噪声检测与报警电路设计分析

Analysis on design of noise detection and alarm circuit

文章介绍了一种利用运放LM358作为放大器并通过单片机检测、设置噪声大小产生报警的电路。通过驻极体采集声音信号,经运放两级放大后送入电压比较器,当外部噪声大于设定的数值时,运放输出高电平对电容充电,从而使三极管导通一段时间后,继电器吸合,接通报警电路进行报警。报警灵敏度可通过调节电位器的大小实现。

A kind of circuit using LM358 as amplifier to detect and set noise set through the single-chip detection to alarm is introduced in this paper.Sound signal is acquired through electret, after two stage amplified, it is sent into a voltage comparator.When external noise is grater than the set value, the amplifier output high voltage to charge the capacitor, so that the triode can breakover for certain time, the relay can actuation switch on the alarm circuit alarm. The alarm sensitivity by adjusting the size of the potentiometer.