一、原理图1是平均值检波器的电路原理图.如果不看BG_3、BG_4的集电极电路,以它们的发射极作输出端,它便是一个典型的交流串联电压负反馈放大器.它的重要特性之一,就是当放大器的开环增益很大而负反馈又很深时,尽管BG_3、BG_4基极无偏置电流而处于静态截止状态,当BG_1的基极输入交流信号u_i时,由于深度的负反馈将使BG_3、BG_4发射极“输出”的交流 First, the principle of Figure 1 is a schematic circuit of the average detector.If you do not see BG_3, BG_4 collector circuit, with their emitter as the output, it is a typical AC series voltage negative feedback amplifier. Its One of the important features is that when the open loop gain of the amplifier is large and the negative feedback is very deep, although BG_3 and BG_4 base are in the static cut-off state without bias current, when the base of BG_1 inputs AC signal u_i, The negative feedback of depth will make BG_3, BG_4 emitter “output” AC