精品文档---下载后可任意编辑一 摘要: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呼叫器的电路组成、设计思路及功能
该呼叫器除具有基本的呼叫功能外,还具有定时、计时和报警功能
工作人通过时间预设开关预设供呼叫的时间,系统将完成自动倒计时
若在规定的时间内有人呼叫,则计时将自动停止;若在规定的时间内无人呼叫,则系统中的蜂鸣器将发响
关键词:八路, 呼叫器, 设计,定时,计时,呼叫Abstract:In this paper, the electric circuit and designing thought of an answering racer based on the common-used series of 74 IC with 8-wire is introduced, and its function is also described
The answering race’s function includes timing, counting, and alarming, besides the basic function of an answering racer
The host sets the provided time for the answering race through the time-setting switch, after this the system will count down the time automatically
If anybody answer the question on time, the counting of time will stop; If nobody answer the question on time, the alarm will give out som