Joule Thief

[crowclaw]

@freepow, The circuit works as follows: TR1 adjust the point at which the green Led turns on (cap fully charged point). Start adjustment at minimum and gradually increase the pott until led is bright ( don't exceed 20mA) 16mA is ideal. At this setting TR2 should conduct and act as a dummy load for your solar panel, thus preventing over charge. Circuit should operate at 2.9volts_3volts. The capacitor is included to prevent set limit instability... you can experiment with some of the values as indicated. Transistors can be similar types_ TR2 must be capable of handling at least 300mA. All resistors can be 1/4 watt preferably 1%. TR2's collector resistor minimum 1 watt. 5% _ 10% Note your red will stand a forward current of around 20mA... depending on your cap's charge state you must take this into account, as it could be damaged. If you need a higher charge rate, substitute for a schottky diode rated at 1 amp (they have a low forward voltage drop_typically 0.3 volts)  Kind regards Merv

[stprue]

@Pirate/all

Did anyone know about this?

http://www.youtube.com/watch?v=tSxc5jbaAIU&feature=related

[freepow]

   Thanks very much Crowclaw !


      Can I have a solar cell with output of 70+ mA  and have the red LED working as a charge light and still
      have the green LED turn on when Cap is charged full ??

[Pirate88179]

I have made the fuji joule thief circuit to light up a CFL and LED’s but for some reason mine is not as powerful as others. For example there is a guy on youtube by the name of Lasersaber who built one of these according to piratelabs, just like how I built mine, who is able to get great results.Laser saber video…

http://www.youtube.com/watch?v=sFpzkyP6DCU

I have one of those cone shaped LED bulbs like lasersaber has but mine only lights 3 of the many LED’s while all of his light up and not only that they also light up about 100 or so more. I also saw that piratelabs had his light up 400 LEDs! I don’t know what I did wrong because I can only light up 3 of my LED’s in my cone shaped bulb.

I removed the big capacitor. Cut the end of the diode and solder my wire to the other end and a wire to the negative and that connected to the CFlL or LED. Then I tried piratelabs way of soldering those to connections in the middle of board and use that along with the diode connection to power a CFL And LED but still the same results, only able to power 3 LED’s. I also add the on/switch to it just like the one piratelabs have. I don’t get it what am I doing wrong? Can anyone help me? Thanks!

Ibpointless:

I am not sure what could be wrong, it sounds as if you did the mod correctly.  I had a lot of trouble lighting a cfl with any of my Fuji's for a while and when I finally got it to light, it was not all that bright.  I did much better with the floro tubes and the leds.

Can you post for us a good close-up photo or two of your Fuji board?  Maybe one of us here can see something wrong?  We will try to help you as much as we can.


Stprue:

Yes, I remember seeing that video a while back.  I never tried what he was demonstrating though.

Bill

[freepow]