I need an amplifier? Noob question. Tesla Coil

Thread Starter

CosmicOrderMachines

Joined Oct 31, 2019
16
Noob question, I'm wondering if an amplifier is all I need in order to run a tesla coil with an arbitrary waveform generator. Ive seen some signal generator amplifiers. I'm actually wanting to get one custom built. But I have this very dumb question, can I use an amplifier and a signal generator to power a tesla coil. Is there any specific features I need to look out for?

I'm wanting to run the coil with high enough voltage to light up a couple plasma tubes.

What I know so far: and please correct me on anything wrong.

The gas pressure in the tubes is going to effect the amount of light.

I should run the primary with 20-40v and I was simply guessing but I would need to know my amount of windings and total configurations to confirm, that id need about 40 watts. ??

The amplifier would need to be build (I'm gonna pay someone) with the very low resistant load in mind to prevent damage. ??

Plasma tubes have huge drops in current at the point of lighting up. Meaning a special protection from that quick adjustment needs to be in place in the amplifier design.

Someone say I did a good job.

Thanks for all the feedback. This community is great
 

Marley

Joined Apr 4, 2016
334
Tesla coils are resonant - they are a tuned circuit using the inductance of the winding and the capacitance between the top and ground. They are "kicked" into oscillation by the pulse of energy switched by the spark gap.

Don't think an amplifier will help you here.
 

Thread Starter

CosmicOrderMachines

Joined Oct 31, 2019
16
If my pulse is arbitrary in form, yes, but still a quick pulse, I dont see why for the most part a tesla coil can still be operated? If there is distortion effects of the coils shape or something I dont know, I understand that, but in general whats wrong with a little custom shape as you prefer to achieve specific results in the electric field?

I guess mostly, my concern is in being told amplifier wont work. Guess I really thought it worked that way after seeing small 9v batteries on a slayer circuit do just fine. If I instead used signal generator to find resonance? Where am I going wrong?
 

MisterBill2

Joined Jan 23, 2018
4,897
If my pulse is arbitrary in form, yes, but still a quick pulse, I dont see why for the most part a tesla coil can still be operated? If there is distortion effects of the coils shape or something I dont know, I understand that, but in general whats wrong with a little custom shape as you prefer to achieve specific results in the electric field?

I guess mostly, my concern is in being told amplifier wont work. Guess I really thought it worked that way after seeing small 9v batteries on a slayer circuit do just fine. If I instead used signal generator to find resonance? Where am I going wrong?
Because a Tesla coil is a resonant system, what you will discover is that if you drive it with some sort of pulses you will have a since wave response, but it will not be as great as if you drive it with a sine wave. That is how resonance works.

What is the reason for considering driving a Tesla coil with other than a sine wave? Are you intending to modulate the emissions from a plasma tube? Certainly a modulated high voltage can be produced, but it will not be from a Tesla coil. High voltages being modulated for gas lasers was done by home experimenters back in the vacuum tube era. Both the high voltage and the modulation of it are well understood, but they do not involve Tesla coils.
In fact, very high DC voltages were produced by tube type power supplies for TV sets back in the early 1950's, and that information is still available today.
 

Thread Starter

CosmicOrderMachines

Joined Oct 31, 2019
16
Because a Tesla coil is a resonant system, what you will discover is that if you drive it with some sort of pulses you will have a since wave response, but it will not be as great as if you drive it with a sine wave. That is how resonance works.

What is the reason for considering driving a Tesla coil with other than a sine wave? Are you intending to modulate the emissions from a plasma tube? Certainly a modulated high voltage can be produced, but it will not be from a Tesla coil. High voltages being modulated for gas lasers was done by home experimenters back in the vacuum tube era. Both the high voltage and the modulation of it are well understood, but they do not involve Tesla coils.
In fact, very high DC voltages were produced by tube type power supplies for TV sets back in the early 1950's, and that information is still available today.
Thank you.

Thank you for your wisdom.

I certainly have a picture in my mind of sine waves working best for resonance. (Thanks for that) I'm not looking for any kind of perfect resonance. As I see it by this view of perfect resonance any modulations done over a tesla coil are impossible or require specific geometries of the coil itself?

You're correct. I am intending to modulate emissions from plasma tubes. Part of the whole project is to have the large electric field modulated in resonance with the plasma.

Because I have little experience with a tesla coil, do you think a amplifier (near resonance sine wave) but with my wave. Would be enough to drive it to some decently high voltages?
 

Ylli

Joined Nov 13, 2015
878
A "Tesla Coil" is nothing more than a high turns ratio transformer with a resonant secondary. To get high voltages, the 'Q' of the resonance must be *very* high. In other words, the resonance is critical - driving it with 100 KHz might be right on and you get 10KV - driving it with 99.5 KHz might only give you 1 KV. By hitting the coil with a narrow high energy impulse, you allow the coil to 'ring' at its natural resonant frequency and that will give you the greatest output.
 

MisterBill2

Joined Jan 23, 2018
4,897
Thank you.

Thank you for your wisdom.

I certainly have a picture in my mind of sine waves working best for resonance. (Thanks for that) I'm not looking for any kind of perfect resonance. As I see it by this view of perfect resonance any modulations done over a tesla coil are impossible or require specific geometries of the coil itself?

You're correct. I am intending to modulate emissions from plasma tubes. Part of the whole project is to have the large electric field modulated in resonance with the plasma.

Because I have little experience with a tesla coil, do you think a amplifier (near resonance sine wave) but with my wave. Would be enough to drive it to some decently high voltages?
The 1952 vintage television second anode oscillator type supplies delivered about 10,000 volts DC. They were a stand-alone part of the set, using only 6 volts for the tube heater and about 250 volts for the oscillator plate supply. The rectifier tube was usually a type 1B3, with the heater voltage coming from a 2 turn winding on the oscillator coil.
 

Thread Starter

CosmicOrderMachines

Joined Oct 31, 2019
16
A "Tesla Coil" is nothing more than a high turns ratio transformer with a resonant secondary. To get high voltages, the 'Q' of the resonance must be *very* high. In other words, the resonance is critical - driving it with 100 KHz might be right on and you get 10KV - driving it with 99.5 KHz might only give you 1 KV. By hitting the coil with a narrow high energy impulse, you allow the coil to 'ring' at its natural resonant frequency and that will give you the greatest output.
Thanks for that. So its completely achievable to run a signal generator through a amplifier, and tune into the resonance. In this case, instead of using sine wave using a short pulse arb wave. Achievable right?
 

MisterBill2

Joined Jan 23, 2018
4,897
Thanks for that. So its completely achievable to run a signal generator through a amplifier, and tune into the resonance. In this case, instead of using sine wave using a short pulse arb wave. Achievable right?
If you use a pulse that is less than half a cycle and drive the amplifier far enough into conduction to provide the required power, and if you then tune the transformer to resonance that should work. But noth that working at resonance will tend to create a sine wave from those pulses. That is known more commonly as a class "C"amplifier. There is a huge amount of information available about class "C" amplifiers.
 

Castrol

Joined Feb 15, 2020
7
If my pulse is arbitrary in form, yes, but still a quick pulse, I dont see why for the most part a tesla coil can still be operated? If there is distortion effects of the coils shape or something I dont know, I understand that, but in general whats wrong with a little custom shape as you prefer to achieve specific results in the electric field?

I guess mostly, my concern is in being told amplifier wont work. Guess I really thought it worked that way after seeing small 9v batteries on a slayer circuit do just fine. If I instead used signal generator to find resonance? Where am I going wrong?
You won't be able to understand the concept if you don't have a look at the Fourier analysis theory.
According to that theory every signal of any shape can be decomposed to a number of sine-waves which added toghether form the original signal. So a square wave is exactly what you obtain if you sum a lot of sinusoidal waves at different frequencies.
The concept of resonance is tied with sinusoidal waves, in every field of the science, even speaking of mechanical systems.
You build a circuit with inductors and capacitors and that circuit will have one or more resonant frequencies. If you put in that system a square wave you may see a resonant effect but that will be related only to the few frequencies of your square wave that are identical to the resonant frequencies of the system. This implies that most of the square wave energy that is carried by all the other frequancy-sine-wave components is not involved in the resonant effect, so you basically are wasting that energy, you are not using that to exite the resonance.
this is why you prefer to generate a single frequency signal, i.e. a sinusoidal wave, and put all your energy in that wave, being sure you will use all the energy you are producing and obtaining the maximum effect.
 
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