players began to answer in the same time, start the countdown timer. If the answer in the answer in time, it was, then the digital control immediately display answering player number, while electric rings, one second and relay 1 second, that some people answer in, the answer time, only the reset button and effective, the other keys are invalid, this Press the reset button only when the host only after the next round. If no answer in the answer in time, then again count down to 0, the third group total digital display 0, indicating no answer in 2 seconds, buzzer and relay to 2 seconds, then reset button in addition to, other buttons are invalid, to enter the answer in the next round to host press the reset button.Рkeywords: Responder circuit, timing circuits, alarm circuits, timing control
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