Akula eternal lantern 4

[TinselKoala]

@Itsu: the ringing on the end of your Drain trace is at the natural resonant frequency of your setup, probably. I'd like to see what happens if your drive frequency is the same as this ringing and your pulse duration shorter than 1/2 cycle of that frequency.

The change in frequency as the core is squeezed or relaxed is due to the changing in the effective inductance of the core, which of course changes the resonant frequency or frequencies that depend on it. I demonstrated this several times in my Akula videos.The gap is there in the core to prevent saturation at high power levels; it is possible that some of the effects you are seeing are a result of "tickling" the core on the edge of full saturation.

[d3x0r]

@TK scope issues; makes sense.
But; it's not the after-the off ringing of interest... it's the arbitrary spike in the middle.

[hartiberlin]

Yes, the spike in ths middle is really strange...
Maybe it is a delayed Barkhause jump effect by flipping the domains
inside the core ?

What kind of core is this ? What material ?

Istu, if you remove the core from the primary coil does this pulse still occur ?
Probably not, then it is core dependend !

Try to see, how you can increase the area below this pulse.
Does a bigger core help ?
It is probably related to the ON switching of the base pulse, so it takes around 60 mikrosecs to flip all the domains
inside the core and produce this pulse...

[hartiberlin]

Itsu,
Why does the yellow gate signal have these spikes at minute 3:50 when the signal is so short in length ?
Is your MOSFET defective then ? Where is the exact circuit diagram ?

[Void]

Itsu,
Why does the yellow gate signal have these spikes at minute 3:50 when the signal is so short in length ?
Is your MOSFET defective then ? Where is the exact circuit diagram ?

Akula was getting the exact same strange pulses on the collector and base.
It looks like these pulses may be what Akula is calling 'ferromagnetic resonance'.
See the attached screen capture from Akula's video. The same sort of strange pulses on the
base and collector that showed up in Itsu's video are in Akula's scope shots as well...

I just rewatched the English translation of Akula's video.
It seems those strange pulses are what Akula is saying are indicating 'ferromagnetic resonance'.
However it seems he says those liittle pulses on the collector by themselves do not give much power (the pulses are quite narrow, so that seems to make sense).
He then makes an adjustment to the pulse width and then gets the big exponentially rising pulses on the collector,
which it seems is where he is getting his extra energy to make the circuit self running.
All the best...