Lasersaber strikes again. A joule thief king ?

[Collapsingfield]

This file is based on a real coil on pot core. I have no symbol for MPSA18 and it is not easy to simulate all the parasitic effect. You can see how big effect have the 4 parasitic condenser  (including the coils) and the resistor on the base. This circuit is working on my desk by one LED with good intensity. I have measured the current on the LED by sensitive current probe and there is bidirectional current there.
Regards

[d3x0r]

Here is the Ltspice file:

can you include a screenshot?  alt-prtscreen and paste into paint?

[Collapsingfield]

LTSpice screencapture

[TinselKoala]

You are starting out at 9V or more ! And with a large-value resistor like 10 meghohms....  I'm just shaking my head and grinning. Of course you will get tiny glimmers that last a long time.  Of course you get deep spikes from the inductor.  Don't forget that a capacitor charged to, say, 10 volts has ONE HUNDRED times the energy of the same capacitor charged to 1 volt, since E=(CV²)/2.

I've never charged my version of this system to over 3 volts and mostly I run at _under one volt_ . I even installed a pushbutton bleeder so I can discharge the cap voltage down to where the thing is behaving in a more interesting manner, rather than just duplicating ordinary high-voltage JT waveforms like those shown above.

Here are some characteristic wave forms and pulse trains from my loopstick-LaserSaber system operating at under one volt. Note that this kind of waveform oscillation may be hard to show on a digital sampling oscilloscope.

http://www.youtube.com/watch?v=JaaWmXJIh_c


Bursts of oscillation in another low-voltage JT:

http://www.youtube.com/watch?v=mTOuUMsivWA

[TinselKoala]

For Windows: ScreenshotPilot is my favorite. For Linux: Use gnome-screenshot --interactive. For Macs: Don't you have some pr0n to watch or something?