New Simple 555 Integrated Digital Tachometer Circuit

As shown in the figure, the turntable, that is, the rotating wheel to be tested, the sensor for detection uses the SH13 type Hall integrated circuit. When the mounted small magnetic steel turntable rotates, the Hall device will perceive the magnetic signal and record it. After amplification, the F1 non-gate is inverted, and is added to the NAND gate F5.555 and R3, RP1, C2, etc. to form a typical no. Steady-state multivibrator.