该抢答器主要运用到了编码器，译码器和锁存器：它采用74LS148来实现抢答器的选号，采用74LS279芯片实现对号码的锁存，采用74LS192实现十进制的减法计数，采用555芯片产生秒脉冲信号来共同实现倒计时功能，采用74LS121单稳态芯片来实现报警信号的输出。-The buzzer is mainly applied to the encoder, decoder and latch: it USES 74 ls148 to achieve responder pick, the number is realized by using 74 ls279 chip latches, decimal subtraction is realized by using 74 ls192 counter, using 555 chip to produce second pulse signal to realize the countdown function, using 74 ls121 monostable chip to realize the alarm signal output.