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本文介绍的报警器无须外接专用线路,靠电力线传输报警信号,可设置多处警点并对警情进行声光报警,适用于仓库、楼群住宅等需防护的单位和场所。工作原理该报警器由发射和接收显示两部分组成,发射电路原理如图1所示。它是由两块555时基电路构成的两个不同频率的振荡电路,当CK两端短路时(探头报警),第1块555构成的低频振荡电路的频率f1由C1、R2决定,并在3端输出频率为f1、占空比为50％的低频信号。当f1为高电平时,第2块555构成的高频振荡电路工作,其振荡频率f2由C3、R4决定,且f2>>f1,则在第2块555的3端输出宽度为1/2f1、频率为f2的脉冲调幅
This article describes the alarm without the need for an external dedicated line, by the power line transmission alarm signal, you can set multiple police points and the police sound and light alarm, apply to the warehouse, residential buildings and other units and places to be protected. Working principle The alarm by the launch and reception shows two parts, the launch of the circuit shown in Figure 1. It consists of two 555 time base circuit composed of two different frequency oscillator circuit, when CK short circuit (probe alarm), the first block 555 composed of low frequency oscillator circuit frequency f1 by C1, R2 decision, and in 3-terminal output frequency f1, 50% duty cycle low-frequency signal. When f1 is high, the second high-frequency oscillation circuit 555 work, the oscillation frequency f2 by the C3, R4, and f2 >> f1, then in the second 555 3-terminal output width of 1 / 2f1 , The frequency of f2 pulse amplitude modulation