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Need your help with 7 segment display using 4026 and NE555

  1. Jun 5, 2017 #1
    • Member advised to use the homework template for posts in the homework sections of PF.
    Hello,
    I have to make a circuit using IC4026 and 555 timer with 3 switches : one that pauses the counting, one that hides it and one that resets it. I'm having problems with the last two.
    I have joined a picture of my circuit on proteus isis.
    I'll be very grateful if you could help me.
     

    Attached Files:

  2. jcsd
  3. Jun 5, 2017 #2

    mfb

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    What did you try so far, where did you get stuck?

    The IC should have some data sheet explaining how to reset the counter.
     
  4. Jun 5, 2017 #3
    I modified the circuit, now I can pause and reset the counting.
    what I would like to do is hide it when you push a button but still counts until you let go of the button
     

    Attached Files:

    Last edited: Jun 5, 2017
  5. Jun 5, 2017 #4
    I changed the circuit, now I can reset and pause the citcuit .
    What I would like to do is hide the count when I push a button while it still goes on until I let go of the button then the display is on again.
    thank you for your help.
     

    Attached Files:

  6. Jun 5, 2017 #5

    Janus

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    That's what pin 3 DEI(display enable input) is for. A low at this input turns off the display output.
     
  7. Jun 5, 2017 #6
    hello jamus,
    I tried doing that by shorting the supply to ground but I get yellow squares does that mean that there is an error ?
     

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  8. Jun 5, 2017 #7

    mfb

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    Why do you want to create a short circuit between power supply and ground?
    Potentially damaging your power supply should give an error, indeed.
    What does that have to do with the DEI input?
     
  9. Jun 5, 2017 #8

    Janus

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    Why would you try pulling the supply to ground? You only need to pull pin three to ground.(without effecting the rest of the circuit).
     
  10. Jun 5, 2017 #9
    Yes you are right.
    Thank you.
     
  11. Jun 5, 2017 #10
    I added a switch between pin 3 U2 and the supply.
    So the display is on when the we push the switch and it is off when youlet go of the switch.
    Is there any way without using logic gate NOT to have it display normaly and to turn off the display output when we push the button ?
     

    Attached Files:

  12. Jun 5, 2017 #11

    Janus

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    Connect a resistor between supply and pin three and your switch between pin three and ground. With the button released, the pin is pulled high. When the button is pushed, it is pulled low, but the resistor prevents the supply from being shorted.
     
  13. Jun 5, 2017 #12
    Thank you very much Janus !
     
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