Notes
This circuit is a single transistor flyback (Joule Thief) circuit that features a third coil. With it, flash duration and brightness is much enhanced, without resorting to large value capacitors. The performance can be seen in the following Videos (on Youtube):http://www.youtube.com/watch?v=tgcYcPDbwNo
http://www.youtube.com/watch?v=wcHaE4rv64M
http://www.youtube.com/watch?v=2HLDPaO9oDM
The last is meant to upgrade a Solar Garden Light and demonstrates automated daylight power-off - with just an extra diode and resistor. You can also find more information about this and my other circuits here:
http://quantsuff.com