旁路,耦合及退藕电容作用（Bypass, coupling and decoupling capacitance）.doc

旁路,耦合及退藕电容作用（Bypass, coupling and decoupling capacitance） What is the bypass? Bypass (Bypass), in the circuit in order to change the frequency characteristics of a certain branch, makes it in some frequency memory in the appropriate value, but it is similar to short circuit state in some frequency range, so it leads to the concept of bypass capacitor. The reason for the bypass capacitor bypass capacitor, because it is next to the existence of a main road, and not some capacitors are meant to do bypass capacitor that is to say, what kind of capacitor can be used as a bypass capacitor, the key lies in the capacitance value of the appropriate size or not. The bypass capacitor is not a patent for electrolytic capacitors or ceramic capacitors. The reason why the majority of bypass capacitors in low frequency circuits are electrolytic capacitors is that the capacitance of ceramic capacitors is difficult to reach the required size. The purpose of using the bypass capacitor is to make the bypass capacitor short-circuit to the main circuit for signals above a particular frequency. As shown in the form: the bypass capacitor is required to be of size; Scoring Report Superman2012 Assistant Engineer Points 1088 Posts 280, this month online 1 hours 45 minutes Expert level: Tie rate: 79% 3# Superman2012 published in 2013-4-3 22:32:16 | only see the author | return page reply comments Known: 1, bypass capacitor to flow through the resistor R frequency is higher than f AC signal approximately short-circuit. What is the size of the bypass capacitor? Solution: the purpose of C is to bypass capacitor at frequencies of f more than originally through the vast majority of the R short circuit; the frequency of F, which is far less than the resistance value of R=1/2 f*C C=1/2; Pi Pi f*R When f=1khz, R=1k, C should be much larger than 0.16uf. The 47uF has been close enough, of course, be a little larger too, 100uF still can accept, can make the appropriate increase of the bypass capacitor mo