这次设计的抢答器主要四部分组成，由优先编码器，寄存器和译码器组成的抢答电路，十进制计数器组成的倒计时电路，555定时器组成的秒脉冲发生器，十六进制计数器组成的计数器。-The design of the Responder mainly of four parts, by the priority encoder, register, and the composition of the answer in the decoder circuit, consisting of decimal counter countdown circuit, 555 timer pulse generator consisting of seconds, consisting of the hexadecimal counter counter.