My joule thief in cfl.

[gregted]

Hey all,
Watched a youtube vid a while ago on the joule thief made from a disposable camera and decided to have a go.

I made mine to fit inside the original housing on the cfl and attached a switch to the bottom for a completely stand alone bulb.

Really happy with the build and have decide to add another feature to the project.

I bought a solar powered/charged torch from super cheap autos and this seems to charge at 2.13 volts from the light produced by the cfl running from 2 1.2volt aaa 1800mah batteries.

Next is to connect the charger up to the batteries in the cfl and see how long they last.

I've got a couple of questions regarding run time on this cfl.

My cfl seems to use 220 milliamps and I would like to know how long this cfl would light on these batteries without my charger connected.

If someone could tell me how to work this out, I would be very grateful.

Is it as simple as an 1800mah battery would run a circuit at 1800millamps for 1 hour.

This would mean my cfl drawing 220 milliamps from a 1800 milliamp battery would last 1800\220=8.18. So 8 hours use.

Have attached pics to help explain my project.

I have also taken pics after removing the unnecessary parts from my camera board if anyone wants to know how to do this. I found this better than trying to un-solder the sensitive parts and try to resolder them onto another board.

[Pirate88179]

Hello:

That is a very nice self-contained build you have there.  Good work.

As far as I know, you are correct on the mA's calculations.  The only thing is that in real life, it will be somewhat less as, depending upon the transistor used in your camera board, it will stop switching at a certain level...maybe .65-.85 volts?  But, this gives you a good idea and you can then test yourself.

If you can get them in your area, I suggest trying the Cree 60 watt equivalent LED bulb, or a Lights Of America LED bulb.  The Lights of America bulb can be used as it is but the Cree has to be gutted.  You will get much more light out of either one of these compared to your CFL.  It will last longer too.  I can easily get 20 hours of light from a single AA battery on the LOA bulbs and about 12-14 hours from the Cree.

You did a good job trimming the camera board down to be able to fit in the base.  Your light is something you should be proud of and most people will not understand how the heck it works, ha ha.

Very nice work.

Bill

[gregted]

Hi Bill,

Great name. My middle name is William and was called Bill by my dad for years. He's the one that got me tinkering. He was always pulling things apart and he was an optical mechanic during the war.

Thanks for the kind comments. I am really happy with this build and will build more for some mates. The wow factor is a great reaction to witness. The funny thing is unless you know something about electronics, running a 240 bulb from 2 AAA batteries is not such a big deal. Some have thought it is just another trick led bulb.

The transistor on the board is a D965.

I have included some photos of the completed gutted board if anyone else wants to go that way. I tried to remove the components from another camera board but couldn't get them to work on a strip board so decided to leave the sensitive parts lie and bridge the needed tracks on the underside.

White is High voltage out, black is negative input, orange is positive input and blue is high voltage out.

The next step is making 2 identical setups and running them both from 2 AAA bulbs of the same voltage and running 1 with the solar torch re-charging from the light produced to see how long it lasts compared to the other 1 with no re-charge.

Greg

[crowclaw]

Hi just thought I'd re_ post this image I posted here a few years back. To switch on I used used a thin
strand of copper wire concealed around my fingers. The wire then shorts the screw base and it's pip
acting as the switch. The outer appearance of the lamp thus appears to be untouched! Nice party trick He He
Still have this somewhere in my collection of gadgets.

Sorry, couldn't get the image back. Will try again.

[crowclaw]

I still seem to have trouble reproducing this image!! as I did in 2009.
If anybody can rescue this again this was the posting containing the image cheers:  Re: Jule Thief  « Reply #11001 on: December 22, 2009, 10:06:28 PM »