Fastest Finger First for Buzzer Rounds in Quiz Competitions


In the buzzer round of quiz contests, the question is thrown open to all the teams. The person who knows the answer hits the buzzer first and then answers the question. Some times two or more players hit the buzzer almost simultaneously and it is very difficult to detect which of them has pressed the buzzer first. In television shows, where the whole event is recorded, the actions are replayed in slow motion to detect the first hit. Such slow motions are possible only where huge funds are available to conduct the show. For this reason buzzer rounds are avoided for quiz contests held in colleges.

This project is an electronic quiz buzzer that is affordable by the colleges and even individuals. This project is useful for a 4-team quiz contest, although it can be modified for more number of teams. This system is sensitive. The circuit can detect and record the first hit contestant among all the contestants that may appear to be simultaneous. JK master slave flip flop is the heart of this project. The complimented output of all JK flip flops is given to NAND gate input. The output of the NAND gate is fed to NOT gate. Here in this project, NOT gate is realized from NAND gate.

The output of this NOT gate is fed to CLK pins of all JK flip flops through four Push-to-ON switches. LEDs are connected to output pin of all JK flip flops through a transistor driver. Whenever any switch is pressed first, the corresponding flip flop’s output goes high and makes the LEDs blink.

This project uses regulated 5V, 750mA power supply. 7805 three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac out put of secondary of 230/18V step down transformer

Block diagram




  1. Fastest Response
  2. Highly Sensitive
  3. Wide supply range (3V to 15V)
  4. High noise immunity
  5. Low cost and reliable circuit



  1. Colleges / Schools for Quiz competitions
  2. Joel Events / Games





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3 Responses to “Fastest Finger First for Buzzer Rounds in Quiz Competitions”

  1. tejaswi says:

    can u send full details regarding this project by today evng

  2. Annu Gupta says:

    can i also have d details of dis project plzz its urgent

  3. sruthi says:

    can you send full details about this project including its construction.

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