Simplest BCD to 7 segment circuit

Discussion in 'The Projects Forum' started by DC_Kid, Jun 17, 2009.

  1. DC_Kid

    Thread Starter Distinguished Member

    Feb 25, 2008
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    just looking for some IC suggestions for the following.

    binary (0-9) to 7 segment LED display.

    simple low cost preferred.
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    That depends upon what inputs you have already.

    Do you have the 7-segment display? If so, is it common cathode or common anode?

    Is the BCD data at TTL, CMOS, or some other level?
     
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  3. DC_Kid

    Thread Starter Distinguished Member

    Feb 25, 2008
    638
    9
    i dont have led yet, but common cathode i would choose
    level is TTL

    there are many IC's that do the job, just wondering what is common and inexpensive.

    also, anyone hear of a non-volatile 4bit counter? i see ROHM says it has one (BU70013TL) but i cant find it at any disti.
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    4511? CMOS, but I think it would work.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    Use an SN7447A. Download the datasheet from Texas Instruments:
    http://focus.ti.com/lit/ds/symlink/sn7447a.pdf

    Get common cathode 7-segment displays. It's much easier to sink current from the 7 segments with the 7447 than try to source current.

    You'll need a resistor from each cathode to the 7447 pins.
     
  6. DC_Kid

    Thread Starter Distinguished Member

    Feb 25, 2008
    638
    9
    4511 is about half the price of the 7447A

    have you ever seen a 7 segment led display that has a small pushbutton located on the bottom of the face and each press of the button has bcd output and changes the display, all in a single unit? it basically a bcd pushbutton switch, etc.
     
  7. SgtWookie

    Expert

    Jul 17, 2007
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    No. However, I do have a few LED displays that have BCD counters and drivers incorporated in them. They've been obsolete for awhile.

    If you want something really cheap just to keep track of a count, just go to the dollar tree store and pick up a pedometer for a dollar. The display is LCD, but it's completely assembled with batteries. Just connect in your own switch to make the display increment.
     
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