【摘要】 本文介绍了小型防盗防火报警器的工作原理、技术指标、设计电路和试验情况。提出了提高人体感应传感器灵敏度的技术措施和提高报警器工作可靠性和稳定性的方法。更多还原

【Abstract】 Mini-alarm guarding against theft and fire has been made. The theftproof part of this device is made on the principle of capacitance change made by the humanbody’s induction.To increase sensitivity, traditional oscillating switch has been changed to bridge circuit. This increased the proportion of inductive signals of humanbody to interference signals and enhances the circuit ability of resistance to outer interferences as well. Capacitive coupling used in cascade connecting circuits can dicrease the zero fluctuation and increase stability. Theftproof circuit gives an alarm when humanbody is 30 cm from the sensor. If functions well under the interference of household electrical equipments, automobiles and motors. Probe made of entectic metic used as a sensor in fireproof part breaks to give alarm when the ambient temperatare reaches its fusing point.更多还原