Joule Thief

[SkyWatcher123]

Hi folks, Thought I'd share my conversion of this 12 led lantern that is normally powered by 4 D cell batteries, as shown in one of the pics, I'm using 1 AA and it lights to just about full brightness relative to using 4 D cells. Last night I used a dead AA non rechargeable and it stayed lit at same brightness for about 4 hours, so a fresh AA would last much longer. A rechargeable AA cell works well also, have yet to run duration test on AA rechargeable yet. Here are a few pics of it. 
peace love light
Tyson

[jeanna]

Hi pirate, thanks for the info about jeanna, do you happen to know or have a link to where i could read where she did that, thanks. ...
peace love light
Tyson

Hi Tyson,

I have been away. I am sorry I didn't respond earlier.
Bill is correct, I did try a smaller toroid and did prove it could light a cfl... AND, I am really just using those cfl's to prove the ability of the circuit, because leds are way better, meaning more light from less time and trouble and expensive toroids.

I made one that uses a 1 inch toroid, whose interior space was big enough that I could add a lot of turns.

Also, btw,
You will not get a fluro tube or cfl to light unless you use a robust transistor like the TIP31 or 3055. the 2N2222 or 2n3904 just cannot ramp the volts high enough. (The Tip's take more amps draw and this may be the reason.)

So, this pic was taken on dec 20 2009 and the post will be from around that time.
The details will be there.

I also have found that it is quite possible to choke the coil with too many turns; or with the secondary turns wound too close to the primary.
I used a piece of string and tied it like a loop of wire right next to the primary wires. This allowed me to wind the secondary to the end and not worry about touching the primary. It helped. Sometimes I needed 2 or 3 turns of the string to keep the secondary clear of the primary.

I hope this helps.

jeanna

edit...PS
Nice job with the lantern!

[Pirate88179]

Tyson:

Excellent conversion of the lantern with the JT circuit.  Isn't this fun?  I am always looking around to see what else can be converted.

Nice work.

Jeanna:

Nice to see you back.  We have missed you.  I knew you lit the floro with the small toroid I just could not find it here.  You should post a schematic of that if you can.  That is a powerful little toroid/circuit there.  I'll bet that can light many strings of leds too.

Bill

[jeanna]

...
You should post a schematic of that if you can.  That is a powerful little toroid/circuit there.  I'll bet that can light many strings of leds too.

Bill

Hi Bill,
Thanks,
Yes, it does drive a lot of leds.
I think the 2 elements that are most important are the high permeability of the toroid, which happens to be a toroid with enough room inside for plenty of turns,
and,
the TIP31 transistor.

This same toroid is the one I have used for many of the recent plant battery driven joule thief circuits and galvanic battery joule thief circuits.

There is nothing MORE magical about this particular circuit.
It is a joule thief circuit with secondary just like the jeanna's light, but with a smaller toroid.
From looking at the picture I don't even see a capacitor in parallel with the battery leads, which is something I usually need to add to light a fluro tube.

So, it might be a
TIP31 or TIP3055
a 1k pot
a toroid with 2T,9T and um... maybe 80T or um 160T secondary (but these numbers are specific to the toroid)
a magnet to help the tube start up
7w fl tube

I remember it took down a 750mAH AAA in about 3 hours, so it probably used about 150-200mA which is high but what those robust transistors can take.

I guess the point is that when using the joule thief circuit as a pulse generator to a secondary circuit as this style is, there is a lot that can be done.

----
On another joule thief subject,
I was in the camper over the weekend and the first ever jtc with secondary "build" I made (Newman's HOT is what I called it) stopped working. I checked the lithium AAA battery and it was down to 0.58v.

So,
1-that transistor was willing to work at a very low voltage. and
2- The battery lasted a really long time.
I think that was the first battery I had put in there when I decided to actually use it about 1 1/2 years ago.
I would guess that it was on from 20 minutes to 3 hours a day.

-----

And still another subject
The color thing.
I picked up a car light that has 5 yellow/orange leds in series.
I snapped 2 dead 9volt batteries together and turned this light on.
I taped it as a spot and directed it toward my lap.
It made a very good color when added to the 24 leds light I had also directed to my lap.
I was able to comfortably read for 3 hours with no eye fatigue.

I think this is interesting and I know Jim said it a few years ago, and I wanted to add my experience.

thank you,

jeanna

[SkyWatcher123]

Hi folks, Hi pirate, thanks for the compliments, the little modification turned out rather well. Though I can only guess that the 12 led lantern is wired in parallel/series, my guess is two sets of 6 leds in parallel and then these two parallel sets are placed in series, since 4 D cells make around 6 volts. I could make a new toroid with secondary to squeeze out a little more brightness, although it's plenty adequate in the standard JT emitter/collector output position. Hi jeanna, thanks for compliments and the valuable information about the 1" dia. toroid running the fuor. light, very much appreciated and all the work you and others have done. I have many other ideas sloshing around in mind about uses for these circuits and such, thanks to those sharing their experiments here, very grateful.
peace love light
Tyson