I was in the grocery store yesterday and they had some closeout Christmas stuff, so I bought a toy light and charger for $1. Taking it apart it has two or so square inches of solar panel, a 1.2v NiCad battery, an LED, a resistor (I can't read the color bands, and I'm too lazy to take it out of circuit to measure it), and a potted 4 lead IC. A poor schematic (well, diagram) is below.
When the solar cell receives enough light, the battery charges and the LED is off. When there is insufficient light, the LED turns on.
Knowing nothing about charging NiCad batteries, I was wondering how clever the potted IC is likely to be. Not that it matters, and I don't plan on doing anything with it - I'm just curious.
Thanks in advance.