Stir plate

[The-Engineer-That-Brews]

If you need a simple way to control the fan speed then try this:

Should work with pretty much any old NPN transistor so long as it can handle the current.

Just to prove it works a simple series resistor might also be an option.

 

[cushyno]

Yep, fans running too fast. My homemade stirplate does the same if I crank up the voltage.

 

[jayk34]

Fan's running far too fast mate - that's your problem
Also, you need to start with the fan stationary, then get the stir bar in position and being held by the magnets before you turn the power on

Thanks. That's it sorted now when I put it on lowest setting. Feel like a bit of a tool now

Thanks all for the help.

 

[The-Engineer-That-Brews]

Feel like a bit of a tool now

Please don't - we all enjoy helping people: it makes us feel clever