Digital Clock multisim

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ramy

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Hey, I'm trying to make a digital clock with the chips 74190N and i was able to make the seconds work it goes to 59 but whenever i try to add the 3rd one for minutes it counts up to 59 seconds but never loads the minutes. I've tried looking around and couldn't find anything I followed every instruction and still cant get it to work. I attached my design made in multisim. Hopefully someone can help me out.

Thanks in advance
 

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There you go hope that helps. My first two are counting to 59 but my third one is never counting unless it gets a 9 form the second one but I want it to start counting to 9 every 59 so I can do the other 59 which is my minutes then my hours is up to 13
 

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You're connecting the "CLK" inputs of all the 74190 together. When I simulated your circuit in my simulator I saw that both the unit and tenth seconds are stepping together.

The reason why your minute is not stepping is because 74190 is a decade counter. It would only send a pulse on P13 when it counts to ten. And since you intercept and reset it to zero when counting to "6" , it would never reach 10 so there is no pulse on P13.

Why not design in such a way that the 1 second clock pulse goes only to the "CLK" of "unit" sec counter. Its output goes to the "CLK"input of the "tenth" sec counter.... and so on. That would be much easier to make your clock work.

Allen
 

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I'm not sure if i fully understand that. Could you please elaborate on it? as in how do you suggest I would connect it from my first 74190 to the second and to the third and so on... Thanks sorry if it sounds stupid I just wanna make sure i understood well.
 
So if I understood for the next 5 for my minutes I would connect the same way as I did from my Unit seconds to my tenth seconds since its counting to 10 then for my hours I would follow how I did from tenth seconds to unit minutes? or would I do the same way as tenth second to unit minute. Also I was wondering why my way of making it reset to 5 doesn't work with this new way cause I'm not sure if we have access to 7400 chips.

Thanks a lot for the help really appreciate it!
 
You can always use 74LS00 or 74HC00 or come to the worse use 4011. I think 1 or 2 CMOS should work in a LSTTL circuit.

But always read the datasheets before you use them. Their pinouts may not be the same.....

Allen
 
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Alright, because I had used two 74LS08 and one 74LS04, but with the new way of how you told me to do it my old way of resetting it on 6 doesn't work anymore so if I find 74LS00 I could keep it this way. Also just wondering from my previous reply was I correct on how to proceed on doing the rest of my minutes and hours.. Thx
 

That's totally up to you. After all it is just a simulation - you dont need to get a cutter to cut a wire or solder a chip or go to town to buy an IC. Just try all the possibilities on the PC by clicking a mouse. Just work on it if you want to learn digital electronics.

Is this a Home Work or something? Hope I dint give too much clue so it becomes too easy to for you.

Allen
 
Haha, yea its a final project. I thought I had it all figured out, but when it came to go from seconds to minutes I spent about 7 hours going nowhere, lol. That's why I wanted to know about other chips cause I need to able to get them but I guess you're right I'll try do the rest on my own and if I can't I'll come see if someone can help me.

Thanks for your help
 
Thank you. I'll make sure to read that if I have any problems before I come asking more questions . I was able to figure out how to do it with the chips 08 and 04 the rest I'm going to have to test hopefully it works.
 
I finally got to doing my hours but for some reason its not working its a 24hr format clock i did so it resets when its at 24, but the way its counting is weird its counting 1-9 for the first till the second one gets to 4 it counts to 2 and resets. My problem is how would I manage to connect the hours to my minutes or even fix how its counting... Thanks for the help I attached both multisim and a picture of my project


Edit: I did my final version as far as I know it works but I would like for someone to let me know if what I did is right.

Edit2: nvm its not working after the minutes it wont jump to hours I dunno why

Edit3: I found out why it may have been doing that my pin 14 from U20 is supposed to go to pin 11 in U13 but for some reason my hours starts at 1
Thanks
 

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but the way its counting is weird its counting 1-9 for the first till the second one gets to 4 it counts to 2 and resets. My problem is how would I manage to connect the hours to my minutes or even fix how its counting...
Click to expand...

I am not sure I understand you here. Can you explain it clearly, maybe with a table?

Edit2: nvm its not working after the minutes it wont jump to hours I dunno why
Click to expand...

What does "nvm" mean?

After counting to "24", I see that your U22 & U20 resets to "00" hours instead of "01" (see A,B,C,D of U20).

I made a truth table for your U22 and U20 counting. Is you clock doing in that order?

Allen
 

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The first part I fixed it where I said I couldn't connect it. I was able to connect it, but for some reason my clock always start at 01 hours 00 mins 00 seconds. I'm not sure if it's how its supposed to be . When I tested just the hours it's starting from 00 going 0-9 then 1-9 then 2-4 and back to 0-1,2,3,4,5,6,7,8,9...

also nvm( never mind ) sorry it's 1:20 I got lazy for that edit

Edit: I added a picture of my last attempt where it's starting at 01 hours 00 mins 00 seconds
 

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also I realize its supposed to start 00 and resetting to 00 since after 24hrs its midnight 00 00 00, but Im still having troubles to why it's starting at 01 00 00
 
I tried looking at those links before it wouldn't let me and I even registered could you please explain what it says or how it applies to my case.

Edit: I was able to look at them. Do you mean adding a capacitor, cause we didn't learn those in my class so we wouldn't be able to use them...
 
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