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Each contestant has a latch for his button, so that once he presses his button his latch it is set for good, and no further pulses can come from it. Each contestant also has his own counter. The output from a contestant's latch sends a clock pulse to everyone's counter (including his own) but disables any further clock pulses to his own counter only. The count on a contestant's counter shows what order he pressed his button. The only problem with this, is that every contestant must press his button, or there will be more than one counter with the same count on it until every contestant presses his button. Maybe that is not a problem, though.
I don't know what the relay you mentioned is for. One relay is not going to tell you which contestant was first, second, third, and so on.
ok i making a quiz table using relays where the contestant who first presses the button get to answer the question something like wheel of fortune. but i need a way to know who press 2nd and 3rd..etc
can use other components too
I put this circuit together, as an example. It can be expanded to add a 4th player by adding another button/latch. Only a single counter is necessary as the output of the counter is latched into the respective player's output register. The problem where a player does not push his button is addressed by disabling the output of his register, thus none of his lamps will be lit.
This a good example of a job best handled by a microcontroller, or gate array, as you can see the number of parts and connections involved.