Joule Thief

[SkyWatcher123]

Hi totoalas, hooked up diode both ways as you suggested, did not see any change in light output.
Though i hooked it from top of coil to either secondary leg.
Is it possible you meant from the collector of transistor to either secondary leg.
So what do you think about the series secondary capacitor and its effect on this circuit, does my idea sound like that's what might be happening to benefit this circuit.
peace love light
tyson

[totoalas]

Hi totoalas, hooked up diode both ways as you suggested, did not see any change in light output.
Though i hooked it from top of coil to either secondary leg.
Is it possible you meant from the collector of transistor to either secondary leg.
So what do you think about the series secondary capacitor and its effect on this circuit, does my idea sound like that's what might be happening to benefit this circuit.
peace love light
tyson

Yes ur right i used collector   
About the cap in series  have u heard of parallel and sries resonance  in an rlc  circuit  on parallel  and off series  resonance with caps  ?? Id better test ur ckt as well

[Pirate88179]

Hey Bill

Can you use a JT to charge say a 1uf or 10 uf cap to 100v pretty quickly?

Thanks

Mags

Mags:

I would think you could do that and it should work pretty well.  The caps seem to like those high voltage spikes, at least the super caps that I have used seem to.  Not much amp output from the JT mostly voltage but they should still charge up pretty fast I would think.  Take the flash circuits for example, as they charge that large 300 volt cap in just a few seconds.


TK:

That is a great circuit!  Are those inductors available from a supplier somewhere?  I don't recall seeing any of those in the surplus catalogs...goldmine,allelectronics, BG micro, etc.  That is higher voltage than I can get from any of my modified flash circuits.  Have you tried a TIP3055 in that configuration?

Bill

[totoalas]

http://www.youtube.com/watch?v=VN1HHrbFDac

[TinselKoala]

@Pirate: I replied to your comment on the video. I don't know about suppliers, I got it from a TV chassis and modified it by adding the outer 30-turn winding of #22. It was originally encased in a white plastic box housing, that might have a part number on it, I'll try to find it but don't hold your breath, this place is packed with junk right now. Also, not all 2n3055s are created equal; I have a few that are 'good' but won't make this kind of voltage. No, I don't think I've tried a TIP or MJE 3055 in this particular circuit, but I think I have one in the box somewhere so I may sub it in just to see.
Thanks for your interest! I think that one reason this one works is the "secondary" with 300 turns is tightly wound on the good ferrite, and then the 30 turns I put on are on the outside of that, also tight and neat. I potted it in epoxy but that's probably not really necessary... but you never can tell, it might improve the Q.
I realize now that I can hear it oscillating in the video, so there is still something loose in there. The best tuning of the pot is pretty narrow too, so I do recommend the 10-turn trimpot. It may require a bit of retuning if the supply voltage is different, which is why I didn't use a fixed resistor.
I use the 1n4002 diode in there even though the spikes exceed the voltage rating. Again, I don't know if this is important or not. If you find out, let me know!

Thanks for taking a look!
--TK

ETA: Here's the inductor after my added winding and before I potted it: