This video talks about Sallen-Key active filters. This is a simple topology used to implement second order active filters. We see why you use active filters instead of the passive ones and the transfer function of this particular second order low-pass filter.
From capacitor to passive filters: https://youtu.be/SfHEcOZId-I
Miller Effect: https://youtu.be/TD3jhSzOdqI
Negative Resistance: https://youtu.be/RuRQpavgOtM