摘要： 下面是 [便携式麦克风前置放大电路]的电路图　　该电路是一个低噪音的基础上，高增益两个阶段PNP和NPN晶体管放大器，利用通过R6的直流负反馈稳定的工作条件比较准确。BOM表 P1 = 2.2K R1 = 100K R2 = 100K R3 = 100K R4 = 8.2K R5 = 68R R6 = 6.8K R7 = 1K R8 = 1K R9 = 150R C1 = 1uF-63V C2 = 100uF-25V C3 = 100uF-25V C4 = 100uF-25V C5 = 22uF-25V Q1 = BC560 Q2 = BC550