all about wiring diagram

Quiz-type sport shows are increasingly more becoming well-liked on tale imaginative and prescient at the current time. In such games, quickest finger first indications (FFFIs) are used to check the player’s response time. The participant’s special number is dis played with an audio alarm when the participant presses hellos entry button. The circuit presented here decides as to which of the four contestants first pressed the button and locks out the rest three entries. Simultaneously, an audio alarm and the proper decimal number display of the corresponding contestant are activated. 

Fastest Finger First Indicator Circuit Diagram

 

When a contestant presses hellos change, the corresponding output of latch IC2 (7475) adjustments its common sense state from 1 to zero. The combinational circuitry comprising dual four-input NAND gates of IC3 (7420) locks out subsequent entries by way of producing the fitting latch-disable sign. Priority encoder IC4 (74147) encodes the active-low enter situation into the cor responding binary coded decimal (BCD) quantity output. The outputs of IC4 after inversion by inverter gates within hex inverter 74LS04 (IC5) are coupled to BCD-to-7-segment decoder/display driver IC6 (7447). The output of IC6 drives common-anode 7-segment LED show (DIS.1, FND507 or LT543). 

The audio alarm generator includes clock oscillator IC7 (555), whose output drives a loudspeaker. The oscillator frequency will additionally be varied with the help of preset VR1. Logic zero state at probably the most outputs of IC2 produces common sense 1 input situation at pin 4 of IC7, thereby enabling the audio oscillator.  IC7 needs +12V DC provide for sufficient alarm stage. The last circuit functions on regulated +5V DC supply, which is acquired the use of IC1 (7805). Once the organiser identifies the contestant who pressed the change first, he disables the audio alarm and on the similar time powers the digital show to ‘0’ by means of pressing reset pushbutton S5. With a moderate change, this circuit can accommodate greater than four contestants. 

Author : P. Rajesh Bhat  – Copyright : EFY