Tesla Coil Inquiry

Quote: Originally posted by TheAlchemistPirate

Recently I have been learning about electronics and radio technology, and other than my whims of building a long range quadcopter that piggybacks the cell tower network...

Quote: Originally posted by WGTR

If you ever do this, I'd like to see the details.

Quote: Originally posted by WGTR

The "terry filter" shown in the schematic has wires going to nowhere. I'd suggest looking for a better schematic.

I still don't understand why power pulse modulators can't be used in place of normal transformers, is it because the negative terminal receives huge voltages that it wasn't designed for? I am now looking into solid state coils since they use lower currents and don't require hard to find transformers. They all have massive circuit schematics however. I'm not looking to produce 2 foot arcs right now, I just want to actually understand how the circuit works and why each component is used. There are so many terms on java TC and such that I have never heard of. I am currently doing all the projects in the book Make:electronics but only understand basic electrical math and terms. The projects are on hold for now however since I accidentally fried all my 2n2222 transistors. The most important thing to me is to understand exactly why everything works, then I can begin my plans to rule the world.

The stun gun circuit looks interesting, and seems similar to some solid state schematics I have seen. Something that feels surreal to me in electronics is seeing all these same components over and over again, like the 555 chip, 14007 diode, 2n2222 transistor, it creates the illusion that I know what I'm doing . I wonder how long the stun gun circuit can run, maybe a long time if it is ventilated... So, if a blundering sixteen year old were to replace a stun gun button with a switch, replace the leads with a primary winding, and throw a wire-wrapped pvc pipe with a toroid on top(from a failed sstc kit from christmas-soldering sucks long story short), into the middle of it, how would it go down? What if that sixteen year old managed to calculate the general size of the required primary and secondary coils?

EDIT: I saw a project on instructables where a kid threw together a 12v power source, which went to a makeshift 555 timer which powered the leyden jar and spark gap. He indiscriminately wound a primary and secondary, and attached some sort of metal ball to the top. At first, the high voltage current went to the negative terminal of the timer circuit and blew up the 555 of course. But, to fix that, he attached a photocoupler! This kept the high voltages from affecting the rest of the circuit and still provided a ground for it. What if I used a photocoupler on the negative terminal of the power pulse modulator? Then I could drive a circuit that would normally require an NST with an accurate and multi-use power supply.



[Edited on 30-8-2015 by TheAlchemistPirate]

Quote: Originally posted by IrC

Edit to consider this: "because the way they seem to glance past something like what causes a flyback transformer to work is very frustrating to me" You, me, and all who study. In virtually everything. Something you will always deal with. Sometimes the writer assumes others know more than they do so they gloss over important points. Sometimes it is being lazy and more often than one may realize they just do not know themselves. You will always deal with this and getting good at searching, spending time in study, asking for clarification from others (as little as possible don't ask for spoon feeding in lieu of effort on your part), are a few ways to overcome this obstacle.[Edited on 8-31-2015 by IrC]

Quote: Originally posted by WGTR

Don't be afraid to blow up components, if it helps you learn.

I made some radio circuits on flattened out beer cans to get a great earth plane, and also screen the circuit when finished simply by folding the metal into a box shape and tack-soldering the edges together.

The surprise was that the solder flowed into the can material, which i assumed was Steel as it is magnetic.

Whatever it is, it takes solder really well, and it certainly isn't just Tin.

Edit:

Found some of those circuits in the junk box.

Here's some radio stuff on beer-tin ground plane with the donor material in the background :

[Edited on 31-8-2015 by aga]

Why am I not surprised that this project of yours involved beer in some way?

I've cut up metal food cans and found them to be solderable as well. They seemed to work OK for shielding purposes.

Wow. I have a lot to think about lol. The van de graaf generator is completely disassembled at this point, though the sstc has two nonfunctioning circuit boards and a badly wound secondary. I have more patience now, and should soon be getting my replacement parts for an electronics project book. As I said before I blew up(more-so popped) all my transistors. The reason I'm using 2n2222s is simply because the projects require them.
You're probably right that I need to practice my soldering, I'll try the nail thing later today. Are those radio transmitters or receivers, aga? I was intending to do the project around late fall, because my beekeeping hobby winds down around then. In the meantime I was thinking about buying a simple FM transmitter kit. I was considering trying to amplify the signal with transistors, though that might be slightly illegal .

This thread has gotten slightly off topic(not that I mind), maybe I should post later when I get a solid plan for building a coil? Or should we still talk about miscellaneous electrical things that I may need help on? You guys are very intelligent, thanks for helping.

I had ordered the 2n2222s long before this thread even started, . These 2N3904s must be very impressive to you guys lol. But you're probably right, I should wait until I finish the electronics book (I have actually had it for 2 years). I also just remembered the negative ion generators I ordered from china a month ago...

I have spent the last year trying to become more competent in electronics, so hopefully I will be able to get something done now .

I have a few questions I might be asking later, but this is the one which is bothering me most. To put it simply, I don't know how exactly a tesla coil works. I have read quite a few articles detailing exactly this, but they rarely seem to exactly match the actual construction of the device. Here is my somewhat simplified understanding-



There are several "things" which are now called tesla coils, and some are very different than others. What I am talking about is the closest thing to what Tesla himself created, which he did not call "tesla coils". According to what I could discover on the internet, there were several devices Tesla invented which could be called "tesla coils". They all involve two or more resonant circuits, and fairly high voltages and frequencies.

- One was an inductor connected to a capacitor bank (In series, or in parallel???) so as to form a tuned circuit, with another tuned circuit consisting of a cylindrical (air core) inductor and a roundish metal(usually) "elevated capacitance" at the top. The inductor connected to the capacitor bank surrounded the other secondary inductor, usually near the bottom. The primary circuit was the one which was powered by a high voltage and high frequency AC.



The method of how this AC was produced is a mystery to me, since (in modern designs)(and in SGTCs) the high frequency/high voltage is produced by allowing a rectified HV from a transformer to charge a capacitor bank, which periodically (usually only a few 100 times per second) discharges through the spark gap so as to "ring" the primary coil. But in many cases this same capacitor bank functions as the capacitor in the primary LC circuit! Can this same capacitor bank, which builds up the power to cross the spark gap and energize the primary coil, act as the capacitance in the same circuit? Isn't a tesla coil (at least partially) two circuits tuned to the same frequency, which requires two dedicated capacitances for each one? But how can this be possible if the primary capacitor bank is only connected to the primary inductor a few 100 times per second? These systems usually are supposed resonate at hundreds of kHz aren't they?

I hope I am making sense, I'm trying to know exactly what is happening in these devices. Another issue is I cannot determine whether the primary capacitor bank should be in series with the primary inductor, or in parallel. I have seen both configurations, and while I am new to this realm of electronics, I think there could be a large difference in operation.

What if a pair of resonant circuits could be built so as to resonate at a frequency such as 10 kHz? I know this might be rather difficult, but perhaps the dimensions of the secondary inductor could be radically changed from the normal thousands-of-turns-using-tiny-wire type to something else. Maybe the thickness of the inductor could be increased as well as the form diameter? Anyways, if the coil resonated at 10 kHz, and a rotary spark gap was built which could achieve that switching speed, and the primary capacitance was dedicated solely to LC duty, what changes would be observed? I would like to try.


[Edited on 13-9-2016 by TheAlchemistPirate]

Ok lots of questions. I will answer some of them. I hope you have already read the many explanation you will find on the internet. I can only answer in general terms as you have not given a particular schematic your having problems with.

For a spark gap impulse type Tesla coil the primary is a tuned circuit consisting of an an inductor L and capacitance C. That C is charged by the power supply until a sparkgap SG breaks down.

While the SG is conducting the L, C and SG form a loop, a circuit with each element in series ie a tuned circuit. Near the end of the ring down the SG stops conducting and the loop is open circuit so no tuned circuit but then its not required. In fact it must open circuit to allow the C to be recharged.

Note 1: The sinusoidal ring down has a lower frequency sinusoidal profile as the energy moves between the primary tuned circuit and the secondary tuned circuit.

Note 2 : Deciding if a circuit is parallel or series must be done with respect to two circuit points so depending on which points you choose the circuit can be parallel or series.

Yes you could build a 10kHz Tesla coil but the L and C of both the primary and secondary would have to be 15 times larger than a typical 150kHz Tesla coil. Yes you could power it from in effect a 15kHz supply. I believe Tesla experimented with alternator powered coils at those relatively low frequencies.
But it would be very difficult to reach the peak powers of typical impulse coils.

The used to be apps like wintesla and probably now modern versions that allow you to design an impulse Tesla coil by inputting various parameters. In particular they calculate the approximate resonant frequency of the secondary. They would give you a good feel for how large a secondary, its number of turns and the size of the top load you will need for 10kHz.

I think you should build a pair of these LOL






[Edited on 13-9-2016 by wg48]

I forgot to mention what I am actually trying to achieve, which may affect your suggestions. I am trying to verify or dismiss some of the effects usually associated with Tesla's various devices, such as transmission through Faraday cages, or wireless power transmission. I know many of these ideas haven't actually been demonstrated (recently, at least) , but I think they are worth experimentation. These kinds of effects (according to Tesla) are disrupted by the breakdown of the surrounding atmosphere, which form the sparks many TC builders desire. My goal is not to create sparks, but to maximize the energy which is stored in the device. Another idea I have is the cooling of the device to super-low temperatures using liquid nitrogen, which might increase the power to a large extent. Tesla reportedly did this too.

This is the main reason I want to stay as close to the original designs as possible.


Back to the actual discussion--
So in a normal SGTC the primary tuned circuit doesn't have to exist constantly for it to work, and the primary capacitor can function as both a part of the switching mechanism and the primary tuned circuit? After the primary tuned circuit "rings down" , and the spark gap is extinguished, does the secondary tuned circuit store the remaining energy? Or is the resonant energy of the secondary tuned circuit dependent on the primary tuned circuit being present? What I'm trying to ask is if the secondary LC can store energy without the existence of the primary LC.

But this might be where my plans differ from many other TC plans. Since most TCs are designed solely for the creation of large sparks, the peak voltage would probably be the main (or sole?) goal of those designs. This might not require the device to have energy in the LCs continuously, since it would be the peak voltage that matters, not the ability to build up energy. Is this what you mean by "impulse coils", because they only operate during each "push" of energy (the spark gap breaking down)?
If this is the goal of most SGTC designs, then it makes more sense to me. Or maybe the above paragraph is pure speculative nonsense . Assuming it is true, I want to try to preserve the energy from each successive "push" of energy, which might require a continuously active primary LC? Wouldn't that require the power supply to work at the resonant frequency? Of course, as we stated before, this would require large inductances and capacitances, as well as (in the case of SGTCs) high speed rotary spark gaps. I won't worry about those design challenges right now.

I will keep trying to dig up the original plans and theories, and will probably update this thread soon. Thanks for helping