简易烟雾警报器的设计详解.doc

简易气体烟雾报警电路设计 摘 要 随着现代家庭用火，用电量正在逐年增加，家庭火灾发生的频率越来越高，在我国由于烟雾而引起来的火灾越来越多，人民每年因此而损失了大量的财产。据调查在最近发生火灾的大多数房屋都没有安装报警器。如果发生火灾之前就有警报系统预报现场的情况，从而避免火灾的发生，对人们将会有很大的意义。因此本文对烟雾警报器系统进行研究，是具有理论和实际双面意义的。 本文讲述了简易气体烟雾报警电路，该报警器有降压整流与稳压电路，气敏传感元件和触发，报警音响电路等组成。其中气敏传感器原件使用于半导体气敏传感器QM-N5, QM-N5主要特点对液化气，天然气，城市煤气有较好的灵敏度适用于家庭或工业上对液化气，天然气，煤气的监测装置。NE555，气敏传感器报警 The Design of Simple Gas Smoke Alarm Circuit Author: Adila.aili Tutor: Li Hongxia Abstract Along with the modern family use fire and the electricity consumption increases gradually, and the family fire disaster higher frequency , in our country because of the smog is caused to more and more fire disaster, so there are many people have lost many property each year .The survey shows that the most of the family not install the gas smog alarm ,if the gas smog alarm system it can prediction of the situation, we can avoid the fire ,and it is very beneficial to human safety. So the research of the gas smog alarm that has the theory and the actual two sided significance. This article describes the simple gas smog alarm circuit , this alarms has the reduction voltage and stabilivolt circuit , gas sensitive sensor and triggered and alarm sound circuit and so on . Among them gas sensors used in semiconductor gas sensors QM-N5 , QM-N5 has better sensitivity towards liquefied petroleum gas ,natural gas industry ,city gas , and apply to home or industrial towards liquefied petroleum gas ,natural gas industry, gas monitoring device .This device circuit is simple ,reliable work ,long service life and low cost advantage. Key words: NE555, Gas sensor,Alarm 目 录1 绪论 1 1.1 1 1.2 国内外研究的现状 1 1.3 论文主要任务设计内容 2 2 系统电路设计方案 3 3 各单元电路设计 4 3.1 电源电路设计 4 3.1.1 电源变压器 5 3.1.2 桥式整流 5 3.1.3 滤波电路 7 3.1.4 集成三端稳压器 9 3.2 气敏传感器 10 3.2.1 气敏传感器的分类 11 3.2.2 气敏传感器的原理 11 3.2.3 半导体气敏传感器 12 3.2.4 QM-N5型气敏传感器 13 3.3 NE555简介 14 3.3.1 NE555的引脚图功能 14 3.3.2 NE555的工作原理 15 3.4 数据采集及处理电路设计 17 3.5 报警电路 17 3.5.1 蜂鸣器简介 17 3.5.2 蜂鸣器的结构原理 18 3.5.3 报警电路工作原理 19 4