Using the basic Solar charger developed here, we can build a very simple and effective reading light. Bright enough to light a small room, it is more than bright enough to work by, and a day's recharging is all it needs to provide over 2 hours of use.
A garden-variety solar cell (2-volt, 20mA) is all that's needed, and the entire circuit consists of ten basic components.
BC327 PNP transistor
BC337 NPN transistor
1N914 or 1N4148 Low power signal diode
100uF 6v capacitor
100uH inductor (A larger can-type is chosen for its lower internal resistance. Thanks to acmefixer for bringing this up!)
1 x Red LED 20mA
1 x White LED 100mA. A wide angle unit (90-degrees or more) is recommended here to avoid glare and hot-spots. I also chose the piranha style so I can get the 90-degree angle when I assembled it.