The nominal safety capacitance is the safety capacitance marked on the safety capacitor. The basic unit of safety capacitor is Farah, or F for short. However, this unit is too large and seldom adopted in field labeling.

Other units are related below：1F=1000mF　　1mF=1000μF　　1μF=1000nF　　1nF=1000pF　The deviation between the actual safety capacitance and the nominal Safety Capacitance of the safety capacitor is called the deviation, and the tolerance is called the accuracy in the allowable deviation scale.　

Correlation between accuracy grade and admissble degree：00（01）-±1%、0（02）-±2%、Ⅰ-±5%、Ⅱ-±10%、Ⅲ-±20%、 Ⅳ-（+20%-10%）、Ⅴ-（+50%-20%）、Ⅵ-（+50%-30%）　Level I, II, III, and level IV, V and VI for electrolytic safety capacitors are selected according to their applications.

Additional voltage can be continuously added to the maximum DC voltage RMS of the regulated capacitor at the lowest ambient temperature and the additional ambient temperature. Normally, it is directly labeled on the shell of the regulated capacitor. If the working voltage exceeds the resistance of the regulated capacitor, the regulated capacitor will break down and cause irreparable permanent damage.

The DC voltage of insulating resistance is added to the regulated capacitor and generates discharge current. The ratio of the two is called insulating resistance. For example, ceramic regulated capacitor and metallized film capacitor, the bigger the insulating resistance is, the better the insulating resistance is, while the smaller the insulating resistance such as aluminium electrolytic regulated capacitor is, the better the insulating resistance is.　

Time Constant of Safety Capacitor：In order to properly evaluate the large-capacity insulation environment, a time-delay constant is introduced, which is the product of insulation resistance and capacity.耗The energy consumed by fever in a unit of time under electric field induction is called consumption.Various safety capacitors prescribe their allowable consumption in a certain frequency range. The consumption of capacitors is mainly caused by dielectric consumption, conductivity consumption and resistance of all metal departments.

Under the influence of DC electric field, the consumption of ceramics safety capacitor exists as leakage conductance consumption, which is usually small.在Under the influence of alternating electric field, the consumption of safety capacitor is not only independent of leakage conductance, but also independent of periodic polarization process.Frequency characteristics with the rise of frequency, as usual, the safety capacitance of safety capacitors appears to reduce the discipline.The temperature coefficient of the safety capacitor is within a certain temperature scale, and the absolute change value of the safety capacitance at 1 ℃The smaller the temperature coefficient, the better.