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[HELP 4 WAY- TRAFFIC LIGHT] Can someone tell me what is wrong with our schematic?

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by Frostyflame, May 1, 2017.

  1. Frostyflame

    Frostyflame New Member

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    When we run it through the Circuit wizard it goes without errors but when we imply it on a breadboard it is stuck on "4", it doesn't countdown.
     

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  2. crutschow

    crutschow Well-Known Member Most Helpful Member

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    Then there is likely a wiring error on the breadboard.
     
  3. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Where are your current limiting resistors? Also, your 555 timer astable multivibrator circuit is wrong.
     
  4. dave

    Dave New Member

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  5. Pommie

    Pommie Well-Known Member Most Helpful Member

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    That's an interesting name for a traffic light - at the top of the diagrams.

    Mike.
     
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  6. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Cmos logic IC inputs must never be floating. Your CD4017 IC has its EN and R inputs floating. They MUST be at a certain logic level.
    I agree that you did not read the datasheet for the CD4511 and have probably destroyed it by missing the output current-limiting resistors.

    The CD4511 is designed to drive ONE display but your circuit has four displays in parallel. The LEDs in the different displays do not match so some will be very dim or will not light. Why not use a CD4511 with current-limiting resistors for each display?
     
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  7. Cicero

    Cicero Active Member

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    Hahaha, students will be students.
     
  8. schmitt trigger

    schmitt trigger Active Member

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    The discrete LEDs are also lacking limiting resistors.

    Plus...they are wired, or at least drawn, in a completely confusing, messy and absurd way.
     
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