The PWM control field effect tube of the stc single-chip microcomputer, the power is turned on by mistake, the P4 outputs 24V at the moment of power on, and the duration is several hundred milliseconds. Theoretically, the stc single-chip microcomputer is powered on with high level, Q5 is turned on, and Q4 is blocked.
Hermione Posté sur March 2, 2021
Regardless of high or low level, Q4 is turned on. At high level, Q5 turns on.
Carlton Posté sur March 2, 2021
At the moment of power-on, the voltage drop on capacitor C9 is 0V... Try removing C9?
