How does a wind-up generator work?

....Just to clarify. I realize that a power spring can't produce electrical power. I just wondered if the mechanism truly winds up (like a wind-up toy) and then this mechanical energy is converted into electrical energy somehow.

Don

I have a FreePlay radio with both wind-up and solar power sources.

The wind-up mechanism on this radio works like a clock. You wind the spring and it drives a small DC generator (via a speed control mechanism) to power the radio for about 30 minutes.

Other "wind-up" radios may have NiCad/NiMH cells and either use the spring mechanism / DC generator to charge the batteries, or use a crank-driven DC generator to charge the batteries directly (not exactly "wind-up", but does use a hand-crank ;-)

John