Nominal capacity and allowable error: the ability to store electrical chargecapacitor, commonly used units are F, uF, pF. Capacitor number markedon the capacitor is the nominal capacity capacitor. The nominal capacity of the capacitor and its actual capacity there is error. In general, its capacitydirectly to write the capacitor, but also useful to sign digital capacity, usuallywhen the capacity is less than 10000pF, to do with pF units, when more than 10000pF, to do with uF units. For the sake of simplicity, capacitance greater than 100pF and less than 1uF often don't injection unit. No decimal point, its unit is pF, with a decimal point, it is a unit of uF. If the capacitor is marked with "332" (3300pF) three digits, left first, two digit two givescapacitance, and the third digit represents a number 0 in the post, the unit is pF.

Rated voltage: in the specified operating temperature range, capacitancelong-term reliability, maximum DC voltage it can bear, is also called the DCcapacitor voltage, working voltage of capacitor. If in AC circuits, attention should be paid to the maximum value of the AC voltage and the DC voltage should not exceed the value of the capacitor. Fixed capacitor voltagecommonly used with 6.3V, 10V, 16V, 25V, 50V, 63V, 80V, 100V, 120V,160V, 200V, 250V, 300V, 350V, 400V, 450V, 500V, 550V, 600V, 630V,700V, 800V, 1000V.

Insulation resistance: due to the capacitance between the poles of themedium is not absolute insulator, its resistance is not infinite, but a limitednumber, generally in more than 1000000000000000 in Europe, a resistance capacitance between the poles called insulation resistance, or called the leakage resistance, size is DC voltage rated working voltage andthe ratio of capacitor leakage current the. The leakage resistance is small,the leakage is more serious. Capacitor leakage will cause energy loss, this loss not only affects the service life of capacitor, but also affect the circuit.Therefore, the leakage resistance is bigger is better.

Dielectric loss: capacitor consumption under the action of the electric fieldenergy, usually with power loss and capacitor wattless power ratio, namely the tangent of loss angle value. Loss angle increases, loss of capacitor is greater, the capacitance loss angle is not suitable for high frequency case work.