hi 123,
This is a LTSpice sim of your circuit, with minor modifications.
E

 

I tried to make a quiz game show circuit thingy, like the ones in Jeopardy, to have a game night with my family. My circuit doesn't work as there are 2 leds lighted up instead of 1. Other than adding a pull up to each d flip flop what else could i do? Also anyone know how to make it such that there is a certain amount of time before they cant answer anymore or like a certain sound for a wrong and correct answer.

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This is a fairly easy to follow schematic, but we have no idea what the flipflops are or what signals they use. AND with the data and enable inputs open there is no way the circuit can function.
Get two MC14013, or CD4013 FFs and use them, but with all of the unused inputs tied to common and it should work.
And you do not want inverted Qbar (Q_) outputs on a FF. Not ever.

 

Hello,

@ericgibbs , As I see the IO1 is the 5 Volts from the supply.
See the right side at the supply.
The only thing that worries me is that all labels are as output.

@electronics123 , Wich chips are you actualy using?
That way we can see wich pins need to be grounded or out high.

Bertus

chips?

 

This is a fairly easy to follow schematic, but we have no idea what the flipflops are or what signals they use. AND with the data and enable inputs open there is no way the circuit can function.
Get two MC14013, or CD4013 FFs and use them, but with all of the unused inputs tied to common and it should work.
And you do not want inverted Qbar (Q_) outputs on a FF. Not ever.

rookie mistake haha, the flip flops are cd4013s

 

hi 123,
This is a LTSpice sim of your circuit, with minor modifications.
E

wow this is really helpful thanks! will try to implement it

 

Here's a thought. Take a step back and decide what you want this thing to do. Write that out in very explicit detail. Think of all the possibilities.

For instance, it appears that you want this set up for three players. What happens if two players hit their button. Does the second player HAVE to answer, or do you just record the first player's press and lock out the other two players until the first player answers. What if someone buzzes in while someone else is answering? Should it ignore those attempts, or should it record them. Presumably is should not make a buzz under these conditions, but should it make a buzz if the player(s) that has(have) buzzed in answer wrong? After re-enabling the system after a wrong answer, do you want to keep people that have already buzzed in locked out? How much configurability do you want? Do you want to be able to adjust the time limits? How many different time limits do you want?

Walk through as many possible scenarios as you can of how the contestants might interact with the system (including doing what they are not supposed to do, such as holding down their button at the same time as the system is being reset).

That will give you a specification to which a circuit can be designed.

 

rookie mistake haha, the flip flops are cd4013s

OK, no mention of the type and no way to know. And there is NEVER an inverted sign on the Q-bar output, that is confusing.
Leaving unused inputs means that the circuit will not work correctly. EVERY CMOS input must be defined, either high or low, and not allowed to float. THAT is certainly a rookie goof.

 

Hello,

chips?

The chips are the IC's that you are using.
There are only U numbers and no types given in your schematic.

Bertus

 

Here is a project on AAC that uses a similar concept to what you’re trying. Note especially how reset is done.

https://forum.allaboutcircuits.com/threads/game-circuit.82641/

 

Below is the LTspice simulation of a game show circuit I like because of its simplicity:
It requires no logic circuits and only one active device (a small SCR) per contestant, so is very easy to exand to a large number of players.

 

I made a 3 player Jeopardy game for a friend's son a while back. I lost the code but it wasn't that difficult. The input switches are not floating. I enabled the weak pull-ups in the PIC.

 

Here is the schematic from my link.

 

Brilliant circuit, Crutschow.

The way I understand it works, the first SCR that gets triggered will clamp down the voltage at node "A" low enough such that the remaining SCRs do no have a way to provide a sufficient holding current?

 

Brilliant circuit, Crutschow.

The way I understand it works, the first SCR that gets triggered will clamp down the voltage at node "A" low enough such that the remaining SCRs do no have a way to provide a sufficient holding current?

Basically correct.
The first SCR that fires pulls the node "A" voltage below the D3 Zener voltage ("A" voltage equal to the LED + SCR forward current drop), so there's then no longer voltage at node "T" to fire any of the other SCRs.

 

Basically correct.
The first SCR that fires pulls the node "A" voltage below the D3 Zener voltage ("A" voltage equal to the LED + SCR forward current drop), so there's then no longer voltage at node "T" to fire any of the other SCRs.

This is the classic game show circuit! Nice presentation @crutschow