Two-fan rotating speed monitoring circuit device

The utility model discloses a two-fan rotating speed monitoring circuit device. The two-fan rotating speed monitoring circuit device comprises a rotating speed signal collection circuit, a signal comparison circuit and a warning signal output circuit. The rotating speed signal collection circuit comprises a passive magnetoelectric rotating speed sensor. When metal blades of fans pass the detection end of the passive magnetoelectric rotating speed sensor, the passive magnetoelectric rotating speed sensor will output a voltage signal. The signal comparison circuit comprises a voltage comparator chip. When the voltage signal output by the passive magnetoelectric rotating speed sensor gets access to a circuit board, the voltage signal is compared with an adjustable reference voltage signal on the circuit board. The warning signal output circuit comprises an LED circuit. When the rotating speed of either fan is abnormal, all red LEDs on the circuit board will give a lamplight warning. According to the two-fan rotating speed monitoring circuit device, the functions of two-fan rotating speed monitoring and abnormity warning are achieved by using a simple analog circuit, the rotating speed of the two fans can be monitored, the circuits are simple, and reliability is high.