电子课程设计_三路抢答器.doc

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1、.目录前言································································11方案设计·························································22主要单元电路···················································42.1二输入4与非门74LS00·········································42.2三输入3与非门74LS10·····························

2、···········52.3四D触发器74LS175············································62.4555定时器构成的多谐振荡器··································72.4.1555....定时器··················································72.4.2555定时器构成的多谐振荡器·······························82.5抢答器按键部分············································

3、····92.6抢答器指示部分···············································103总电路原理图及设计原理·····································124总结与体会·····················································14参考文献·························································15附录元器件清单·················································

4、16....前言电子课程设计是对以前学科知识的综合，检验学生掌握电子学科的理论知识的程度，也是学科教学中的一个十分重要的环节。通过把理论与实践相结合，提高理论水平，锻炼实践动手能力。同时，对于学生对电子学科的学习兴趣也是有极大的激发作用，让同学在自己动手制作的过程中找到乐趣，加深对学科知识的理解及消化，为以后的学习打下良好的基础。一个较为复杂的设计课题，通常需要对设计要求进行认真分析和研究，通过收集和查阅资料，在已学模拟和数字电子技术课程（或电子技术）理论的基础上进行构思，从而提出实现设计要求的可能方案，并画出相应的框图。抢答器是一个用于智力抢答的简易器械，通过他可以实现对由谁获得回

5、答权的自动判断，假如仅靠人的判断，很难保证先做出抢答的选手获得答题权，运用抢答器可以消除这种可能性从而保证比赛的公平公正性。抢答器多见于一些益智类节目中，抢答器可以锻炼选手的快速反应能力，而且活跃现场气氛。本报告主要介绍了简易三路抢答器的设计原理以及器件选择和主要器件分析以及原理图等。....1方案设计图1-1三路抢答器的流程图如图为这个三路抢答器的方案流程图，其具体介绍如下：选手抢答按键由三个可自动复位开关组成；多谐振荡器由555....定时器和电容和电阻构成；主持人复位键使用一个可自动复位按键；声光提示部分由三个发光二极管和一个扬声器构成；抢答信号分析主体部分由一个四D触发器74

6、LS175和两个二输入与非门（由74LS00提供）和一个三输入与非门（由74LS10提供）构成。该抢答器工作流程：抢答开始前，主持人按下复位键，此时，三个发光二极管均为熄灭状态，扬声器不发声。当主持人表示开始抢答时，选手按下抢答器按键，和该选手对应的指示灯即发光二极管亮，扬声器发出声音，同时通过与非门电路将抢答信号反馈回来，锁住抢答器主体，使之不再接收其他选手的抢答信号，从而保证只有第一个按下抢答按键的选手获得答题权。等到进入下一抢答环节，主持人按下复位键，抢答器再次处于可抢答状态。....2主要单元电路2.1二输入4与非门74LS00图2-1二输入4与非门74LS00的部逻辑图74

7、LS00有外部14个管脚，部由四个二输入与非门电路构成。现取其中一个列其功能表：Y=表2-1二输入与非门功能表....输入输出ABYLLHLHHHLHHHL2.2三输入3与非门74LS10图2-2三输入3与非门74LS00的部逻辑图74LS10有外部14个管脚，部由三个三输入与非门电路构成。现取其中一个列其功能表：Y=表2-2三输入与非门功能表....输入ALLLLHHHHBLLHHLLHHCLHLHLHLH输出YHHHHHHL2.3四D触发器74LS17