The Joule Thief. I found this device on accident. I was searching for a WORKING decision maker and found this on accident. It can power many LEDs.

The inevitable: I make an instructable on: the Joule Thief.

This is a great circuit to teach children about electronics especially inductors and coiling considerind it contains so few parts and is so easy to make...

Let's get started.

To get us started, I have a video.

By the way: I had forgotten to put the arrows for the LEDs...sorry.

Step 1: Materials, Materials, Materials

You will Need:

3 ultrabright white LEDS
1 "dead" battery (with 1 volt left.)
1 2N3904 Transistor
1 jumper
1 handmade inductor or two pre-made.
1 Solderless breadboard

Step 2: The Inductor.

Which one should I pick???There are thousands!

Well, I think you'll stick to the one in the second picture.

The 4th photo and beyond is courtesy of Evil Mad Scientist Labs. When I was making mine, I didn't realize that I had used enameled wire instead of colored CAT cable wire.

Step 3: The Circuitry.

Once again, I thank Evil Mad Scientist Labs.

Anyways, I omitted the 1k resistor. I don't know what it does but for now, i just know that I can power more LEDs. It might have something to do with current supply. If you know, please leave a comment.

So, build according to the schematic. Just remember, the two tabs that are tied together are the same tabs that connect to the positive of the "dead" battery.

Step 4: Fin.

Once you have built it, sit back, relax and enjoy the show that these LEDs put on.

One "dead" battery will give you about 65-70 hours of constant use. If you only use it at night then you would have a lot more time.

As always...if you experience any problems leave a comment and I will try my best to help you.

If you did make it successfully well then...leave a comment saying you made it successfully!

Step 5: Troubleshooting.

The problem with this circuit is that troubleshooting is virtually impossible unless you have a scope...

When I used a multimeter, it showed 1.2 volts going into the white, 3.6v LED. (The battery was 1.3v.)

A scope would show you the pulses though...

Well, there's not much I can explain about this circuit...but I'll do my best if you have any questions.