12-hour digital clock (help)

Anyone can help me regarding this one?



(here is the link of pix above)
http://img154.imageshack.us/img154/1461/96965331.jpg


The schematic above works well in simulation (im using proteus, by d way),however,when i tried it in actual it didn't function well..

Take a look at the video in the URL below..

http://www.youtube.com/watch?v=NfIS3YnFaHs

That's what happens during simulation..But in actual,the after 12:59,it will changed to 00:00, going to 00:01, 00:02, ... , 00:59, 01:00..i hav to wait for an hour in order for it to change to 01:00..

What do u think is the problem of the schematic above?

Can anyone help me?
What will i do in order for me to attain 01:00 after 12:59?


Thanks lot!

wakeke

Anyone here knows how to make the schematic of "hours" in a 12-hour digital clock using 74LS393?

Coz we already hav a schematic of "hours" (12-hour clock) however, it is only functioning well in simulation,not in actual..

Kindyl take a look at this thread..

http://forum.allaboutcircuits.com/showthread.php?t=23186

If anyone can help me to build a schematic of "hours" (12-hour clock),will appreciate it much..


Thanks lot!


wakeke

The LS393 is a dual binary counter. When the used counter is at C, the next clock should reset the counter to 1. That's hard to do without a parallel load function, so use 0 - 11 instead.

As a further thought, use 74LS160s in place of the LS393s. They are decade counters with a parallel load function - much better suited to a clock.

beenthere said:

The LS393 is a dual binary counter. When the used counter is at C, the next clock should reset the counter to 1. That's hard to do without a parallel load function, so use 0 - 11 instead.

Click to expand...

What do you mean when the counter is at C? 0-11 is most unlikely for a digital clock...need to output 1-12...

beenthere said:

As a further thought, use 74LS160s in place of the LS393s. They are decade counters with a parallel load function - much better suited to a clock.

Click to expand...

Not familiar with this ic, how do you configure this counter for use in 1-12 hrs clock?

We're trying to connect a combination of gates & a mux to solve the 00 prob. tnx for d reply...


there's the presence of NOR gates comparing the bits of the hours and go through an AND to be used as select for the 2-1 mux....the inputs of the mux come from the clock &the other one from the AND connected to the clr pin of the 393 tens of minutes...

The LS393 is a binary counter. Twelve in decimal is C in hexidecimal.

You need a counter that has a parallel load function so it can be set to 1 instead of 0.