Joule-Thief

This is a silly litle thing, that I enjoyed making quite a lot. "Joule-Thief" is a common name for an electric schematic that allows single 1.5V batteries to feed one or even more LEDs. Normally that wouldn't work because LEDs need a certain higher voltage to start lighting. The level needed varies depending on color. Red is the one that goes down most (1.6-2.0V). The other colors require even higher voltage levels. However, 1.5V is normally not enough!
This is where the "Joule-Thief" comes in.