Joulethief SEC exciter and variants

[sorveltaja]

Current status: I'm going to ditch that 'chopped supply' -idea, for now, as it doesn't offer the solution, that I'm after. Regardless of numerous testings.

So, back to the basic circuit:

I have dropped that cfl coil also, because it doesn't seem to make any difference. L2 and L3 are the ones, that I still use, with that spray can cap-sized L1:



One may wonder, why that capacitor bank is there, between L1 and transistor's base. It simply seems to add more 'bite' for the L1's pig tail end.

Can't explain it better, but after adding that capacitor bank, one pair after another, I got jolly good jolt, when I touched the pig tail.

Previously, similar act resulted only a smell of burning skin.

Next step might be obvious; adding more pairs of capacitors to that bank.
At this time, I have only few more left of those 1500u/6,3 caps. I would like to use all of them to increace the bank's capacity even further, but it simply isn't practical, as my breadboard gets too crowded.

Using a one pair of, say, 10000uF caps could be much simpler.

[sorveltaja]

Nick, I still use that C2655-based circuit, but this time with only one transistor.
The coils are pretty much same too. Even the transformer is same, 5V/200mA.

I have also got that 555-based (square wave)oscillator to drive 3055, which chops the exciter's power supply. I assumed, that that was the way to get bursting, pulsed output. Pulsed yes, but nothing more.

Resulting nicely flashing cfl, but generally much lower output, in form (or more of an absent) of a plasma stream.

I'm again tempted to feed much more juice for the circuit. It would require swapping back to that notorious, transistor blowing, 5V/15A, 12V/2,5A PSU.

But, I'll stick with that low-power supply for a while. After all, there is more than enough options and variables to test the circuit, and to this stage, I prefer to have a room for my clumsiness, meaning, play it safe.
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Nick, that single transistor idea sounds great. Simpler the better, but also, sometimes, when your aim is to explicitly provide a simple solution for the problem, then the plain practice steps in, and makes it a whole lot more complicated. With that, I refer to my own recent testings.

I watched your latest video, and it is definitely on my todo-list, to test the circuit with one transistor only.

What comes to your idea, about running the circuit, even without single transistor, an idea popped to my mind: coils oscillate between each other, and a transistor oscillates at a frequency, which is dictated by those coils..

So, both are depending of each other. If the transistor is eliminated, maybe the circuit needs something to match that pair of coils.

As a principle, two transistor based, self-starting multivibrator, where that pair of coils, primary and secondary, could act as a one transistor, needing a matching pair to even start..

[NickZ]

sorveltaja:
Thanks for the update. You haven't mentioned any results on your new set up.

I am also waiting for some parts to be delivered today. I could not get the 2n3055 from RS, that I need, as they are still not in stock here, so I'll have to try different transistors.
Here is an interesting video showing how the same results can be obtained using just a single H945 transistor on the Exciter tower. I really like super simple circuits, especially when they work this well. Makes me wonder if the circuit could be made to run with NO transistor even, as that seams to be the bottle neck to higher outputs.

Slayer exciter 50mm tower - YouTube

[sorveltaja]

Nick, I have tried SD13002(is it 13007's little bro?), scavenged from cfl circuit, and got rather weak results. At lower values of the resistor, that bugger gets warm, and even hot, when testing. Output is still minimal, when compared to C2655, that I have mostly used for testing.

What comes to C2655, I managed to literally explode one, after swapping that 5V/200mA printer transformer to 5V/15A PSU. Circuit ran ok with it, but, clumsy as I am, I accidentally shorted the circuit, while tinkering.

Anyways, I swapped back to that printer transformer.

Today I received the components, that I ordered last week.

Some transistors, and couple of 555-timer IC's.

So, I built a 555-based metronome(not my own design), whose output is supposed to drive the 3055.



Just to chop the exciter's supply voltage, as I mentioned earlier.

[NickZ]

I've found a power transistor that is lighting 3 leds on a single AA battery, so I know that it is working as a Jtc. But, when I place it into my Exciter circuit with or out without the 1m resistor, it won't start the circuit. It is a fast switching power transistor, #D13007 700 volt, 4 amp one. Since it works fine when using a tiny 1/2" CFL ferrite toroid core on a Jtc, I'm going to see if I can get that to work with the Exciter, as I've done that before but using that same bifilar wound toroid as a trigger coil, when using a 2n2222.

sorveltaja: You may have to just have the load and everything else ready before you turn on the power to the circuit, to avoid the no load overheating problem. An on/off switch also can help.
I put my finger on the transistor when trying new things to check the heat, but, even then I fried my share of them. Interesting how Slayer could not make the MPSA06 work on some of his Exciters, maybe the same problem that I'm seeing now with the D13007 transistor that I'm trying out.
The 2n3055 should work on 12v though, possibly depending on the circuit.

[sorveltaja]

Nick, thanks for the link, and explanation. I watched several Itsu's videos, and they are very informative. After watching them, it sort of cleared things in my mind.

What I earlier explained, about controlling the circuits fundamental, or working frequency, wasn't exactly what I meant.

Circuit/coils -composition always work at its own frequency, let it be so.

What I was after, was(is) to prevent the situation, where unloaded, or idling circuit saturates itself to the (holy?) smoke status.

Using some form of adjustable, current sensing, chopping circuit, whose frequency depends of the current, that the exciter uses, to protect from accidental shortcuts, and also from over-powered PSU, while testing.

I'm aware, that it could make the circuit more complex.

[NickZ]

Here is a video by Itsu, about woopy's Kacher replication, running a fan.
There is a lot of interesting information on this video, and other videos by him as well.
Replication of Woopy's Kacher to DC motor 1 - YouTube

Also a quote from Itsu about the heat loss, from the heating of the transistor:

"Anyway, this kacher i used has an input of 24.5V at 1.6A, so almost 40W!
Most is lost in heat (transistor) and RF (330Khz), and the fan (12V / 0.22A) runs of this RF via the antenna/ground."

Regards Itsu


Check out his other videos as well.
NickZ

[NickZ]

Sorveltaja:
There are several things that can be done to tune an Exciter. One of them is the pigtail size, and as Jonny Davro has mentioned, a magnet can also be used to tune, when an axial inductor is used for an L2.
When using two towers the distance between them is also used to tune them, as well as an aluminum block for added capacitance. The use of a ferrite rod sliding in and out of the tower(s) can also be used for tuning.
The transistor can be replaced by a diode, as the Doc has shown in one of his videos, with some success as well.
I can actually start and run my set up with no base connection at all, and it can runs just as well as it does with the two 1n4148 diodes and capacitor connected between the base and emitter.
There are some very informative videos made by Itsu on YouTube that you may want to look at, as he has done extensive experiments using many different L1 to L3 coils, antenna, ground, and components tests.

[NickZ]

I did notice one thing though that I want to mention...
It appeared when I placed the 1n4148 diode(s) on the base to emitter, I was actually able to increase the voltage output by several volts when reading between those two point with my meter. This was a bit strange, but I'm sure there is a good reason for it. It did not drop the heat though, but did increase the output voltage to higher levels previously unseen.
What I have noticed on my set up is that the wireless output, is directly proportional to the input current, not so much the voltage, but the current. So, less input current, means less gain. There may however be something different about the placement of those diodes and what they are doing, that may make a difference. Each diode will drop the voltage by about 0.7, so two of them in series would be about a 1.4 volts lower input. Which still is not enough to cure my heat problem on a fully charged 12v battery. But, it sure works nice for a little while, with wireless on an Av plug up to arms reach.
Transistor types (or mosfets) can make all the difference, also. And I did at one time have several CFLs running on 12v, with no heat, at all. So, I know that it's possible, and the loading may partly have something to do with it, although I'm useing the same load presently.
It is as you said, that the unloaded device can heat up, and even go into meltdown mode. I notice this also. But, the idea is to match the load to best suit the oscillator, so that the more bulbs that are added will actually result in higher gain, and a better and stronger output, as the Doc has suggested when using Leds strings, and not the other way around.

[Slider2732]

@Nick - yes indeed, many routes are wasteful. The voltage regulator method is found in most commercial electronics, from PC cards to clock radios, but is simple and cheap to implement and hence why.
Perhaps I didn't explain a lot of the overheating solving well.
Here's my present setup for my similar system to Seth's 30V runner. It's only a webcam pic and is grainy, but at least the webcam has a little focus wheel on the front, which my usual camera doesn't



By using a power transistor, D2641 (Datasheet: 2SD2641 datasheet pdf datenblatt - Sanken electric - Silicon NPN Triple Diffused Planar Transistor (Complement to type 2SB1685) ::: ALLDATASHEET ::: ) and 2x N45R203 diodes to the Base in series, I can run the tower with a 30V 500mA ex printer power supply all day.
The transistor did overheat at first, then I added 1 diode, which didn't really do much, but then added the other and as well as the output increasing markedly, the cooling was found.
It's in keeping with Dr. Stiffler's circuits, where the (normally) 2N2222A is protected in a similar way. His documentation describes testing and running at 12V and that's what put me on to the 'fix'
Other types of diode haven't done the same thing. 1N4148's didn't even see the tower fire up.
All components i've used came from junker spares, so unfortunately I don't have supply info for the transistor or those exact diodes. But, if you've got a box of circuitboards from PC monitors, power supplies and other larger mains driven equipment, just try different larger power diodes.

[sorveltaja]

Could the reason for a transistor overheating be the circuit itself?
Meaning, that it oscillates somewhat wildly, dictated only by L1 and L2, driving the transistor all the time at the maximum juice.

As far, as I understand, this basic exciter circuit doesn't seem to have any combination of components, that would allow the adjustment of its working frequency.

To make my point even more fuzzier, maybe some sort of 'chopping' of transistor's input or output? Like an additional, adjustable oscillator, that could be used to control the transistor? To give it time to take a breath between pulses, instead of saturating it continuously?

That chopping/pulsing could actually happen at a frequency way too high to hear, or see, when doing the basic testing, using cfl. Ranging from several hundred kilohertz, to several megahertz.

I just wonder, how that transistor-controlling oscillator(perhaps 555-based one?) could be integrated to the basic exciter circuit, in a simple way?

One thing leads to another one... so I must ask, what are the points in the circuit, to measure the L1's fundamental working frequency, while the circuit is running?

I have made several dozens of measurings, between almost every points on the circuit, that I can think of. Results are from few Khz, to Mhz range.

But, after all, I think there is a 'sweet spot', for every combination of L1 and L2.
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Mumbling aside, today I finally got myself to order some components:

BD131 x 2
MJE13007 x 2
2SC2655 x 2
2N3055 x 2
NE555 x 2

That shopping list(not the 555, for god's sake) is mostly based on different exciter circuits, that I've seen.

[NickZ]

Slider:
It seams that transistor heat is the limiting factor with these devices. Flathunter has also mentioned that he could only run is 30v Exciter for up to 5 minutes before having to disconnect it.
I'm going to try the bigger transistors, like the 2n3055, if I can get a hold of some, as it seams to be the only solution at this time. To use diodes to drop the input current to a more useable levels seams like a waste of resource to me. Capacitors like a 47000 mf on the positive rail will filter and do something similar, (even if only connected by one pole), but they will start to heat up also.
I've already tried two diodes, and a cap on the base, but that does not help much. The base circuit can be totally disconnected once the oscillators starts, and the circuit still heats up when using 12v. I don't even need to base circuit, as my Exciter will work even without it connected.
From what I understand that you are saying, the more turns on the primary (or L1) the less heat or eating up of the input current source, but, with less output as the result. Not really a solution, as output is diminished.
After watching a video made by LinxSteam he is showing the the 2n3055 will hold up to a 12v input voltage source. But, RS is out of stock on them here, though.


NickZ

[Slider2732]

Very different and very interesting sorveltaja...am enjoying reading of your experiments.
In my experience, the fewer the turns on the primary the more amp hungry, but the more the turns, the less output. Just a simple rule of thumb that seems to be going on with your circuit too. The 1 turn is producing great results with the plasma, but is eating that 9V battery !

Your 12V supply can be very useful, if you use good large diodes to knock down the input voltage. They work like a variac. An approximate 0.7V drop across each one will leave you with whatever voltage you wish, when connected to the Positive input and in series. For 5V, you'd need 10 diodes though, which may be unweildy. All is much easier with an adjustable power supply, like those 3V to 12V adapters.
A voltage regulator is another way, LM317T for adjustable or a 7809 for 9V, 7805 for 5V.

i do like those radical designs you come up with !

[sorveltaja]

After making numerous tests with crown- and sun coils, I must admit, that neither of them offer significant improvement over plain loop ones.

I simply got overly excited , when I found, that those forms also work with the circuit.

Anyways, from now on, please read my messages with precaution.
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Well, in the meantime, I have been experimenting, at first using one flat coil for L2, that I originally made for the conical coil. It didn't work with it, so I almost dumped it.

L1, that I use for testing, is the same spray can cap coil, as mentioned earlier.

One half of that L2:

Piece of thin (beer can) aluminum sheet, glued to cd-disk.

I ended up making an another one, similar to that previous:


So, L1, and pair of L2's formed a 'sandwich'. That pair of L2's are parallel with each other, when connected to the circuit.

Again, testing at 5V@200mA transformer. Plasma stream was there, also bright cfl. Nothing special.

Today, I bought a fresh 9V battery, just to see, does it make any difference to raise the voltage from 5V to 9V. It definitely did!

Cfl was as bright, as it usually is, but the plasma stream, it was way more 'violent', than I ever expected. I've seen similar things on Utube, where guys are using 20-30 Volts, to get similar results.

There is again one big if. That good, new 9V battery got very warm, during the testings, losing its capacity. Circuit's transistors were just lukewarm.

Conclusion: I have one really hungry circuit on my hands.

Next step? What I have available, is the 12V/2,5A PSU.

[sorveltaja]

While bending copper wire for the next crown coil, I ended up with form like this:


Sun coil perhaps?

It seems to work as well as crown coil, maybe even better, having bit wider working area, along the L1.

But. Using either of those coils have a serious drawback. They need a gap between them and the L1. If they get too close to L1, an arc is produced, which consumes the output needlessly. Wonder why this isn't the problem, when using plain loop formed L2.

So I took a piece of cardboard, and rolled it around L1, just to make sure, that there is this required gap. Tried two different thickness:


Be it thicker or thinner cardboard, both block the major amount of L1's radiation, resulting rather weak output.

After all, I think, that there is a workaround for that problem. Just need to find it.