课题四 555定时器的原理及应用

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1、in 26 cases, long-term measures to implement the rate is 77% deployed 40 couples free pre-pregnancy health checks. -Balanced development of education. I attach great importance to control fits and starts work, to ensure that school-age children to school on time, hope dream poor students go to schoo

2、l to help poor students, help students complete nine years of compulsory education. Township school-age children enrollment rate up to 100%. -Home to poverty alleviation work in order. Complete the rural minimum living standard security system and the effective connection between pro-poor developmen

3、t policies, establish the Township poor electronic records and paper file documentation work, and cooperate with the superior unit holders, such as the statistical work of the poor masses. As of now, I enjoy the low 94 families, a total of 305, 44310 rural minimum living standard security issued org

4、anization 7 operational training full-time staff with disabilities participated in the County Federation organized 15 disabled people to participate in free training in farming skills; organization of 14 patients with cataract receiving free checks, participate in the examination will now undergo su

5、rgery had been successful. -Waste management policy in place. Seriously implement the subsidy policies such as direct subsidies for grain, returning farmland to forests this year agriculture agricultural policy subsidies total 554940, of which: farmers direct subsidies for grain 389880; reforestatio

6、n subsidies 165060. -Comprehensive management of public security work steadily. Full implementation of the measures for comprehensive management of social security, increasing crackdown on all illegal and criminal activities. As of now, my alarm 30 received, 7 all kinds of disputes, mediation succes

7、sfully 6; State criminal case 3, case 7, has been investigating the 7. -Stabilisation work of letters and calls for further strengthening. Received mass petitions from 10 successful mediation, 8, investigation 1, collective skipping appeal event does not occur. Meanwhile, further strengthen publicit

8、y and mobilization work, carried out in schools, kindergartens and surrounding environment group woven fire safety and food safety 6 times, 1 traffic safety publicity and education, legal literacy, drug pictures and materials via issuing 600 and guard against cult of special publicity activities 2 a

9、ttended by 300 people, mixture of anti-evil propaganda 70. Advancing the law of six thematic activities, through the easy way, with the film projectionist the village broadcast education 44, 3600 people returning to watch. -Further development of spiritual civilization construction work. Evening lei

10、sure time, organizations in the elderly in the rural culture of Hui Xiang Hui fitness dance square, greatly enriched the lives of the masses. Use of Arbor Day, 51 labor day, May Fourth youth day festivals, organize the education campaign for the festive, educational guide people to foster patriotism

11、, socialism, collectivism and strengthen love and loyalty to the party, firmly follow the party go . Implementation of the one gang double responsibility established number one responsibility, team member management works. Five are team building. Open-minded, innovative ways to meet the actual needs

12、 of target, combining education and political education in party lecture, unified planning, unified plan, take active measures to enhance cadres quality and ability. (B) a solid foundation steadily promoting the construction of理实一体化课程教师教案（20122013学年 第 一 学期） 专业名称 高级维修电工 课程名称 高级电子单片机 授课教师 李明 郭涛 系 部 电气

13、工程系 唐山劳动技师学院理实一体化教案首页教学模块高级电子单片机任课教师李明 郭涛审阅 授课时数章节课题理论课时 教学方法实训课时 基本教材合计课时 授课班级授课时间教学目标1知识目标：2能力目标：3素质目标：教学分析教学重点教学难点教案说明教学设计1组织教学1组织教学 2复习旧课 3引入新课 4讲授新课、模仿练习 5归纳总结 6布置作业 7板书设计 课题四 555定时器的原理及应用【理论讲解】旧课复习：1、LED数码管的工作原理及应用2、7448驱动电路的原理及应用新课引入：555定时器是一种多用途的数字模拟混合集成电路，利用它能极方便地构成施密特触发器、单稳态触发器和多谐振荡器。由于使用灵

14、活、方便，所以555定时器在波形的产生与交换、测量与控制、家用电器、电子玩具等许多领域中都得到了广泛应用。本课主要介绍555定时器的工作原理及其在单稳态触发器、多谐振荡器方面的应用。正课内容：一、555定时器（一）555定时器的简介555定时器是一种多用途的数字模拟混合集成电路，利用它能极方便地构成施密特触发器、单稳态触发器和多谐振荡器。由于使用灵活、方便，所以555定时器在波形的产生与交换、测量与控制、家用电器、电子玩具等许多领域中都得到了广泛应用。自从signetics公司于1972年推出这种产品以后，国际上个主要的电子器件公司也都相继的生产了各自的555定时器产品。尽管产品型号繁多，但是

15、所有双极型产品型号最后的3位数码都是555，所有CMOS产品型号最后的4位数码都是7555.而且，它们的功能和外部引脚排列完全相同。（二）555定时器的应用（1）构成施密特触发器，用于TTL系统的接口，整形电路或脉冲鉴幅等； （2）构成多谐振荡器，组成信号产生电路； （3）构成单稳态触发器，用于定时延时整形及一些定时开关中。 555应用电路采用这3种方式中的1种或多种组合起来可以组成各种实用的电子电路，如定时器、分频器、元件参数和电路检测电路、玩具游戏机电路、音响告警电路、电源交换电路、频率变换电路、自动控制电路等。（三）555定时器的电路结构与工作原理图 1555 定时器的功能主要由两个比较

16、器决定。两个比较器的输出电压控制 RS 触发器和放电管的状态。在电源与地之间加上电压，当 5 脚悬空时，则电压比较器 C1 的同相输入端的电压为 2VCC /3，C2 的反相输入端的电压为VCC 若触发输入端 TR 的电压小于VCC /3，则比较器 C2 的输出为 0，可使 RS 触发器置 1，使输出端 OUT=1。如果阈值输入端 TH 的电压大于 2VCC/3，同时 TR 端的电压大于VCC /3，则 C1 的输出为 0，C2 的输出为 1，可将 RS 触发器置 0，使输出为 0 电平。 它的各个引脚功能如下： 1脚：外接电源负端VSS或接地，一般情况下接地。 8脚：外接电源VCC，双极型时

17、基电路VCC的范围是4.5 16V，CMOS型时基电路VCC的范围为3 18V。一般用5V。 3脚：输出端Vo 2脚：低触发端 6脚：TH高触发端 4脚：是直接清零端。当此端接低电平，则时基电路不工作，此时不论TR、TH处于何电平，时基电路输出为“0”，该端不用时应接高电平。 5脚：VC为控制电压端。若此端外接电压，则可改变内部两个比较器的基准电压，当该端不用时，应将该端串入一只0.01F电容接地，以防引入干扰。 7脚：放电端。该端与放电管集电极相连，用做定时器时电容的放电。 在1脚接地，5脚未外接电压，两个比较器A1、A2基准电压分别为的情况下，555时基电路的功能表如表1示。表 1清零端高

18、触发端TH低触发端Q放电管T功能0xx0导通直接清零101x保持上一状态保持上一状态110x保持上一状态保持上一状态1010110导通截止置1清零二、555定时器与触发器的联系3.1、555定时器构成单稳态触发器图 2上图为由555定时器和外接定时元件R、C构成的单稳态触发器。D为钳位二极管，稳态时555电路输入端处于电源电平，内部放电开关管T导通，输出端Vo输出低电平，当有一个外部负脉冲触发信号加到Vi端。并使2端电位瞬时低于1/3VCC，低电平比较器动作，单稳态电路即开始一个稳态过程，电容C开始充电，Vc按指数规律增长。当Vc充电到2/3VCC时，高电平比较器动作，比较器A1翻转，输出Vo

19、从高电平返回低电平，放电开关管T重新导通，电容C上的电荷很快经放电开关管放电，暂态结束，恢复稳定，为下个触发脉冲的来到作好准备。波形图见图3。 图3 单稳态触发器波形图暂稳态的持续时间Tw（即为延时时间）决定于外接元件R、C的大小。 Tw=1.1RC 通过改变R、C的大小，可使延时时间在几个微秒和几十分钟之间变化。当这种单稳态电路作为计时器时，可直接驱动小型继电器，并可采用复位端接地的方法来终止暂态，重新计时。此外需用一个续流二极管与继电器线圈并接，以防继电器线圈反电势损坏内部功率管。三、555定时器接成多谐振荡器多谐振荡器又称为无稳态触发器，它没有稳定的输出状态，只有两个暂稳态。在电路处于某

20、一暂稳态后，经过一段时间可以自行触发翻转到另一暂稳态。两个暂稳态自行相互转换而输出一系列矩形波。多谐振荡器可用作方波发生器。 图 4 多谐振荡器和工作波形接通电源后，假定是高电平，则T截止，电容C充电。充电回路是VCCR1R2 C地，按指数规律上升，当上升到时（TH、端电平大于），输出翻转为低电平。是低电平，T导通，C放电，放电回路为CR2T地，按指数规律下降，当下降到时（TH、端电平小于），输出翻转为高电平，放电管T截止，电容再次充电，如此周而复始，产生振荡，经分析可得 输出高电平时间 T=(R1+R2)Cln2 输出低电平时间T=R2Cln2 振荡周期 T=(R1+2R2)Cln2 四、5

21、55定时器在现实生活中的应用实例图 5 门控灯开关该控制电路的核心是555定时器和D型触发器。555定时器接成单稳态触发器,去除触点跳动对电路工作的影响,D型触发器接成 T触发器形式,利用其输出去控制可控硅开通和关闭,从而控制电灯的亮灭。平时当房门关闭时,安装在门扇边缘的小磁铁正好靠在干簧管旁边,干簧管的两常开触点受外磁力作用吸合,单稳态电路因输入脉冲为高电平而处于待触发状态,此时双稳态电路的输出为低电平,可控硅因无触发电流而阻断,灯不亮。当有人推门时,小磁铁会随门扇离开干簧管一次,干簧管的常开触点会因暂时失去外磁力作用而靠自身弹力张开、吸合一次。实际上,由于干簧管的触点的抖动,要重复几次这种

22、张开、吸合的过程.单稳态触发器的 CP 端能够在干簧管的1触点第一次张开时获得一负脉冲触发信号,使单稳态触发器翻转为暂稳态,其输出由低电平变为高电平此时,电容器 C 经 R 充电,复位端 R 电位上升,当上升到复位电平2/3V 时,单稳态触发器复位,Q 恢复为低电平。单稳态电路的时间常数 T=1.1R C ,它有效地将干簧管的具有抖动信号现象的脉冲信号展宽为单个脉冲,此正脉冲同时加至 T触发器器的 CP2端,其输出由低电平变为高电平,可控硅的控制极获得正向触发电流而导通,电灯通电发光.当进来的人离开时,随着门的再一次打开、关闭,干簧管重复同样的动作,单稳态触发器同样输出一正脉冲信号,于是T触发

23、器再次翻转为低电平,可控硅失去触发电流并在交流电过零时关断,电灯自动熄灭。光敏电阻 R 和可调电阻 R 构成光控电路。在白天 ,光敏电阻受自然光照射阻值很小 ,T触发器的置“0”端 R电位 1/2V ,无论此门被开闭多少次 ,DD电路强制置“0”,Q始终为底电平 ,电灯不会发光;夜晚 ,因自然光照减弱 ,T触发器的置“0”端 R 电位 1/2V ,强制复位自动解除。实际应用时,将开关盒安装在门框顶上,小磁铁则正对着盒内底侧部放置的干簧管固定在门扇顶沿上。仔细调整小磁铁和干簧管的相对位置,使干簧管能够随门扇的开闭而可靠地动作。然后,根据“火线接开关地线进灯头,接通开关和灯头”的照明灯接线原则,将

24、开关盒内桩头外引线不分顺序串入电灯火线回路即可。最后,用小螺丝刀将 R 调至阻值最小的位置,P在夜晚需要开灯的时候,打开门扇使灯点亮,然后由小到大调节R 阻值,直到电灯刚好熄灭,再将 R 阻值回调一点即可.反复细调,即可获得最佳光控灵敏度。5 结论555 定时器把模拟电子中的放大功能和数字子的逻辑功能融合起来 ,定时精确 ,电源范围宽直接推动负载.因此 ,作为一种价格低廉、性能优使用方便的中规模的集成电路 ,555 定时器已成数字电路中最常用的时基电路之一 ,必将在控制域得到更广泛的应用.探究活动：课题：1、用万用表区分共阳LED数码管和共阴LED数码管组织形式：个人、学习小组活动方式：制定活

25、动内容。2、 小组讨论、总结、交流。【实操训练】 555定时器控制二极管顺序点亮（一）实训目的1、认识555定时器的引脚排列及接法2、认识CD4017的引脚排列及接法3、掌握循环灯电路的安装及调试（二）器件清单标号值/型号数量LED1-LED8发光二极管8个C120014个C27448译码器2个R1、R210K2个R3、R44702个RP50K1555集成块1CD4017集成块1排线若干（三）电路图原理分析四、 实习报告要求1、 画出电路原理图2、说明电路的工作原理3、根据调试中出现的故障现象分析其原因五、评分标准内容要求配分评分标准说明布局各个元器件的布局清晰、美观、合理10布局不合理每处扣

26、1分走线清晰，线程短，无跳接线10焊点1、焊点有足够的机械强度2、焊接可靠，保证导电性能。3、焊点表面整齐、美观：焊点的外观应光滑、清洁、均匀、对称、整齐、美观、充满整个焊盘并与焊盘大小比例合适。20（1）焊点粗糙、拉尖、有焊接残渣，每处扣1分（2）引线过长、焊锡不擦干净，每处扣1分，扣完为止调试在规定时间内，利用仪器仪表调试后进行通电试验60（1）通电调缺少完整的功能扣5分（2）调试过程中损坏元件，每只扣2分，扣完为止六、归纳总结【教学体会】grass-roots party organizations is focus of new party members. Further stren

27、gthening the party education campaign, party organization to more excellent talents absorbed, constantly enhance the partys vitality and vigor, a solid job discovery, training activists. The initiative to broaden the scope of training, at the village level organization of young cadres, wealth expert

28、s and other personnel in the discovery, selection, training, and guide them to move closer to the party and injected fresh vitality to the building of rural grass-roots party organizations. Second is to further improve the site present situation of grass-roots party branches. With an emphasis on con

29、struction of village-level activities, comprehensive corrosion activities of grass-roots party organization construction in various fields, with village-level party organization function setting, achieving more efficient use of venues, activities for grass-roots party organizations and party members

30、, and create good conditions for serving the masses, by using village-level activities. Third is to conscientiously implement the village group living subsidy distribution work. In strict accordance with the parent document, fully according to the actual situation, further improve the village cadres

31、 of the group registration through the one card uniform forms, living subsidies timely payment on time each month to the hands of village cadres of the group, to ensure, without delay, not in arrears, and to ensure that earmarks. Four village election preparations are made. Organization survey and t

32、he Xiang village cadres, a comprehensive understanding of the village Committee. Using visited members, and masses representative and village group cadres of form, understand masses by wants to, and by needed, and by hope; through held members will, and masses will and village group cadres will, und

33、erstand village level organization status, and exists highlight problem and future development direction; visited understand complex back soldiers, and workers returned young personnel and masses recommended of rich capable, full reserve cadres team, for village two Board general election lay solid

34、based. (C) to speed up the pace of the adjustment of industrial structure and increase farmers income through various channels. One is to strengthen its efforts to readjust the industrial structure. At the same time accelerate the process of industrialization in rural areas, and actively promote the

35、 development of industries with local industry and quality, reasonable and effective solution to my single issues of the industrial structure, for example: turtle and introduced sheep farming project, strengthening the educational plant support. Second, broaden the channels of sales of agricultural

36、products. Actively carry out famous brand construction of agricultural products, to create brand agriculture, expand marketing channels, enhance brand awareness and market competitiveness of farm products. Third, strengthening agro-technical training. Through training, to improve the scientific qual

37、ity of peasants, farmers quality of life, promote the surplus labor force transfer output, really be my shortcut to rural farmers for agricultural development. Four is the comprehensive strengthening of the construction of ecological environmental protection, further establishing ecological compensation mechanism construction of ecological construction and industry, development of local characteristic, strongly supports the ecological transition Industrial construction, focus on the development of