数字式竞赛抢答器主要由74 系列集成电路组成。该抢答器除具有基本的抢答功能外, 还能实现定时、报警和抢答信号的鉴别和首个抢答锁存等抢答相关的多功能。在初始状态主持人掌握整个抢答电路的复位键个开始抢答键，在抢答开始的时候，主持人先将电路复位，接着按下开始键，即可进入30s常规抢答；若在按下开始键之前抢答者按下按钮，电路则会报警（所对应的组的led灯将会点亮），电路将自动扣去提前抢答的组的10分。在有人抢答到后，电路会锁存第一个抢答到的组号，并进入120s答题时间，答对加分，答错则扣分。6个组别原始分数为100分，加减分均为10分/次；计时均为倒计时。本设计的优点在于课题要求的基本功能可以通过仿真实现、各单元电路都在不同方案的基础上择优选取了其中实现功能最多，电路最精简的方案；而本设计的缺点在于总电路过于庞大，用Multisim运行过程缓慢、仿真容易出现错误，同时实物接线复杂易错。(The digital contest Responder is mainly composed of 74 series integrated circuits. In addition to the basic function of the emergency response, the emergency response device can realize the multiple functions related to the emergency response, such as timing, alarm, identification of the emergency response signal and the first emergency response lock. In the initial state, the host holds the reset keys of the whole emergency response circuit. At the beginning of the emergency response, the host resets the circuit first, and then presses the start key to enter the 30s routine emergency response. If the responder presses the button before pressing the start key, the circuit will give an alarm (the LED light of the corresponding group will be on), and the circuit will automatically buckle the 1 of the group in advance emergency response 0 points.)