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在业余无线电制作活动中,经常用到低频信号发生器。下面向大家介绍一台电路简单、实用易做的低频信号发生器,供大家参考。一、电路原理: 信号发生器的电路图见图1,这是一个互补管RC振荡器,主要由RC串并联选频网络和BG1、BG2、BG3三级互补管直接耦合放大器组成,其中BG1、BG2为增益可调的放大器,BG3为射极跟随器,用来作阻抗变换以获得较低的输出阻抗,可减少晶体管输入输出阻抗对选频网络的影响。由于BG1、BG2间加有R6、R7、R8等构成的深度负反馈,因而放大器的性能相当稳定。为进一步稳定振荡幅度,还把输出电压经热敏电阻R4反
In amateur radio production activities, often use low-frequency signal generator. Here to introduce a simple circuit, easy to use low-frequency signal generator, for your reference. First, the circuit principle: The signal generator circuit shown in Figure 1, which is a complementary tube RC oscillator, mainly by the RC series shunt frequency selection network and BG1, BG2, BG3 three complementary tubes directly coupled amplifier, BG1, BG2 The gain-adjustable amplifier, the BG3 emitter follower, is used for impedance transformation to achieve a lower output impedance, reducing the effects of transistor input-output impedance on the frequency-selective network. As BG1, BG2 plus R6, R7, R8, etc. formed by the depth of negative feedback, so the performance of the amplifier is quite stable. In order to further stabilize the oscillation amplitude, but also the output voltage by the thermistor R4 reverse