Planning to build myself a homemade stir plate. I've read couple of tutorials and I'm left with some questions lol.
I'd like to wire the fan to a potentiometer so I can control the speed.
1. I intend to use a pc fan (80mm) or something. I've read against using brushless fan as you can't control the speed. How do you see if it's brushless?
2. What is the potentiometer I need. I see people say 25 ohm (http://www.homebrewtalk.com/f51/diy-...easier-225340/
and other people say 1k ohm (http://seanterrill.com/2010/04/26/bu...ter-stirplate/
Does it make much of a difference? Why does it work with both.
How do I calculate the required ohm? Because I will go the my electronic shop tomorow and see what fans then have in stock. If the ohm is important I should know how to calculate it.
3. I see that I should get a 2W rated potentiometer to avoid it melting because of the dissipated heat. In the second link I provided up there I know the guy says the best method is with the LM317T and yada yada, but fact is I'm a real amateur in this domain so I'd like to keep it simple for now. Maybe one day I'll do something like he said (His instruction are not simple enough for a noob like me).
So if I get a 2w rated one, I should be fine right?