Akula eternal lantern 4

[itsu]

I think I have now figured out how to get those slow exponentially rising scope waveforms
that Akula was showing on his Collector. I am using a FET, but it seems to me that my
waveform on the Drain of my driver FET is now pretty close to what Akula was showing.
What do you think guys?

Hi Void,  please tell us how you did it,

Regards Itsu

[itsu]

@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.

Thanks TK,

i can find out the resonance frequency of the coil that way, but what we are trying to do is to find the ferro(magnetic)resonance of the ferrite of the used core in a way described by Akula.

But it should be good to know the resonance frequencies of the prim/sec coils as well to be sure we do not mix up.

Regards Itsu

[itsu]

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...

Good questions Stefan,  i can do some extra tests tonight.
No idea what material the core is made of though.
I have a smaller (half smaller) core which i can test.

No idea why the base starts ringing when the duty cycle gets shorter, the used transistor (MJE13005) seems ok.
The exact diagram (a part of the whole Akule diagram) is in post #65 (handdrawn):
http://www.overunity.com/14687/akula-eternal-lantern-4/msg412459/#msg412459

Regards Itsu

[itsu]

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...

He also mentions (translated tekst) to keep the frequency the same (256Hz) and indeed to "adjust the pulse".
Guess he manipulates with this pot/var cap. the duty cycle, but when i do that i do not see this "big exponentially rising pulses on the collector".

What i did was to decrease the duty cycle so the closing end of the base signal is around this strange pulse (60us) as this is
how i understand Akule was getting this "big exponentially rising pulses on the collector"

But not with me   

More tonight....  regards Itsu 

[Void]

I don't understand what happens here
http://youtu.be/DnuXqnTlJNM?t=9m25s
It doesn't appear to be a cut... he in increasing the voltage from 2.0V to 5.0V, and seems to click again to get 5.0V and then 10.0V but between the 5.0 and 5.0, the curve flattens out.  the negative basically totally disappears, and it becomes flat on the top... and then at 10:00 he's expanding the time, and there's no significant low dip...  and then by 10:15 he increases the voltage sensitivity again and the curve returns.... scope internal capacitance change?

Good observation. I have exactly the same sort of seeming strangeness going on right now as well on my scope.
The strangeness where the waveform goes from big curved waveforms to a flat waveform also happens for me when switching
between 2V/div and 5V/div on the vertical scale on the scope. This appears to possibly be some quirk of the way the oscilloscope works.
I have never encountered this weirdness when switching between 2V/div and 5 V/div previously however. I will have to check
out my scope further when I have the chance to make sure there is not something wrong with my scope, but Akula's scope
seems to have showed the same quirk when switching between 2V/div and 5V/div on this type of waveform...