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Circuit that takes a pulse from a 555 chip

  1. Nov 17, 2004 #1
    We currenlty have a circuit that takes a pulse from a 555 chip and goes through two divide by ten 7490 switchs to create a binary counter that counts up to ten. We are trying to figure out how to convert this binary which we have displayed in regular leds into a 7 segment LED - (LN514rk)

    any help would be great.
     
  2. jcsd
  3. Nov 17, 2004 #2
    Don't remember the number but there is a seven segment driver made specifically for this. If you cant find this, set it up using gates to get 10 separate outputs and then diode or those to drive the 7 segment display.
     
  4. Nov 17, 2004 #3

    dduardo

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    You'll need to convert the binary number into BCD and then use a 7447 to convert BCD to 7 segment.

    The easy way to convert binary to BCD is to find a 74185 but it has been discontinued. If you can't find that chip you can always program a ROM to do the conversion.
     
  5. Nov 17, 2004 #4

    NoTime

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    You could set up the 7490 to do a carry-reset on A(hex).
     
  6. Nov 18, 2004 #5
    How would we set up the 7490 to do a carry-reset on A(hex)?
     
  7. Nov 18, 2004 #6
    So the 7446 isn't the way to go on this circuit? We were debating between it and the 7447
     
  8. Nov 18, 2004 #7
    Alright So what would I need to do if I can't find the 74185 circuit--- Right now again I have a 555 going to two 7490 integratded divide by 10 circuits--- and then I have access to 7447 and 7446 chips is there anything I can do with those to hook up to a 7 segment LED (LN514rk).
     
  9. Nov 18, 2004 #8

    NoTime

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    Use an AND gate or two. There are a few ways to wire this, depending on the specific behavior you want.

    The 7447 should be ok. IIRC the 46 takes a higher output.
    The two numbers are much the same. Look up the specs.
     
  10. Nov 18, 2004 #9
    BTW, is this counting 0-9 or 1-10?
     
  11. Nov 18, 2004 #10

    GENIERE

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    You can display a "10" on the 7 bit display if you mentally rotate it. A 0 to 11 sequence is possible. I learned this by laying down on the job.:biggrin:


    ..
     
  12. Nov 18, 2004 #11

    NoTime

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    Laying down on the job :rofl: :rofl: :rofl:
    10 can be just about any value you can imagine.
    Depends on the base you select. :biggrin:
     
  13. Nov 18, 2004 #12
    ok i just now got acess to a 4511 integradted circuit so I am trying to figure out how to use it...
     
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