Study on electrostatic capacitance concept and measurement method

Here distinguish concept of electrostatic capacitance from alternating current (Ac) capacitance, and give a calibration method for electrostatic capacitance. Considering a capacitor, there are two values of Ac and electrostatic capacitance. Both values are same only under ideal condition, yet are difference in actual conditions of considering series and parallel resistance. Two rules must be obeyed when tracing the electrostatic capacitance to Ac capacitance standard. Other than the method of using voltage source and Coulomb meter, a new measurement method is put forward by paralleling a known capacitor to calculate unknown capacitance. For instance to calibrate a metal plate capacitance on a kind of instrument named Charged Plate Monitor (CPM, also called Charge Analyzer), The measurement uncertainty is about 2%.