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该话机使用全内置和弦音乐及来电显示芯片CD838,降低了整机成本,提高了整机的可靠性与稳定性。电路如图1所示。现简述其工作原理。一、振铃电路的工作原理振铃电路由IC1(UTC2411)及外围元件组成。振铃时,交换机送来的25Hz/90V铃流信号,经耦合电容1C1、1C1A和限流电阻1R1、1R1A送到由1D1～1D4组成的桥式整流电路整流,由1C2滤波,1ZD1稳压成直流电压后送到IC1①脚,使内部振荡器和功率放大器工作,从⑧脚输出双音频信号,经1C5及音频输出变压器1T1推动扬声器振铃。电路中1R4、1C4A决定
The phone uses a full built-in chord music and caller ID chip CD838, reducing machine costs and improve the reliability and stability of the machine. Circuit shown in Figure 1. Now briefly describes its working principle. First, the ringing circuit works Ringing circuit by the IC1 (UTC2411) and the external components. Ringing, the switch sent 25Hz / 90V ring current signal, the coupling capacitor 1C1, 1C1A and current limiting resistors 1R1, 1R1A sent to 1D1 ~ 1D4 formed by the bridge rectifier rectifier circuit, by 1C2 filter, 1ZD1 regulator DC voltage sent to IC1 ① feet, so that the internal oscillator and power amplifier work, from the ⑧ pin output dual audio signals, the 1C5 and audio output transformer 1T1 to promote the speaker ring. Circuit 1R4, 1C4A decision