Akula eternal lantern 4

[itsu]

I am uploading a video now showing what the below screenshot shows, a stable peak in the collector signal during the active period of the transistor.
When pushing on the core halfs, this peak moves to the right.

Any idea what this could be?

60us = 16.6Khz

3V input in the circuit
250Hz DC pulse, amplitude 2V, duty cycle 0.4 - 4%
yellow = base signal
blue   = collector signal

Video here:  https://www.youtube.com/watch?v=XJMx_BsUnms&feature=youtu.be 


Regards Itsu

[itsu]

Here the same situation, now added the FG signal (purple) and the input current (green)
Current probe controller set to 200ma/div.

Regards itsu

[Void]

I am uploading a video now showing what the below screenshot shows, a stable peak in the collector signal during the active period of the transistor.
When pushing on the core halfs, this peak moves to the right.

That extra pulse when the base is still being pulsed does seem strange.
Off hand I can't think what would cause that extra pulse. Definitely interesting...

I have to run out to get a bunch of stuff done, but I will review what you guys are doing
in more detail later when I am back. d3x0r, I will check out that portion of the video
you mentioned later as well. Gotta run now...

[d3x0r]

I am uploading a video now showing what the below screenshot shows, a stable peak in the collector signal during the active period of the transistor.
When pushing on the core halfs, this peak moves to the right.

Any idea what this could be?

60us = 16.6Khz

3V input in the circuit
250Hz DC pulse, amplitude 2V, duty cycle 0.4 - 4%
yellow = base signal
blue   = collector signal

Video here:  https://www.youtube.com/watch?v=XJMx_BsUnms&feature=youtu.be 


Regards Itsu

Your core is bigger; longer flux path and I think maybe thicker (larger flux volume)
it (should/probably/couldbe) a saturation of the core... remembering back it's the joule thief/kacher circuits I was playing with that seemed to lead the base falloff... such that once the core saturates, it seems to avalanche all the flux back out... others have strong opinions this isn't the cause/effect of a joule theif... and since I've seen lots of operating modes... but I digress...
so a wider gap should shorten the time to the spike ( can you pull on the halves to separate them a little more?)
The melnichenko cores had a very wide gap (a range in millimeters).
the translation said the time was highly dependent on the core.


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I really like to see that the base didn't dip goes to reinforce that it's not the base/gate triggering the action.

[TinselKoala]

I have not fully analyzed the situation, but I do recall that some persistent OU claims of LTseung had to do with just such a negative excursion in some measurements he made on his Atten scope and that was apparently duplicated on some other Atten scopes. This was finally tracked down to an unadjustable DC offset error in the scopes themselves, that showed up on the most sensitive attenuation settings.
I'm not saying that this is the problem here, but it could very well be, and you folks who are using Atten scopes (and all scopes for that matter) should carefully check your displays for inaccurate voltage levels and polarities at very sensitive settings and small voltage values.