Capacitance (or capacitance) is a physical quantity that represents the capacity of a capacitor to hold charge. Mainly used in power filter, signal filter, signal coupling, resonance, filter, compensation, charge and discharge, energy storage, DC isolation circuit. The capacitance is determined by C=εS\/4πkd. Where ε is a constant, S is the opposite area of the capacitor plate, d is the distance of the capacitor plate, and k is the electrostatic constant. A common parallel plate capacitor has a capacitance of C=εS\/d (ε is the dielectric constant of the medium between plates, S is the plate area, and d is the distance between plates). Definition: capacitor potential energy calculation formula: E=CU^2\/2=QU\/2=Q^ 2\/2c Multi-capacitor parallel calculation formula: C=C1 C2 C3... Cn multi-capacitor series calculation formula: 1\/C=1\/C1 1\/C2... 1\/Cn three capacitors in series: C= (C1*C2*C3)\/(C1*C2 C2*C3 C1*C3)