Described here is a simple electronic circuit which can be used in any test or quiz competition. Features of this circuit are:Whenever a switch is pressed, the [[wysiwyg_imageupload::]]circuit locks the remaining three entries. It has a master reset switch which allows users to press the switch next time once they have pressed. It can be powered from variable power supply ranging from 5V to 15V.Initially it may possible all or may two LED will be glowing for that you have to first clear the flip flop by pressing reset switch. Under this condition Q output of IC2 and IC1 become low.Continue reading to find out assembling and working of the circuit with video.
Quiz games are becoming very popular these days. The main concept behind these games is the use of fastest finger first indicators which are used to test the [[wysiwyg_imageupload::]]reaction time of the contestants. When the players press the button then the designated player’s number is displayed with the use of audio-visual alarm. The project here has a circuit that can be used for 2 players or teams only. It can be used to identify which of the two has first pressed the button and locks out the other on. The project is made up of two 555 timers which are sometimes known as Schmitt trigger as they work in bistable state i.e. produce either a low or a high output. In this circuit when the trigger input is low the output of the circuit becomes high and when the reset input is low the output also becomes low.