3 WIRE FAN CONTROL CIRCUIT

PIC 3-Wire Fan RPM Controller - PCB Heaven
Unfortunately, this circuit has a major drawback. It is not always sure that it will work with every 3-wire fans. I mean, you could use a 4-wire fan and be sure that it works (and also remove the FET as the 4-wire fans have it built-in), but the title talks about 3-wire fans. I tried some other fans.
Why and How to Control Fan Speed for Cooling Electronic
INTRODUCTIONHEAT GENERATION AND REMOVALFAN TYPESFAN CONTROLSUMMARYInterest has been growing in integrated circuits for controlling the speed of cooling fans in personal computers and other electronic equipment. Compact electrical fans are cheap and have been used for cooling electronic equipment for more than half a century. However, in recent years, the technology of using these fans has evolved significantly. This article will describe how and why this evolution has taken place and will suggest some useful approaches for the designer.See more on analog