如果你必须在一对铜导线上传输直流电和音频信号,则图1所示电路可能对你有所帮助。这种电路的一种用途就是采用语音输入的廉价开门系统。该电路仅使用一块集成电路,即众所周知的廉价电源稳压芯片LM317。使用这一芯片,就能用来自电容式驻极体话筒的音频信号调制调整引脚的输入信号。驻 If you have to carry both DC and audio signals over a pair of copper wires, the circuit shown in Figure 1 might be useful to you. One use of this circuit is the cheap door opener system with voice input. The circuit uses only a single integrated circuit, the well-known cheap power regulator chip LM317. Using this chip, you can use the audio signal from the condenser electret microphone to modulate the input signal of the adjustment pin. Resident