Here is a motor speed sensor module, the major goal is to check the rate of an electric motor. The module can be used in association with a microcontroller for motor speed detection, pulse count, ...

The motor-speed-control circuit in the figure shows an SG3524 pulse-width-modulation (PWM) IC, U2, driving the high side of a motor through a p-channel FET, Q1. The motor terminal voltage is more ...