Nominal capacity and allowable error: capacitor's ability to store charge, commonly used unit is f, uF and pF. Capacitor capacitor is a capacitor marked on the nominal capacity. Nominal capacity and the actual capacity of the capacitor has some errors. In General, write it directly on the capacitor capacity, it also uses digital signs capacity, usually when the capacity is less than 10000pF, do with pF units, larger than 10000pF when do with uF units. For simplicity, than 100pF capacitor of 1uF is often not note units. Without a decimal point, and it is measured in pF, decimal point, it is the unit of uF. If the capacitor marked "332" (3300pF) three digits, left two of capacitance is given first to second digits, and the third digit indicates that the added number of 0, the unit is pF.
Rated working voltage: within the specified operating temperature range, capacitance to work reliably for a long time, it can withstand the maximum DC voltage, is the capacitor voltage, also known as the DC voltage of the capacitor. In AC circuits, pay attention to the AC voltage and the maximum value cannot exceed the DC capacitor voltage value. Commonly used fixed capacitor voltage 6.3V, 10V, 16V, 25V, 50V, 63V, 80V and 100V, 120V, 160V, 200V and 250V, 300V, 350V, 400V 450V 500V, 550V, 600V, 630V, 700V, 800V, 1000V.
Insulation resistance: due to capacitive insulators between the poles of the medium is not absolute, its resistance is not infinite, but a limited number, generally in more than 1000 megohms, capacitance between the poles of resistance called the insulation resistance or leakage resistance, size is under rated operating voltage DC voltage and capacitor leakage current ratio. Leakage resistance is smaller, the more serious the leakage. Capacitive leakage can cause energy loss, this loss is not only affect the life expectancy of capacitor and circuit work. Therefore, the leakage resistance of bigger is better.