I don’t like the term Joule Thief so I renamed it a “Watt Winger.” The teaching version of the Joule Thief circuit uses transistors and a homemade transformer.

We can use it to squeeze the life out of our drained batteries. Bottom-line, this circuit makes LEDs glow even at low voltages. Let's get started! Hummm, you probably encountered a joule thief before.

Joule thief are small, fun circuits which exploit a few characteristics of electronics and LEDs in order to “steal” virtually all of the energy stored in a battery. They can operate at … ...

Related: HOW TO: Make a stunning wooden table with glow-in-the-dark resin infill If you want a voltage booster, connect a Joule Thief circuit to the DC output of the CPU fan.

After boot, the micro takes control of the joule thief circuit and milks it whenever the voltage falls below 3.2 V. This tree may be small in stature, but it’s feature-rich.