Accurate clock signal & more

Discussion in 'General Electronics Chat' started by happs, Mar 3, 2005.

  1. happs

    Thread Starter Member

    Feb 27, 2005
    Hey peeps

    From what I have learnt I have managed to make some pretty nifty little LED effects and pretty lights. I have also learnt about the 4017 decade counter and the 4060 binary counter; I would like to make some sort of clock, whether it be with 7 segment LED displays or some other method. I am sure I can work out how to wire up the IC's so they work correctly and display the time (tho not yet tried, heh) but my main query on this project is about precise timing.
    I can use a 555 timer to provide the clock pulses but would this be precise enough ? It needs to be a proper 24 hour clock, so needs to be accurate, and for some reason I have a feeling that maybe a 555 timer does not provide the most accurate oscillator (oooh .. good techy word there .. heh, still learning the terms). Am I correct in thinking this, and if so, what do you guys suggest I use as a replacement ? Any other suggestions or help you can offer on this matter would be great also.

    AND ... heh ...
    Anyone know the correct way to have a 4060 BCD IC reset at 8 .. at the moment my 4060 is going all the way up to 15, I need it to go .. 0,1,2,3,4,5,6,7,8

    Thanks in advance

    - Alex
  2. vikas singh chauhan

    New Member

    Mar 4, 2005
  3. beenthere

    Retired Moderator

    Apr 20, 2004

    You're out of luck with the 4060. Q4 is a count of 16. The lowest stage counter outputs Q0. You'd need the Q3 output for a count of 8.

    Consider using the AC line for your timebase. The 60 Hz freq is held to one part in 1,000,000. Lots more accurate than a 555 timer, even with really good components. The attachment has a 1 Hz clock generator I made up for a project. If you want, you can restrap the counters for 50 Hz if that's your line frequency
  4. happs

    Thread Starter Member

    Feb 27, 2005
    Hiya :)

    Thanks for the reply guys, much appreciated. It's a shame to hear about the 4060 limitation, heheh - but thats one new thing learned :) Was thinking it could maybe be possible if I used an AND gate on counts A and D ? (or if it switches on falling edge, B and D). I dunno if that would really work, I don't even know how to make an AND gate yet, lol - but thats another lesson for another day.

    As for posting the circuit diagram for the 555 timer circuit I am using, Vikas, it's a standard err ... whats the word .. astable 555 circuit. I can't really post a circuit diagram cuz I dunno how to draw them neatly enough yet. Heheh.

    - Happs (alex)