Contained in this video is another way of finding the resonant frequency of a stand-alone coil using the VCO section of the CD4046BE PLL chip.
http://www.youtube.com/watch?v=XMQkCW5vZVc
When both LEDs are at max brightness the coil is being oscillated at its resonant frequency.

    TK:
   Ok, thanks for the reply.
   It looks like the magnet in the yoke can change the frequency, especially to lower it, but the voltage I can only raise a little bit, yet the bulbs do brighten up.  Same thing with using ferite inside the Kacher former.  Those are my tuning pots, for now, along with ferite in the grenade former. For that to work, I need to be close to the right frequencies to begin with.

   Itsu, Hoppy: Good to hear that you're both checking out the Akula way of finding the grenades best resonant frequency.
  Have you tried to connect the earth ground line to the end of the grenade, like is shown, even a short one to see if there is any
influence the in flatline readings. 
   Should I wait to see what you guys can come up with, before borrowing a SG?

  BTW: What was the Ruslan way. No scope, no signal generator. Remember?
Now he has everything, but doesn't know just how to use it all, yet. Or doesn't need, to as he says.

  Is anybody going to try to make the PCB and build up the latest version of the Ruslan push-pull and Kacher circuits?

Nick,

well, if step 1 in Akula's methode of measuring a coils resonance is already not working, i think it is of no use to continue with the next steps (grounding one side etc.).


Its not sure if this latest version of the Ruslan push-pull and Kacher circuits are really being used by Ruslan.
They are "designed by ALLEGGA", and we have no info on him (relationship to Ruslan?).
But anyone who is able to make a PCB from that PCB layout, be my guest.

Regards Itsu

Hi Jeg,

yes, like a "grid dip meter".
But then Akula should have searched for minimum amplitude, instead he seems to hunt for maximum amplitude to find the resonance.


Itsu

Thanks TK,

My cap coil is actually two aluminium foils forming capacitor on the 40mm tube - but connected as a Tesla bi-fillar coil. In other words it is Tesla bi-fillar  coil made of aluminium foils (around 7 turns).

You are looking resonance in wrong ranges. You should look between 40-60Mhz. I could say you a narrower approximate but i need the length of your wire including the cables that you use to connect your coil to the rest of the circuit. Also, if your winding turns are the one next to the other or with gaps, it matters.
 
An easy way to find your frequencies if you haven't any hf fg, is to pass through your coil a square pulse which you have to vary. At certain frequencies you will notice rise of the high frequency ripple wich is imposed to the pulse. Write down all the rising frequencies after you sweep your coil and you will see that all are related between each other in a harmonic way. From this you can estimate your res freq. 

I am still wondering why PWM is a desired strategy here at all. The TL494 is a very popular chip among solid-state Tesla coil builders even today but it's seldom used as a PWM driver; rather, people use it to make the basic squarewave pulse at the desired resonant frequency, to drive a mosfet bridge ( with a proper gate driver between) which feeds the TC primary. My TinselKoil II uses this strategy very effectively. The 494 isn't able to meet the high frequency demands of a small TC though, but the genuine Texas Instruments TL494 can be made to work at much higher frequencies than it is "officially" rated for.
 
The SG3525 is a PWM motor controller chip, I have Arduino shields that use that chip to directly drive small motors. I even have a couple of the Velleman K8004 PWM motor driver kits that use this chip; in this service the frequency is generally chosen to match the particular motor you are driving, and then the pulse width is used to control the speed (average power) of the motor.

By far the best strategy for driving resonant circuits (imho) is to use a Phase Locked Loop like the CD4046BE as the basic oscillator, with feedback so that the oscillator "locks in" to the actual resonant frequency, or some multiple or divisor of it as determined by other logic chips, so that the system remains in the resonant state as the actual resonant frequency changes with changing loads, environments, etc. With the appropriate high current, fast, mosfet gate driver chips between the PLL and the mosfets of course. This is the strategy used in my TinselKoil IX (but with discrete transistor mosfet driver rather than a driver chip.)

Perhaps you meant "pf" not "nf" ? At the frequencies you are talking about here, it will still be better to use a mosfet driver after the pulse generator, like TC4420 for example, or a driver stage of discrete transistors, which can provide several amps of current to the mosfet Gate for clean switching.

hi TinselKoala,

The PLL circuit does produce result which surpass the PWM generator circuit.

But there is one small problem in one of kapanadze experiment while using PWM set at around 30% duty set at around 28khz revealed that the kapanadze coil was oscillating at 1/2 the frequency.

Yes it's approx 14.4khz.But the input signal is running at twice the frequency at approx 28khz.

Duty cycle seems to play a part.

If coil is force fed with 49% duty which also means the kapanadze coil got no chance to self oscillate/resonate.


I also tried to use the frequency div by 2 between pin 3 and 4 of pll it was not able to recreate what i was looking for.

Maybe the output of PLL is fed to TL494 clk in which then split the signal.This part i have not tried yet since i am lacking time to be involved in few projects in one go.
I do wish i got 2 of me to do multi tasking.

Using rectified mains voltage from sine-wave inverter revealed that merely using less than 10% duty is required.
Many members still don't get it why Akula was using snubber to protect the 600volts IGBT's.
Snubber isn't required if we are fooling around with battery voltage like 12volts...30volts.

Yes i forgot many were sticking to Ruslan the replicator but with insufficient knowledge in circuit/pcb board fabrication.
People do seem to believe in someone whom DON'T create his own circuit.



Using PLL with suitable i/c to split signal still do not allow anyone to meddle with duty cycle in the end.

--------------------------------

I am lacking time since i am doing R&D for a another project which is on the verge of completion before testing stage.

  Magpwr:
  So, that is the direction that you would like me to go??? While you are showing NO results from the circuits that you are recommending to use.
  I would be more concerned about your own goals and achievements, without needing to yell in our ears with your red letters.
  I am working on this in my own way.  But, if you'd like to recommend something else, it helps to show how well it works for you, first. So far you've shown no OU, and no self running results from all your "new tricks". Therefor, your recommendations aren't very convincing or motivating, to me.

  As I've already mentioned, I'm still looking for a commercially available driver circuits for both the Kacher, as well as the Yoke/grenade circuits.  So, please get off my back... as I don't need your negative comments, trying to make me look like an idiot.

  Yea, tooooooo bad!  And it's too bad you're such a brat.

  Jeg:  This is the Akula video showing the starting of the procedure for finding the grenade's output coil resonance.
  If you guys aren't seeing anything but a flat line, there may be something wrong there. We know that without that reading, there is little chance of the Kacher or inductor coils being able of pulsing it, at it's best resonant frequency, or its harmonics.

  EDIT:  Here's the video:
    https://www.youtube.com/watch?v=fp3sed_eli0

magpwr and NickZ

Messing with each other won't do any good. In the end it does not matter which electronics you use for creating same signals which follow same conditions for resonance and managing sharp pulses on top of sine wave. As long as you are able to follow what was said and shown by multiple people with creating same conditions it is all OK.
The backgrout EE/RF knowledge required can be learned if you really struggling with bits in it and that only takes time for understanding how two waves interact with each other and how signals need to mix and match in grenade coil..

Cheers!