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Fastest Finger First circuit..Help

Discussion in 'General Electronics Discussion' started by jvports, Dec 3, 2016.

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  1. jvports


    Dec 3, 2016
    Hi! I need help with my project. I couldn't understand how the circuit in the picture operates. The ICs used are NE555 ICs and the diodes are 1N4007 diodes. Basically, the circuit works like a two-player quiz buzzer that could be seen in game shows. There are three buttons: one for reset button and two for each player. Once a button is already pushed, the other one is disabled unless the reset button is pushed. Thanks in advance!

    Attached Files:

  2. 73's de Edd

    73's de Edd

    Aug 21, 2015

    Sir jvports . . . .

    Hmmmmmmmm . . . your fritz . . . just had a fritz . . . .when I tried to mag it up a bit.

    So there you have two identical circuits, sitting there, waiting to be triggered.
    The trigerring occurs . . .in a FLASH . . . . just as soon as either switches low logic signal derived from that 1K resistor l is switch connected to the top contact of the lucky / fastest switch.

    When that occurs that lucky 555 switches to high logic state on its pin 3 output at the far right side, and that supplies a circuit path of power to its LED and it lights up.
    SIMULTANEOUSLY its PINK boxed 1N4007 is steering a voltage down to change the state of the switch line so that the other switch will not be able to produce a change at its associated 555.

    On reset the circuits are set up to start play again.

    FIRST PLAY 555 circuit.jpg

    73s de Edd
    Last edited: Dec 4, 2016
  3. jvports


    Dec 3, 2016
    Thanks a lot sir for answering my question! I owe you a lot! I still have questions to ask if it's okay with you. I would just like to know the functions of the three capacitors in the circuit and the 10k ohm resistors too. Thank you a lot sir!
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