国产毛片a精品毛-国产毛片黄片-国产毛片久久国产-国产毛片久久精品-青娱乐极品在线-青娱乐精品

警報器控制鍵盤電路

發布時間:2011-5-10 09:55    發布者:circuit_share
關鍵詞: 警報器 , 控制鍵盤


This switch will suit the Modular Burglar Alarm circuit. However, it also has other applications. The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals. The matrix type with 7 terminals will NOT do. Choose the five keys you want as your code, and connect them to 'A, B, C, D & E'. Wire the common to R1 and all the remaining keys to 'F'. Because your choice can include the non-numeric symbols, almost 100 000 different codes are available. The Alarm is set using the first four of your five chosen keys. When 'A, B, C & D' are pressed in the right order and within the time set by C1 and R2 (about 10 seconds), current through R11 switches Q6 on. The relay energizes, and then holds itself on by providing base current for Q6 through R12. The 12-volt output switches from the "off " to the "set " terminal, and the LED lights. To switch the Alarm off again it is necessary to press A, B, C, D & E in the right order. The IC is a quad 2-input AND gate, a Cmos 4081. These gates only produce a high output when both inputs are high. Pressing 'A' takes pin 1 high for a period of time set by C1 and R2. This 'enables' gate 1, so that when 'B' is pressed, the output at pin 3 will go high. This output does two jobs. It locks itself high using R3 and it enables gate 2 by taking pin 5 high. The remaining gates operate in the same way, each locking itself on through a resistor and enabling its successor. If the correct code is entered within the time allowed, pin 10 will switch Q5 on and so connect the base of Q6 to ground. This causes Q6 to switch off and the relay to drop out. Any keys not wired to 'A, B, C, D or E ' are connected to the base of Q4 by R9. Whenever one of these 'wrong' keys is pressed, Q4 takes pin 1 low. This removes the 'enable' from gate 1, and the code entry process fails. If C, D or E is pressed out of sequence, Q1, Q2 or Q3 will also take pin 1 low, with the same result. You can change the code by altering the keypad connections. If you make a mistake entering the code, just start again. If you need a more secure code you can use a bigger keypad with more 'wrong' keys wired to 'F'. A 16-key pad gives over half a million different codes. All components are shown lying flat on the board; but some are actually mounted upright. The links are bare copper wires on the component side. Two of the links must be fitted before the IC.
本文地址:http://m.qingdxww.cn/thread-64871-1-1.html     【打印本頁】

本站部分文章為轉載或網友發布,目的在于傳遞和分享信息,并不代表本網贊同其觀點和對其真實性負責;文章版權歸原作者及原出處所有,如涉及作品內容、版權和其它問題,我們將根據著作權人的要求,第一時間更正或刪除。
您需要登錄后才可以發表評論 登錄 | 立即注冊

廠商推薦

  • Microchip視頻專區
  • 使用SAM-IoT Wx v2開發板演示AWS IoT Core應用程序
  • 使用Harmony3加速TCP/IP應用的開發培訓教程
  • 集成高級模擬外設的PIC18F-Q71家族介紹培訓教程
  • 探索PIC16F13145 MCU系列——快速概覽
  • 貿澤電子(Mouser)專區
關于我們  -  服務條款  -  使用指南  -  站點地圖  -  友情鏈接  -  聯系我們
電子工程網 © 版權所有   京ICP備16069177號 | 京公網安備11010502021702
快速回復 返回頂部 返回列表
主站蜘蛛池模板: 日本精品国产 | 一区二区三区高清视频在线观看 | 国模肉肉大尺度啪啪人体150p | 99爱在线视频这里只有精品 | 日本高清免费h色视频在线观看 | 亚洲一区欧美 | 欧美国产视频 | 一级毛片特级毛片国产 | 久久精品视频99 | 国产成人精品三区 | 亚洲第一福利视频 | 一二三四在线社区 | 99久久99 | 中国20岁小伙男男gay | 日本色免费 | 中文日本在线 | 日韩一区二区不卡 | 成人三级在线播放 | 国产精品欧美劲爆可乐 | 男女视频在线观看网站 | 在线亚洲日产一区二区 | 欧美一二三区视频 | 青青草原综合网 | 国产黄色在线免费观看 | 九九视频只有精品 | 国产一级做a爰片久久毛片男男 | 贵州美女一级纯黄大片 | 无限免费动漫看片的 | 91精品成人福利在线播放 | 亚洲va欧美va国产 | 久久香蕉国产观看猫咪3atv | 久久99热这里只有精品国产 | 精品动漫在线观看视频一区 | 视频成人永久免费下载 | 四虎影视884aa·com | 向日葵视频免费在线观看 | 香蕉久久高清国产精品免费 | 婷婷综合在线观看丁香 | 免费av片在线观看网站 | 亚洲国产一区二区三区 | 草莓视频无限频下载-丝瓜视 |