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Design a latch circiut

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Dukey

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Hi,

I'm designing a circuit to check 13 switches (a panel of machine)
I want to make a circuit that can keep the history of pressed switch
show by 13 led lights.This is to make sure I check them all.

When check again I can press reset all light turns off.
I found that 74HC74 D-flip flop would be suit, but I have to use many 74HC74.

Is there a better method by using only few ICs.

Thank you.

Duke..
 

There is one way to solve that.

1.) Connect tour switch to the D input o fthe Latch 74X74 or 74X75. I think its 74x75.

2.) Connect your LED to the output.

3.) Don't forget to add clock to the Latches
 

You can use this latch IC 74HC273. It has 8 D-FlipFlops.
 

What's wrong with seven 74HC74 chips? They are cheap. Too bulky?

You could use thirteen small SCRs. Each button turns on one SCR, which lights its LED. The reset button is normally-closed, and simply breaks the DC power to the whole project, thereby resetting all the SCRs. High technology! Of course, a small SCR costs about the same as a 74HC74.

Some folks use PIC microcontrollers for everything. You could do that here. They are small and cheap.
 

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