![Amazon.com: MEIRIYFA 3 Pin 4 Pin Fan Adapter PWM PC Chassis Cooling Fan Hub 8 Way Splitter DC12V Speed Controller with 6 Pin Power Port,Chassis Fan Pressure Regulating Governor : Electronics Amazon.com: MEIRIYFA 3 Pin 4 Pin Fan Adapter PWM PC Chassis Cooling Fan Hub 8 Way Splitter DC12V Speed Controller with 6 Pin Power Port,Chassis Fan Pressure Regulating Governor : Electronics](https://m.media-amazon.com/images/I/71Aus2t3r5L._AC_UF894,1000_QL80_.jpg)
Amazon.com: MEIRIYFA 3 Pin 4 Pin Fan Adapter PWM PC Chassis Cooling Fan Hub 8 Way Splitter DC12V Speed Controller with 6 Pin Power Port,Chassis Fan Pressure Regulating Governor : Electronics
![arduino - how to read and control the speed of a 12V - four wire fan? - Electrical Engineering Stack Exchange arduino - how to read and control the speed of a 12V - four wire fan? - Electrical Engineering Stack Exchange](https://i.stack.imgur.com/ToTSf.png)
arduino - how to read and control the speed of a 12V - four wire fan? - Electrical Engineering Stack Exchange
![Controlling a 4-wired fan PWM Signal using Arduino allows only two settings - Electrical Engineering Stack Exchange Controlling a 4-wired fan PWM Signal using Arduino allows only two settings - Electrical Engineering Stack Exchange](https://i.stack.imgur.com/cmwAy.jpg)