diy fan controller question

[skrsh3r]

Hi everyone i'm new here and i wanted to know how can i add kickstart to this circuit.


Thank you.

 

[johan851]

Kickstart? I'd say that if you want to run fans at such a low voltage that they won't start, you should get slower fans and dial those down less.

Also, something about that circuit looks weird, but it's been a long time since I did anything with BJTs. Seems like you won't have hardly any voltage control in that configuration.

 

[Bobnova]

Shouldn't the NPNs go on the ground side of the motor?
Regardless, it can be done.

This is something I drew up and tested, it'll work nicely with that setup IF the transistors really are switching voltage as they are in your schematic, not ground.



If you're switching ground you can do the pretty much the same thing with a NPN MOSFET if you change things around a bit.

 

[skrsh3r]

Well i tested it and i can dial voltage from 5.1v to around 10v with 1 amp load but i cant seem to figure where to put cap to get kickstart.

Anyway thank you Bob ill try that.