Joule Thief

[jadaro2600]

@ jadaro2600

I am just guessing, but maybe your circuit "jtc_res_2" will oscillate without the upper inductor. It looks like you may have made  a type of relaxation oscillator. But the upper inductor is needed to light the LED since that is what produces the voltage spike.

You come up with very interesting circuits.

It may work like this. The capacitor charges up through the resistor until the voltage is high enough to turn on the transistor. When the transistor turns on it looks like a short to ground and will drain the voltage from the capacitor through the resistor. When the capacitor voltage gets low enough the transistor will turn off again.

Thank you.  It will only light one LED, other can be put in parallel, the light it emits is very low, not too low though.  It was using 1.2mA a minute ago, and taking a votlage reading, a capacitor charges to 3.8v.

I think that the operation is somewhat strange, it has two paths, wihc can essentially be open at the same time via the upper inductor, but 'relaxation' occurs, as you say, due to the capacitor charging and discharging.

the main capacitor seems to have a charge on it of 0.58v ...  the capacitor is labeled 221

I tired inductors of larger value and they don't seems to work - only very low inductances are working.  These were mismatched pairs however ...

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It's snowing here for the first time in 8 years ...  if it sticks, it will be the first time in 18 years.
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Edit: ..correction, this device only seems to work when the inductors are matched inductance.  I have two larger inductors, but they seem to be producing the same effects.

I'll be trying to tweak the capacitor to see what the results are.  The device seems to reach a resonance at a low level of output voltages in this configuration.

[xee2]

@ jadaro2600

See my edit. If you can get it working without the lower inductor then I think this is what is happening.

[jadaro2600]

@ jadaro2600

See my edit. If you can get it working without the lower inductor then I think this is what is happening.

I'll try this approach, perhaps I can use a small resistor instead; I was hinting at this with the design, but things seems to be sensitive in this setup.

[xee2]

@ jadaro2600

If you need the lower inductor then you probably have an LC oscillator. But this should not work without feedback from the other inductor. With feedback it would be similar to slayer007 sec circuit.

[jadaro2600]

I just discovered a very unusual effect.

Using matched axial lead inductors in the configuration below - by bring a magnet near one, I am able to turn the oscillations OFF, by bringing it close to another, I am able to brighten the LED output OR turn it off using magnetic orientation...

Some help in figuring this out would be appreciated...

I have rearranged the circuit, So I post below the schematic, and perhaps I'll have a video of the effects soon.  I am not much of a narrator, so I may not be speaking in it.

I'll be testing some inductors which have an obvious field configuration to them so that I know how the magnet is oriented relative to the coil.

Edit: update;  I do have some other inductors and tested them, the light output ceased when apply a magnetic field axially with the windings. of the base inductor / capacitor array... it had little effect on it with the magnet at perpendicular.

Additionally, placing the magnet axially on the collector inductor had the same effect ( light stopped appearing ), while placing it at perpendicular only minimally increased output.  This may simply have the effect of increasing the inductance on the collector inductor.

With the larger coils, orientation at 90 degrees causes a shutoff, strangely though, this happens when one is in the vertical position and seems irrelevant elsewhere ( which I find odd, it's almost as if it's interacting with the capacitors ).

I'll try to upload a video and post the link here - i don't feel like messing with youtube at the moment.

Here is that video w/ diagram in zip file: http://www.overunity.com/index.php?action=downloads;sa=view;down=370