Joulethief1
Alex writes –

“Here’s the schematic, it works as a voltage converter to draw just 20mA from a 1.5V cell to light that white LED. The term ‘Joule Thief’ is used because the circuit will work from a cell which would otherwise be considered spent. I found that if the batteries in my Gamecube Wavebird controller stopped working, the same “spent” batteries will quite happily run this torch for a couple of weeks. Continuously.”Link.

Related:

  • HOW TO – Make a Joule thief – Link.