2015-6-5 The parameters of the patch capacitance
The main parameters of the chip capacitor are nominal capacity and allowable deviation, rated operating voltage, insulation resistance, temperature coefficient, capacitance loss and frequency characteristics, etc.. (the patch capacitance, the "capacitor")
1 the nominal capacity of the capacitor and the allowable deviation mark the capacitance of the capacitor as the nominal capacity. The actual capacity of the capacitor and the nominal capacity of a certain deviation, the nominal capacity of the capacitor and the actual capacity of the maximum deviation range, called the allowable deviation of the capacitor. The error of the nominal capacity and the actual capacity of the capacitor reflects the accuracy of the capacitor.. In general I, II, III common capacitance, electrolytic capacitor with V, VI, IV.
2. Capacitor rated voltage is refers to the capacitance in the specified temperature range to the highest voltage of continuous and reliable work, sometimes also rated DC voltage and AC rated working voltage. The size of the rated working voltage is related to the medium and the ambient temperature of the capacitor.. The ambient temperature is different, the maximum operating voltage that the capacitor can withstand is also different. When selecting the capacitor, according to its working voltage, the rated operating voltage is greater than the actual working voltage, in order to ensure the capacitor is not breakdown. Common fixed capacitor operating voltage of 10V, 16V, 25V, 50V, 63V, 100V, 400V, 500V, 6.3V, 630V, 1000V, 2500V. The voltage values of the general direct nominal capacitance, but some of the electrolytic capacitor voltage using color standard method, the location near the anode lead to qualify for the root.
3 the temperature change of the capacitor can cause the small change of the capacitance, usually with the temperature coefficient to express the capacitance of this characteristic. Temperature coefficient is defined in a certain temperature range, the temperature of each change of 1 degrees, the capacity value will change with.
4 capacitor leakage of the medium is not absolutely insulation, there will always be leakage current leakage. The leakage current of electrolytic capacitor is relatively large, and the leakage current of other capacitors is small.. When the leakage current is large, the capacitor will be fever; when the fever is serious, the capacitor will be damaged due to overheating..
The 5 capacitor insulation resistance and insulation resistance value is equal to the voltage at both ends of the capacitor and the capacitor leakage current ratio. The insulation resistance of capacitor is related to the material and area of the dielectric material and the material of the wire, the material and the length of the wire, the manufacturing process, the temperature and the humidity.. For the same kind of medium capacitor, the greater the capacitance, the smaller the insulation resistance.. The size and the change of the insulation resistance can affect the working performance of the electronic equipment. For the general electronic equipment, the higher the insulation resistance is, the better.
6 the frequency characteristic of capacitor is the characteristic that the capacitance has the performance of different frequency (i.e., the electric parameter changes with the change of circuit operating frequency).. The capacitance of different dielectric materials, the maximum frequency is different, for example, capacity larger capacitance (such as electrolytic capacitors) only in the low-frequency circuit work normally, and high frequency circuit can only use smaller capacity of high-frequency ceramic capacitor or mica capacitors.
7. The capacitance of the dielectric loss and capacitor is consumed in the electric field of energy, usually power loss and capacitance ratio of reactive power, namely loss angle tangent value. The larger the loss angle, the larger the loss of the capacitor, the larger the loss of the capacitor is not suitable for the high frequency case..