Kapanadze Cousin - DALLY FREE ENERGY

[Dog-One]

Why "differential" and not just "current transformer" ?

The author says it is wound bifilar, which immediately made me think of your loss-less clamps.

Apparently it filters high-frequency switching noise and can be made by-hand unlike typical current sense transformers that have thousands of winds with very tiny wire.


Whether it works better than an OEM current sense transformer remains to be tried and tested.

[itsu]

Minus the forward voltage drops of the PS diodes.
Yes, but I doubt the MOSFETs are ringing with the inductance of the primary winding, because this inductance is simply too large to yield such high frequency. 
Pls use the formula C = 1/(39.478 * f² * L) to calculate how low of a capacitance you'd need to have, in order to get a 14MHz LC resonance frequency (f) with your primary inductance (L).

Also, a time-domain scopeshot of the drain waveform would be useful to identify the ringing stage.


Pls try to connect a parallel 47pF cap to the gate and/or drain of the MOSFET in order to locate where that LC parasitic is exactly.  Look for downward frequency shift.


It could be related to the placement of the air gap under the windings or the capacitance of the winding but doubtfully related to the inductance of the primary winding which is simply too large to resonate at this frequency with realistic capacitances.
First of all, these additional peaks cannot be related to the yoke just changing its inductance, because such change would only cause a frequency shift of the existing peak.

New peaks cannot appear due to a change of inductance, but they can appear due to any nonlinearities introduced, such as ferrimagnetic saturation^* ...and other effects.
It is not so chaotic:

First of all, the peaks at 18.833MHz, 28.250MHz, 37.6666MHz, 47.08333MHz are all consecutive harmonics of the 9.416MHz peak.
That leaves only the small peak at 35.25MHz as the odd one.

The 14MHz is also unrelated to any other peaks, but notice, that this 14MHz peak does not belong to the group of peaks that was caused by the permanent magnets.


^{* It is unlikely, that these relatively small and weak ceramic magnets could saturate such a large yoke core.}

Cross checking the 14MHz peak on the spectrum analyzer with the drain signal confirms that it is caused by the ringing of the MOSFETs.
First screenshot is from the spectrum analyzer, seconds screenshot a zoomed in picture of the ringing when a MOSFET closes.


Paralleling a 47pF capacitor to gate / source does not show any difference in this ringing, paralleling it to the drain / source shows a minor frequency decrease of about 200Khz .


In the test with the 4 stacked ceramic magnets, i noticed that when the magnets are attached to the yoke midway a primary, that that primary MOSFET gets hotter (due to the harmonic peaks production).
The other MOSFET stays the same in temperature.  When putting the magnets midway the other primary, then the other MOSFET gets hotter 

So it seems that the magnets are causing only 1 primary / yoke half* / MOSFET to behave differently (chaotic)

(* With "yoke half" i do NOT mean the physical half but rather the half which has a primary.  Each primary has a yoke split halfway.)

Itsu 

[NickZ]

  Itsu and All:
  As you may know, I've been using the snake egg shaped magnetite magnets in the yoke core.  Sometimes I use three of them, for better tuning and gain. As the more magnets used, the higher is the output, and brighter bulbs, also. With three magnets the magnetics of the yoke's output, can be fine tuned. This does not just apply to the Mazilli crt.  Since the yoke running frequency, and the wave forms shape can therefore also be tuned and adjusted.
The main point is that increased gain is noticed at the output when using the magnets, and not just by a little bit. And, it works also in conjunction with the ferrite pieces that I use inside of the grenade former tube, and ferrite pieces inside of the Kacher former.  They can all be tuned by moving them around, for best output. 
   If ferrite, and magnetite is not used to aid in the tuning efforts,  the actual output noticed at the bulbs, will be noticeably lower.

[T-1000]

Hi all,

Here is some update on Tesla coil driver. I made corrections to Oleg's original circuit and ended up with this circuit:
http://i.imgur.com/426K40t.png

It was tested with my small Tesla coil and was giving lots of EMP to surrounding electronics...

Cheers!

[Void]

Cross checking the 14MHz peak on the spectrum analyzer with the drain signal confirms that it is caused by the ringing of the MOSFETs.

Hi Itsu. Great that you were able to figure out what was causing that.
It seems you have your PWM driver sorted out and working very well now...