Seven Segment Displays

Discussion in 'The Projects Forum' started by magikal, Dec 29, 2008.

  1. magikal

    Thread Starter Active Member

    Nov 23, 2008
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    I got hold of some LC3011-11 seven segment displays, but I cannot find a data sheet for them anywhere on the net. Does anybody know the pin order or anyway I can test they out?

    Also does anybody have information on how to connect 4 seven segment displays to the ICL7107 chip for 2V full range??

    Thanks
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    If they are single units, the pinout is pretty standard. Any 7 segment display should give you the correct pinout. The common pin is usually one of the middle pins.

    The remaining mystery is determining if they are common anode or common cathode. If you have a meter with a PN junction function, it's easy to see which way the LED's conduct. Otherwise, you will need a voltage source and current limiting resistor.
     
  3. magikal

    Thread Starter Active Member

    Nov 23, 2008
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    Could you send me a link to a page with the standard pin out? Also what is the difference between anode and cathode?
     
  4. hgmjr

    Moderator

    Jan 28, 2005
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    It would be helpful if you could post a digital picture of the front and rear of the 7-segment display.

    hgmjr
     
  5. magikal

    Thread Starter Active Member

    Nov 23, 2008
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    I cant take a picture right now, but it has 10 pins in 2 rows. On the side, it says LC3011-11. It has a dot like thing (maybe a decimal point?) on both sides of the standard 8.
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
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    The pinout should be the same as for an LA-601.

    1. - e
    2. - d
    3. - common
    4. - c
    5. - dp
    6. - b
    7. - a
    8. - common
    9. - f
    10. - g

    Where pin 1 is the lower left pin with the dp to the lower right of the segments.
     
  7. magikal

    Thread Starter Active Member

    Nov 23, 2008
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    Ok thanks, can anybody tell me how to change the configuration of the ICL for anode/cathode and how to set the range?
     
  8. beenthere

    Retired Moderator

    Apr 20, 2004
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    I suggest you obtain the spec sheet. The '07 is set up to drive common anode displays.
     
  9. magikal

    Thread Starter Active Member

    Nov 23, 2008
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    Thanks, I got everything figured out, but my displays have a common cathode. How do I configure the ICL7107 for my purpose?
     
  10. beenthere

    Retired Moderator

    Apr 20, 2004
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    You don't. Either get different 7 segment IC's, or invert the drive signals with something like a couple of CD4049's or some FET's like 2N7000's. Probably cheaper to get other 7 segments.
     
  11. magikal

    Thread Starter Active Member

    Nov 23, 2008
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    Also, I heard that using a battery to power the ICL is not wise because it drains the battery quickly. How long would a one of those 9V batteries last? I am splitting the 9V into -4.5V and 4.5V.
     
  12. magikal

    Thread Starter Active Member

    Nov 23, 2008
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    I've gotten the ICL chip to work when I test each output pin with a voltmeter. However, when I plugged the Seven Segments in, it messes up. Does anybody have an idea as to why?
     
  13. Wendy

    Moderator

    Mar 24, 2008
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    Not without a schematic. Pictures might also be nice.
     
  14. magikal

    Thread Starter Active Member

    Nov 23, 2008
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    I built according to this:
    http://www.electronics-lab.com/projects/test/007/index.html

    Also, I think putting a resistor before the Seven Segments solved the problem, however, the number (displayed voltage) keeps on going up very slowly and the power and ground values decrease.

    Does anybody have any idea why?
     
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