1. RC low pass filter
2. RC high pass filter
For the analog PWM RC circuit, the similar feeling is that if the filter frequency is too low and the output PWM is not high enough, the amplitude of the waveform will be obvious.
R1+C1 is the charge and discharge of RC.
R3+C1 can only show the discharge index curve when discharging
C2 is powered on and starts charging. C21 is turned on during the charging process. When the capacitor is fully charged, the energy accumulation is completed and a pressure difference is formed. At this time, the capacitor does not conduct.
Because there are no capacitors, no electrons are flowing. When the button is released, the energy accumulated in the capacitor is released.
The direction of the current is counterclockwise, and according to Ohm's law, negative pressure will be generated.
The blue line starts the capacitor directly and the index line is the process of capacitor charging. The capacitor has no current after the charge is completed, and the capacitor is not conducting.
Analyze the current and current direction in the circuit.
Modifying the resistance of R2 can reduce the peak value of negative pressure.