12-hour digital clock (help)

Discussion in 'The Projects Forum' started by wakeke, May 7, 2009.

  1. wakeke

    Thread Starter Member

    Nov 29, 2008
    11
    0
    Anyone can help me regarding this one?

    [​IMG]

    (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
     
    Last edited: May 7, 2009
  2. wakeke

    Thread Starter Member

    Nov 29, 2008
    11
    0
    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
     
  3. Wendy

    Moderator

    Mar 24, 2008
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  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    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.
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    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.
     
  6. wakeke

    Thread Starter Member

    Nov 29, 2008
    11
    0
    What do you mean when the counter is at C? 0-11 is most unlikely for a digital clock...need to output 1-12...

    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...

    [​IMG]
    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...
     
    Last edited: May 7, 2009
  7. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    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.
     
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