Joule Thief

[SkyWatcher123]

Hi folks, here is a video showing the gutted cree bulb using 1.2 volt AA at 280 milliamps, around 350 milliwatts.
http://www.youtube.com/watch?v=cotfanu5F6I&feature=youtu.be
It is somewhat brighter in reality.
Going to try different things to make more efficient, maybe different cores.
Though it seems like a closed core, or at least like this flyback core, with a small gap is probably best to use.
Normally it is not audible, but with the magnets at back to hold to wall, it is slightly audible.
If the ferrite cores air gap is closed, the oscillator becomes much more audible and brightness only increases slightly.
So it seems a proper core gap is good to use.
peace love light
tyson

[Pirate88179]

Tyson:

Very well done.  I think it is great that you are using this circuit in your daily life, as I do.

I am in the process of testing various transistors in order to get the most from our AA batteries.  2 of the ones I will be testing should be able to take a battery down to about .22 volts.  I will keep you posted after they come in.  I will be testing them using the surplus camera flash boards so I will have a good baseline for the tests.

Bill

[crowclaw]

Just came across this utube Cree LED evaluation video which seemed quite interesting... might have a look into using these myself maybe. Regards Crow

[SkyWatcher123]

 Hi folks, made a couple modifications to the gutted cree 6 watt (40w equivalent) lamp.

Raised the input voltage to 3.8 volts, lithium ion pack salvaged. Added a 100 nanofarad non-polarized capacitor, salvaged from gutted cfl circuit. This capacitor is placed in series with the led bulb at the high voltage secondary coil. With a 1kohm base resistor and when using the secondary capacitor, the current draw is reduced almost by half. At 3.8 volts loaded input and 290 milliamps or around 1.1 watts, using the secondary capacitor, this puts out a very good amount of useful light. Without using the capacitor, the current draw is around 550 milliamps or around 2.1 watts and the led bulb appears half as bright. This capacitor in series with the secondary coil, seems to be a nice way to boost efficiency or is creating a better frequency match. peace love light tyson

[NickZ]

   SkyWatcher:
   Nice light output. How does it compare to the Cree bulb running on normal house current? One 1.1watt would also work well if connected to a small solar panel, for emergency light or for everyday use.

  I'm making a homemade solar panel now using 30 garden light cells all connected in parallel, plus three of the motion sensing light panels, which give about 10v each, all  connected in series with the garden light cells. I'll uploads some pics when I finish it.

   Do you remember back when Slayer used a 2.5 watt Ac led pyramid shaped bulb that was lit using the Lasersaber circuit, but only drew 28 mA at 12v, and 13mA at 6 volts?
He was using an E-core, and it also had very bright output, and at only 30 mA. 
10 of these gutted bulbs would only draw 300mA on 12v, or 150 mA on 6 volts, possibly.
http://www.youtube.com/watch?v=O6f8Etb5QJI
   He also has some newer videos out on his channel, you might want to check those also.

  You can use a light sensing diode from a garden light connected on a volt meter to test for the light output comparison. It works well and is very easy to do.

  I'm still lighting my bathroom and other rooms every night using my JT circuits.
Some led bulbs light better than others, but its hard to beat the flat tops for spreading the light all around. I'm also using the warm white flat tops, or the flat tops that have a darker golden light to them, that look almost like candle lights.

  Thanks for sharing with us, keep up the good work.

            NickZ