non-multiplexed digital clock question

Discussion in 'The Projects Forum' started by cbuchakjian, Feb 13, 2009.

  1. cbuchakjian

    Thread Starter New Member

    Feb 13, 2009
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    gentlemen and ladies,
    I am attempting to build a digital clock with a four 7-segment characters. Each of my segments is a A/C device switched by an SSR. Is there a digital clock circuit which can drive four 7-segment characters without Multiplexing?
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    Of course - you simply use one 7 segment driver per display. Can a 7 segment driver IC actually turn on your SSR's, or do you need to buffer the logic output?
     
  3. cbuchakjian

    Thread Starter New Member

    Feb 13, 2009
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    Thank you for your response. I should let you know that my knowledge of electronic circuits is somewhere between beginner and monkey. Multiple seven segment driver ICs makes sense to me. What IC combination would you recommend for the actual timing.

    Hmm, what is the possibility that I could bump up the D/C output from the seven segment display so that the SSRs would still operate, say, 10 feet away?
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    4000 series CMOS is pretty available and functional. CD4029's are easy enough to use, a CD4511 or CD4513 will run the displays.

    Lots easier to keep the relays close and just wire over to the displays. You do know that SSR's latch on with DC? Probably do ok with rectified but not filtered DC. CMOS can't handle power, so sone buffer might be needed between the logic output and the SSR's.

    Any particular reason for using SSR's? There's less expensive ways to switch DC currents.
     
  5. cbuchakjian

    Thread Starter New Member

    Feb 13, 2009
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    I chose the SSRs because they were the first thing that made sense to me for switching 2 amps of A/C with a small D/C current. If there is a more elegant (less expensive) solution I am all ears.
     
  6. beenthere

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    I'm confused. When you said -
    - imagined you were dealing with DC.

    How are the 7 segment displays to be lit?
     
  7. cbuchakjian

    Thread Starter New Member

    Feb 13, 2009
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    each segment of the 7-segment digit will we be a 3', T-12 fluorescent fixture. I just moved to a new workshop with a large wall perfectly suited for a 6' digital clock
     
  8. beenthere

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    Can't see why it won't work as long as you're using the right ballasts.

    Will the logic be able to control the SSR's?
     
  9. cbuchakjian

    Thread Starter New Member

    Feb 13, 2009
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    I was able to get a ballast to fire by poking around on a clock that I built from a kit. The SSRs fire, but they don't react well to the mutiplexed signal. I believe that was your question.

    Where would I find plans for a clock circuit with four 7-segment decoders?
     
  10. beenthere

    Retired Moderator

    Apr 20, 2004
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