Help in a 12 hours clock

Discussion in 'The Projects Forum' started by TulioTC, Aug 7, 2014.

  1. TulioTC

    Thread Starter New Member

    Aug 7, 2014
    Hey, my name is Tulio. I'm 17 years old and atm i'm working on a 12 hours digital clock.
    Okay, I've used the 74LS93 to do divided by 10 and divided by 6 counters to build the seconds and minutes section and its working pretty well.

    To make the hours section I've based on this:


    Ok, its working well too but the problem is, it counts from 0 to 11 and reset to 0.
    I'd like some help to make it reset to 1 once the counter reaches 12. Someone suggested me to use JK flip-flops, I tried but failed, maybe cuz' i'm a beginner xD.

    Thanks in advance.
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    The way I would do it is to change IC2 to a 74LS161 type which has a synchronous load input. That way on the 11th hour when the next clock pulse comes thru instead of just resetting to zero (undesirable) instead you can load 0001 and get the desired result.
  3. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    Load 0000 after eleven or 0001 after twelve?
  4. MrChips


    Oct 2, 2009
    I would use two BCD counters such as 74LS160.
    Detect 12 and on the next clock pulse (synchronous LOAD) load 01.
  5. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    Ummm... yeah, that would be load 0 0001 (for 1) after 1 0010 or 12.