8 player quiz buzzer can be used in various competition organise in school and colleges to identify the team who has pressed the buzzer first. Advantage of this circuit is once a team has press the switch others are not allowed to press the switch therefore it block other participant. So with the help of this circuit you can easily identify the contestant who has press the switch first. You can use variable power supply ranging from 6V to 15V. You can provide power supply with the help of adapter readily available in market or you can make your own power supply with help of transformer and bridge rectifier. This simple circuit is based on one IC namely 74LS373 with few more easily available components. 74LS373 is a 3 state octal D type transparent latch and edge triggered flip flop.