QUIZ BUZZER

NOW  TODAY  WE DISCUSS ABOUT ONE OF THE CHARACTERISTIC OF 555NE  TIMER IC   .
SINCE WE CAN  SAW MANY REALITY SHOW IN WHICH THERE IS BUZZER ALARM IS USED HERE WE USED BULB  INDICATION INSTEAD OF BUZZER

IN CIRCUIT DIAGRAM YOU  CAN EASILY SHOW THAT 555 TIME IC USE IN BISTABLE MODE HAVING TWO STABLE OUTPUT .THEREIS 5 SWITCH OF DOOR BELL IS USED i.e S1,S2,S3,S4,S5 AND FOR VOLTAGE CONTROLLER 7805 IC IS USED 

BASIC OPERATION OF CIRCUIT IS THAT WHENAVER  ANY PARTICIPANT PRESS  IMMEDIATELY KEY THEN OTHER THEN CORRESPONDING RELAY ON BY ELECROMECHANICAL OPERATION THAT ON RESPECTIVELY BULB 1,2,3,4OR ,5 WILL BE GLOW . THERE IS MASTER RESET KEY  USED AFTER ONE QUESTION WILL BE COMPLETED TO RESET WHOLE CIRCUIT  AND MAKE READY FOR NEXT QUESTION .