The mounting of capacitors on a circuit board usually consists of a small section of pinout drawn from the pad, and two or more vias. We know that parasitic inductance exists in both leads and vias. Parasitic inductance is an important parameter of our main concern because it has the greatest impact on the characteristics of the capacitor. After the capacitor is installed, a small area around it can be effectively decoupled, and the capacitor itself has parasitic inductance. The path from the capacitor to the area that needs to be decoupled includes the pad, a small lead-out line, vias, and 2 cm long power and ground planes, all of which have parasitic inductance.