本设计主要由红外线传感器、信号放大电路、电压比较器、延时电路、音响报警电路、开机延时电路和电源电路组成。人体时时刻刻都在发射人眼不可见的红外波，但是可以被红外线传感器Q74接收，只是这个信号很小。经过前级三极管放大和后级运算放大器LM358放大之后，信号放大到足够大。在电压比较器LM393和延时电路的控制下，能够很好的实现，当有人出现在一定感应范围内时，探测防盗器自动报警。-The design mainly by infrared sensors, signal amplifier, voltage comparator, the delay circuit, sound the alarm circuit, power-delay circuit and power circuit. The human body all the time firing the human eye invisible infrared waves, but can be infrared sensors Q74 receiver, but the signal is very small. After the first stage transistor amplifier and the LM358 op amp level after amplification, signal amplification is large enough. In the voltage comparator LM393 and under the control of the delay circuit, to achieve good, when someone in a certain range of sensors, the detection of anti-theft alarm automatically.