主控开关先复位，然后再断开，选手开始抢答，译码显示出来，同时，选手答题的计时开始，到计时为0后，报警电路有效，开始报警。然后主控开关进行复位，准备下一轮的的抢答。用multisim进行仿真。-Master switch to reset, and then disconnect, players start Answer, decoding displayed at the same time, players begin to answer in time to time to 0, the alarm circuit effective start alarm. Master switch and then reset, ready for the next round of the Answer. Simulation using multisim.