This is my entry for the 555 contest. I didn’t have much time to make something so the entry isn’t much.
This design is a fan controller. The base of it is a simple pwm circuit with the 555 timer. The problem with fan’s is that they don’t start at low voltages. So I added a capacitor (C2) to give it a little voltage boost at the startup.
[youtube]37ZOpoyEyEs[/youtube]
The circuit can also be easily adjusted to have a soft start. This can be useful when driving led’s etc. This way the light is not instantly bright.
[youtube]Atu8LhJ7k34[/youtube]
Dutch 
2 comments
I f add higher than 10uf on 100W 240V output and switch OFF and than quick ON you will damage mosfet so question is how to quickly discharge to prevent damage?
Author
The circuit is for 12V, not 240V.