认识贴片电容（Recognize the patch capacitance）.doc

认识贴片电容（Recognize the patch capacitance） Recognize the patch capacitance Capacitance unit is: method (F), micromethod (uf), skin method (pf). Usually we dont use the unit because its too big. The conversion between units is: 1 f = 106 uf??????? 1 uf = 106 pf 1 f = 103 mf = 106 uf = 109 nf = 1012 pf In use, we often see the unit: nf. 1 uf 1000 nf =?????? 1 nf = 1000 pf Several methods of capacitance identification: if the value is 104, the capacity is: 10X10000pf = 0.1uf. If the value is 473, that is 47X1000pf = 0.047 uf. (the next four, three, are all ten to the power of ten.) Also like: 332 = 33X100pf = 3300pf. ? What are the advantages of a capacitive patch? Save space for high integrated circuit design High reliability, high accuracy, enhanced anti-interference ability Safer, less prickly What is the role of the patch capacitor? The main effect is to eliminate the interference of other chips by the various high-frequency signals generated by the chips themselves, so that each chip module can work without interference. In the high frequency electronic oscillation circuit, the lamp-type capacitance and the crystal oscillator are composed of the oscillator circuit, which provides the required clock frequency for various circuits. The lamp-type capacitance is of ceramic capacitance, lamp-type tantalum capacitance and lamp-type aluminum electrolytic capacitance. The ceramic capacitance is nonpolar and the capacity is small (PF), which can be high in temperature and voltage, often used in high frequency filtering. Ceramic capacitors look a bit like patch resistors (so sometimes we call them patch capacitors), but the patch capacitance does not represent the size of the capacitance. Patch type tantalum capacitor is the feature of long life, high temperature resistant, high accuracy and high frequency filter change wave performance is wonderful, but capacity is smaller, the price is more expensive than aluminum capacitor, and the ability of resistance to voltage and curre