它由主体电路和扩展电路两部分组成。主体电路完成基本的抢答功能，即开始抢答后，当选手按动抢答键时，能显示选手的编号，同时能封锁输入电路，禁止其它选手抢答。扩展电路完成定时抢答的功能。 -it from the main circuit and the circuit extended two components. The main circuit completed basic Responder function, which is to begin Responder, when activated Responder key players, the players can show that the numbers Meanwhile blockade input circuit can prohibit other players Responder. Circuit expansion completed Timing Responder function.