# The simple joule thief using AVR microcontrollers

The Joule Thief is such an easy and simple device, but what it does is amazing. It can use a battery that is not usable in any other electronic device and give it life again. It can even take a battery that won’t even power a basic LED by itself when it is brand new (1.5 volt AA) and amplify the power so that it can.
This “Joule Thief” circuit, using a battery that won’t work in any other device, can power a blue or white LED for approximately 8 days straight before it stops working. It could probably power a red LED for at least 10-12 days. You could also use it to power a microcontroller (such as an AVR or PIC MCU).
This is an entry in the LED Contest with Elemental LED and the Hurricane Lasers contest, so if you like it, vote!

## Step: 1 Why is it called a Joule Thief?

The reason the Joule Thief is called what it is is because of what it does. (That sentence was confusing) (:
Basically, what the Joule Thief does is it “steals” every last Joule of energy from your batteries. The explanation of what a joule is can be found on the Wikipedia page here. The quickest explanation I can think of is that a Joule is a form of energy that, in the way we use it, can be used to power electrical devices. I won’t go into any more detail here because it gets very complicated.

## Step: 2 Parts list

To make this “Joule Thief”, you will need:
1x 470uH inductor (looks like a fat resistor)
1x 2.2K resistor
2x 1K resistor
2x basic NPN transistor (2N3904, 2N2222, 2N4401, etc.)
1x 1000pf (same thing as 1nf or 0.001uf) ceramic capacitor
1x AA battery + holder (or any other 1.5 volt battery)
As many LEDs as your heart desires.

## Step: 3 Make it on a breadboard!

It is super simple to make on a breadboard because it has such a low parts count. Look at the schematic to figure it out.
For more detail: The simple joule thief using AVR microcontrollers