120mm fan controller project

[tibbar]

hi

i had an idea for making a 120mm fan spin very slowly. normally if you start the fan at higher voltage and then slowly reduce it you can get it silent at about 4-5v. however, if you try and start the fan at 4-5v it won't turn because of the initial 'push' need to gain momentum.

so my idea is to be a circuit to start it on 12v and then reduce this to 4v. this could give good airflow at a very slow sound level.

any ideas on the easiest way to do this? i'm not particular good in electronics, but i think a capacitor would be involved?

any ideas

Cheers