I'm new at electronics (my new hobby) and got a lot of good responds from you guys so hope you can help me out with this one as well.
I got this an USB fan that I wanted to modulate by controlling it with some PWM.
First I did the following
D5 is the Arduino digital pins outputting the PWM. It gave a lot of noise - so thought that it might have something to do with the capacitor (C1). Just for fun I moved it around and it worked! The LED was not flickering anymore so I added another LED to see the output (like a control).
It works and I should be happy (I am :D ) - but I have some questions I hope you can help me with.
Why didn't my first attempt work _____ ? (would it work with a MOSFET?)
Is the capacitor adjusting my PWM to a linear voltage that partially opens the transistor _______?
Is the diode (D2 1N4007) placed correctly to protect induction _? (noticed that the swapping the wires of the fan does not change the rotation direction - it just don't rotate..)
Suggestions are very welcome since next step is to put it on a pref-board