chaoyic2 发表于 2013-5-6 11:07:00

红外线在人体红外探测防盗报警器中的应用

<font color="#000000"><font face="宋体">红外线</font><span style="FONT-SIZE: 14px"><span style="FONT-FAMILY: '宋体'; mso-spacerun: 'yes'"><span style="COLOR: #000000">产品</span>在</span><span style="FONT-FAMILY: 'Times New="New"Roman'; mso-spacerun: 'yes'">人体红外探测防盗报警器中的应用</span><span style="FONT-FAMILY: '宋体'; mso-spacerun: 'yes'">,主要起到报警的作用。如图</span><span style="FONT-FAMILY: '宋体'; mso-spacerun: 'yes'">1<font face="宋体">为报警器电路。它由热释点传感器</font><font face="Times New="New"Roman">B</font><font face="宋体">、菲涅尔透镜、低频带通放大器、电压比较器、开机延时电路、报警电路和电源电路等几部分组成。当有人从探头前经过时,传感器</font><font face="Times New="New"Roman">B</font><font face="宋体">输出微弱的低频信号,频率约为</font><font face="Times New="New"Roman">0.2</font><font face="宋体">~</font><font face="Times New="New"Roman">10kHz</font><font face="宋体">,经</font><font face="Times New="New"Roman">C1</font><font face="宋体">耦合给</font><font face="Times New="New"Roman">VTl</font><font face="宋体">组成的共发射极放大器进行放大,</font><font face="Times New="New"Roman">C2</font><font face="宋体">的作用是滤除高频干扰,由于经</font><font face="Times New="New"Roman">VTl</font><font face="宋体">放大后信号的幅度仍不够大,再经运算放大器</font><font face="Times New="New"Roman">A1</font><font face="宋体">构成的低通放大器进一步放大,两级放大器的总增益可达</font><font face="Times New="New"Roman">70dB</font><font face="宋体">。低通放大器的作用除滤掉干扰信号外,还可避免电路可能的高频自激。放大后的信号由</font><font face="Times New="New"Roman">A1</font><font face="宋体">送给</font><font face="Times New="New"Roman">A2</font><font face="宋体">组成的电压比较器。比较器的基准电压由</font><font face="Times New="New"Roman">R6</font><font face="宋体">和</font><font face="Times New="New"Roman">RP</font><font face="宋体">分压决定,调节</font><font face="Times New="New"Roman">RP</font><font face="宋体">,可调节.</font><font face="Times New="New"Roman">A2</font><font face="宋体">的反相输入端的比较电压。当</font><font face="Times New="New"Roman">A1</font><font face="宋体">有信号输出作用于</font><font face="Times New="New"Roman">A2</font><font face="宋体">的同相输入端且大于其反相输入端比较电压时,</font><font face="Times New="New"Roman">A2</font><font face="宋体">输出高电平,</font><font face="Times New="New"Roman">VT2</font><font face="宋体">导通,其集电极输出低电平,作用于时基电路</font><font face="Times New="New"Roman">555</font><font face="宋体">的触发端</font><font face="Times New="New"Roman">2</font><font face="宋体">脚。</font><font face="Times New="New"Roman">555</font><font face="宋体">电路与</font><font face="Times New="New"Roman">R11</font><font face="宋体">、</font><font face="Times New="New"Roman">C7</font><font face="宋体">等组成单稳态电路,延时时间由</font><font face="Times New="New"Roman">R11</font><font face="宋体">、</font><font face="Times New="New"Roman">C8</font><font face="宋体">决定:</font><font face="Times New="New"Roman">T</font><font face="宋体">—</font><font face="Times New="New"Roman">1.1R11C8</font><font face="宋体">,这里约为</font><font face="Times New="New"Roman">30s</font><font face="宋体">,当</font><font face="Times New="New"Roman">2</font><font face="宋体">脚有负脉冲、触发时,时基电路</font><font face="Times New="New"Roman">555</font><font face="宋体">进入暂稳态,在单稳态时间,即使人体感应信号消失,</font><font face="Times New="New"Roman">VT2</font><font face="宋体">不再输出低电平,</font><font face="Times New="New"Roman">VT2</font><font face="宋体">不再输出低电平,</font><font face="Times New="New"Roman">555</font><font face="宋体">电路也不再响应,直到延时结束。</font><font face="Times New="New"Roman">555</font><font face="宋体">电路的输出端</font><font face="Times New="New"Roman">3</font><font face="宋体">脚直接驱动继电器</font><font face="Times New="New"Roman">K</font><font face="宋体">,接通报警器电源,发出报警信号。</font></span></span> </font>
<p style="MARGIN-TOP: 0pt; MARGIN-BOTTOM: 0pt" class="p0"><span style="FONT-SIZE: 14px"><font color="#000000">&nbsp;</font></span></p>
<p style="MARGIN-TOP: 0pt; MARGIN-BOTTOM: 0pt" class="p0"><span style="FONT-SIZE: 14px"><span style="FONT-FAMILY: '宋体'; mso-spacerun: 'yes'"><font color="#000000" face="宋体"><img title="点击打开原图" alt="人体红外探测防盗报警器电路" align="middle" src="http://www.chaoyi1688.com/UploadFiles/FCK/人体红外探测防盗报警器电路.jpg" width="550" height="358"/></font></span></span></p>
<p style="TEXT-ALIGN: center; MARGIN-TOP: 0pt; MARGIN-BOTTOM: 0pt" class="p0"><span style="FONT-SIZE: 14px"><span style="FONT-FAMILY: '宋体'; mso-spacerun: 'yes'"><font color="#000000" face="宋体">图1:人体红外探测防盗报警器电路</font></span></span></p>
<p style="MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; MARGIN-BOTTOM: 0pt" class="p0"><font color="#000000"><span style="FONT-SIZE: 14px"><span style="FONT-FAMILY: '宋体'; mso-spacerun: 'yes'">开机时,电路设置了由<font face="Times New="New"Roman">VT3</font><font face="宋体">组成的延时开机电路。在电路刚刚通电时,由于</font><font face="Times New="New"Roman">C5/R9/R10</font><font face="宋体">阻容电路的延时作用,</font><font face="Times New="New"Roman">C5</font><font face="宋体">的充电时间约</font><font face="Times New="New"Roman">20s</font><font face="宋体">,在</font><font face="Times New="New"Roman">20s</font><font face="宋体">内</font><font face="Times New="New"Roman">VT3</font><font face="宋体">基极正偏,</font><font face="Times New="New"Roman">VT3</font><font face="宋体">导通,</font><font face="Times New="New"Roman">VT3</font><font face="宋体">的集电极将</font><font face="Times New="New"Roman">VT2</font><font face="宋体">基极信号短路到地,即使</font><font face="Times New="New"Roman">A2</font><font face="宋体">有信号输出</font><font face="Times New="New"Roman">VT2</font><font face="宋体">也不会导通。在</font><font face="Times New="New"Roman">C5</font><font face="宋体">充满电后,</font><font face="Times New="New"Roman">VT3</font><font face="宋体">失去基极电流而截止,不影响</font><font face="Times New="New"Roman">A2</font><font face="宋体">对</font><font face="Times New="New"Roman">VT2</font><font face="宋体">的左右。</font></span></span><span style="FONT-FAMILY: '宋体'; FONT-SIZE: 10pt; mso-spacerun: 'yes'"><?XML:NAMESPACE PREFIX = O /><o:P></o:P></span></font></p>
<p style="MARGIN-TOP: 0pt; TEXT-INDENT: 21pt; MARGIN-BOTTOM: 0pt" class="p0"><font color="#000000"><span style="FONT-SIZE: 14px"><span style="FONT-FAMILY: '宋体'; mso-spacerun: 'yes'">B<font face="宋体">选用</font><font face="Times New="New"Roman">SDO2</font><font face="宋体">型热释电</font></span></span><span style="FONT-FAMILY: '宋体'; FONT-SIZE: 10pt; mso-spacerun: 'yes'"><font face="宋体"><span style="FONT-SIZE: 14px"><span style="COLOR: #000000">红外传感器</span></span></font><span style="FONT-SIZE: 14px"><font face="宋体"><span style="COLOR: #000000">。菲</span>涅尔透镜用</font><font face="Times New="New"Roman">7801</font><font face="宋体">型。</font><font face="Times New="New"Roman">VT1~VT3</font><font face="宋体">均用</font><font face="Times New="New"Roman">9014</font><font face="宋体">,</font><font face="Times New="New"Roman">A1</font><font face="宋体">、</font><font face="Times New="New"Roman">A2</font><font face="宋体">选用一片双运放</font><font face="Times New="New"Roman">LM358N</font><font face="宋体">或</font><font face="Times New="New"Roman">CA3140.</font><font face="宋体">电源变压器用</font><font face="Times New="New"Roman">5V</font><font face="宋体">,</font><font face="Times New="New"Roman">220/9V</font><font face="宋体">电源变压器。其他元件无特殊要求。</font></span></span></font></p>

dzc909 发表于 2013-5-11 09:02:00

学习

ngy12721 发表于 2013-5-17 10:27:00

<p>路过学习。谢谢</p>

lc88121 发表于 2013-7-1 17:39:00

<p>学习了</p>
<p>&nbsp;</p>

车路士 发表于 2013-7-11 10:39:00

看的明白,要很长时间

zhanglinlin 发表于 2013-7-12 09:33:00

遥尔泰科技 发表于 2014-11-18 16:15:44

来学习的,图不是很懂,惭愧呀。。

无敌看家 发表于 2016-8-26 11:55:56

学习了,谢谢楼主分享~
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