondary. Using the secondary current as the feedback signal helps to insure that it is.
I did, that is in basic schematic that I show before. The problem if the bulb touch to top of secondary coil => light up, if not => not light up @@. I seen many video and it's worked

But if you want to see the circuit for a real Tesla coil go to either "thefreeinformastionsociety" website or the "schematicsforfree" website. They have quite a few circuits to look at.
Thanks for your recommend, I'll read later.
 
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Aleph(0)

Joined Mar 14, 2015
597
Oh, thanks, I will try. But some people have tried with CBL buibl and it light up ?
buiquangdinh if u mean CFL it may light too but neon bulb or linear florescent is better choice cuz there's no circuitry connected to lamp possibly interfering with test! So just personally I prefer florescent to neon for purpose cuz phosphor gives more visible light for given arc energy! (UVC produced by Ne arc in neon bulb is just absorbed by glass so only visible light is dim orange-red band).

The problem if the bulb touch to top of secondary coil => light up, if not => not light up
Might my tesla coil too weak ?
buiquangdinh It's more likely Osc only runs when lamp is in physical contact with coil (by providing feedback path cuz of capacitive loading or like 'antenna action')! So if you assure oscillator is running continuously (by providing reliable feedback path) then lamp can light w/o being in physical contact with coil.

Buiquangdinh Now I have to say something! That circuit is not a _Tesla Coil_! and you should totally doubt competence and honesty of anybody or site saying it is!

Now I (and others) have already given advice on things to try to increase oscillator activity and reliability! How can we help when you just ignore our suggestions and explanations:rolleyes:?

So anyhow IMO Slayer Osc is just a vry silly toy! Plz just think on it! 2N2222 BJT is a small signal device! So even putting topology aside, anyone calling that circuit a _Tesla coil_ is like claiming a machine powered by a co2 cartridge to be a full-scale Boeing 777:rolleyes: So plz just remember sad truth abt most of YT and other demonstration sites: "50% is BS and remaining half is just plain wrong"!

So I'm not trying to discourage you at all! Just asking u to use common sense and consider the source:)! --- So like @MisterBill2 says there's plenty of reputable web resources for real Tesla coils and other HV projects!

FYI A good way to tell quality sites from BS/Expo sites is quality sites give a schematic and theory of circuit operation! If they can't or won't at least do that then they're just lazy ignoramuses only worth ignoring!

So plz keep us posted:)!
 

MisterBill2

Joined Jan 23, 2018
11,627
Like I have said previously, a real Tesla coil has a driving winding and a feedback winding in addition to the high voltage winding.
Unfortunately the websites that I suggested one has restructured itself so that I find it much less user friendly, and the other one has a very complex multi-stage thing that I would not suggest anybody try to build because it is quite complex. I have not searched for other designs but I have seen them in the past. And I will need to look up those other oscillator circuits just to see what they are. Too bad that you could not post them here.
And remember that not everything that you find on the internet is the truth!!
 

Aleph(0)

Joined Mar 14, 2015
597
Looks like OP booked? I hate it when that happens and I say it happens way too often! Cuz of lying Youtube, etc confusing newbies so they don't know who to believe or what to think:(!

@buiquangdinh If you read this plz speak up cuz I totally promise none of us are insisting that u take just our word for anything! We're totally happy to direct you to references and resources! So if you want we can help you with design advice too:)!
 

MisterBill2

Joined Jan 23, 2018
11,627
I finally visited the posting with that circuit so that I could see what was claimed to work. I have seen something similar, except that it used a tube, and it was published back about 1955 or so. The author referred to it as a "blooper" oscillator, noting that neither amplitude or frequency were at all stable, and that it often had to be tricked into starting to oscillate.The circuit shown needs quite a bit of gain in the transistor to oscillate, as well as an adequate amount of capacitive coupling to work. So just because some video claims to show it working does not mean that what shows is at all the published circuit.
So if a blooper oscillator was a poor choice back in 1955, why should it be any better now, many years later?
 
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