Need Help on Traffic signal circuit.....

Discussion in 'The Projects Forum' started by Sarmad Zaheer, May 4, 2015.

  1. Sarmad Zaheer

    Thread Starter New Member

    May 4, 2015
    5
    0
    Can anybody tell me what is wrong with this circuit??
    i can only use 555 IC.
    I can also upload .pdsprj file for proteus???
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,965
    744
    whats wrong with it, what is it not doing, it looks like two astables ,one is feeding the other led flasher...
     
  3. Reloadron

    Active Member

    Jan 15, 2015
    963
    232
    Would this be homework or schoolwork? Should that be the case this should be in the homework / schoolwork sections of the forums. Your circuit is just a copy and paste of this circuit which has been around a long time. Why do you believe something is wrong with it? I assume you have built the circuit but you fail to mention what the circuit does or does not do? If wired like the link the circuit should work.

    Oh yeah, your battery symbol is drawn backwards. Long line is + and short line is -.

    Ron
     
  4. Sarmad Zaheer

    Thread Starter New Member

    May 4, 2015
    5
    0
    hey Ron! this is my final project for DLD(digital logic design). Our goal is to create a traffic signal without using any IC except 555 timer.
     
  5. Sarmad Zaheer

    Thread Starter New Member

    May 4, 2015
    5
    0
    it just turns on yellow for a moment then green. it never turns on red
     
  6. Sarmad Zaheer

    Thread Starter New Member

    May 4, 2015
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    i am trying to follow this picture but i am confused by the parts encircled in red??are they overlapping or connected??
     
  7. Reloadron

    Active Member

    Jan 15, 2015
    963
    232
    Well, on both chips pins 4 & 8 are tied together and go to +12 Volts. Here is what I suggest you do. Take a look at the 555 Data Sheet and gain an understanding of what each 555 is doing in this circuit. Normally on a good drawing the connects are shown by using a dot, for example:

    Connect No Connect.png

    Your original drawing reflects the dots.

    Ron
     
  8. Sarmad Zaheer

    Thread Starter New Member

    May 4, 2015
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    0
    But that,s the problem. I didn't even know about the 555 IC before researching about it. my instructor is refusing to tell us anything about it
     
  9. Reloadron

    Active Member

    Jan 15, 2015
    963
    232
    The 555 Timer:

    The 555 Timer Data Sheet.

    While I have no idea why your instructor refuses to tell you anything about the 555 it is among the oldest integrated circuits out there and is a very versatile IC. Maybe your instructor expects you to learn about the chip on your own studying the chip. There are volumes of text and circuits using the 555 Timer IC, more than could be covered in a single thread in this forum. For your traffic light or better put the traffic light circuit it is a matter of understanding the chip and seeing how the chip is applied. Regarding the design you posted:

    Note the second 555 and how the first 555 can remove power from it.

    Ron
     
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