Joule Thief

Pirate88179 · July 26, 2009, 03:21:22 AM

Quote from: sm0ky2 on July 26, 2009, 03:07:06 AM
They couldn't have given this device a better name.

because i feel like a Stole something !!!!

Smokey:

Nice work! If I counted right that's 19 leds from a single AA battery....correct? Well, your not supposed to be able to do that so, this is where the real fun starts. You can show your friends and try to get them to light just ONE led from an AA and they can't. Yes, Joule Thief is an excellent name.

As Jeanna will tell you....the difference in led brightness does not seem to diminish much with 1 or 2 leds, or 10 or 20.

Bill

sm0ky2 · July 26, 2009, 03:35:56 AM

Quote from: xee2 on July 26, 2009, 02:53:25 AM
@ sm0ky2

Most transistors will work in JT with a 0.60 volt battery. Try putting a large capacitor in parallel with your EB. Germanium transistors will work down to battery voltages of 0.3 volts. I have suggested using them but no one seeems to have posted much data about any results. Gadgetmall has apparently gotten good results with them.

the cap was my first instinct, but the 3904 isnt wanting to turn on with 0.6v neither is the 3906. i believe these are the smallest that i have available at the moment.

sm0ky2 · July 26, 2009, 03:37:00 AM

Quote from: Pirate88179 on July 26, 2009, 03:21:22 AM
Smokey:

Nice work! If I counted right that's 19 leds from a single AA battery....correct? Well, your not supposed to be able to do that so, this is where the real fun starts. You can show your friends and try to get them to light just ONE led from an AA and they can't. Yes, Joule Thief is an excellent name.

As Jeanna will tell you....the difference in led brightness does not seem to diminish much with 1 or 2 leds, or 10 or 20.

Bill

thanks! we may yet redefine electrical theory with this thing.

Pirate88179 · July 26, 2009, 03:51:47 AM

Quote from: sm0ky2 on July 26, 2009, 03:37:00 AM
thanks! we may yet redefine electrical theory with this thing.

Now you are talking! Let's do it.

Bill

xee2 · July 26, 2009, 04:29:28 AM

Quote from: sm0ky2 on July 26, 2009, 03:35:56 AM
the cap was my first instinct, but the 3904 isnt wanting to turn on with 0.6v neither is the 3906. i believe these are the smallest that i have available at the moment.

I have tested the 2N3055 down to 0.55 volt battery. But, the toroid and numbers of turns may make a difference also. I think a cap in parallel with battery is good idea at these low voltages.