If you’re going camping this summer, or just want a cheap emergency lantern powered by a pair of AA batteries, you probably can’t do much better than [rimstar]’s Joule thief compact florescent lantern.
The circuit for [rimstar]’s battery powered CFL bulb is a Joule thief. While these circuits are usually used as a demonstration to get every last bit of energy out of a battery with a LED, [rimstar] upgraded everything with a better transformer and a power transistor to light up a CFL bulb.
What’s really interesting about this build is it provides a use for blown compact fluorescent bulbs. The normal failure mode of these light bulbs is usually the electronics going bad, not the tube. By replacing the electronics with a homemade circuit, it’s an easy way to reuse these broken bulbs.