A click board for the fans. For controlling 4-wire fans to be exact, the type that cools computers and other electronics.
Contribute to the overall entropy in this world and suck out the warmth from any PCB, no matter how high powered and hot the circuitry is. All you need is a big enough fan, and a means of controlling it. Fan click, carrying the EMC2301 controller, provides the latter.
The top of the board has a connector with four pins. It’s a widely used standard developed by Intel. The four wires are: PWM, which controls the motor, TACH, which gives RPM feedback, and two wires for the power supply, in this case 5V.
Since TACH provides the feedback, Fan click can control how hard the ventilators work with a high degree of precision. The accuracy is within 1% in the range between 500 and 16k RPM.
The higher end of the RPM scale will probably wear out your fans quicker. To prevent any damage to the circuitry in case the worst happens, the EMC2301 IC can send an interrupt in case the fan gets stuck. Detection of aging fans is also incorporated.