200548604

说明：  具有定时功能的八路数显抢答器的设计 本文介绍了一种用74系列常用集成电路设计的数码显示八路抢答器的电路组成、设计思路及功能。该抢答器除具有基本的抢答功能外，还具有定时、计时和报警功能。主持人通过时间预设开关预设供抢答的时间，系统将完成自动倒计时。若在规定的时间内有人抢答，则计时将自动停止；若在规定的时间内无人抢答，则系统中的蜂鸣器将发响，提示主持人本轮抢答无效，实现报警功能。
(With regular features eight-way digital design Answer This paper introduces a series of 74 commonly used integrated circuit design of digital display devices Answer eight-way circuit design and functions. In addition to the browser Answer Answer basic functions, also has the timing, timing and alarm functions. Host through the default time for switching the default Answer time, the system will automatically countdown to complete. If the required timeframe was Answer, then the time will automatically stop if within the required timeframe Answer No, the system will be sent the buzzer ring, suggesting that the current round of presenters Answer invalid realize alarm function.)