Using 4017 as a single LED flasher

Discussion in 'General Electronics Chat' started by Fuji, Jan 10, 2015.

  1. Fuji

    Thread Starter Member

    Nov 8, 2014
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    Is the 4017 only limited to making chaser lights or matrix flashing? I can't get a single LED to flash on its own.

    I removed all 9 LED and kept one LED alone and I am not getting a flash from the single LED. Does this mean I have to have more than one LED for the 4017 to enable flashing?
     
    Last edited: Jan 10, 2015
  2. MrChips

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    Oct 2, 2009
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    That circuit as drawn will not work on its own. What is the purpose of Input and S1?
    What signal are you applying to the clock input pin-14?
     
  3. Fuji

    Thread Starter Member

    Nov 8, 2014
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    That is the same question I asked myself. I found this sample from the website it was from. I understand that the 4017 usually works with a 555 timer, but I am trying to exclude the 555 timer because it uses 4/5v to start operating, whereas the 4017 I have starts at a low voltage. There are no 40xx series that would be used on their own is what your saying?
     
  4. MrChips

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    No, no, no.

    CD4017 is a counter. It does not count on its own. It needs something to count, i.e. a circuit that sends out a clocking signal.
    You can create a clock signal with another circuit that can so happen to be a member of the 4000 family.
     
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  5. MrChips

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    If you want a single LED to flash you don't need a 4017. You can do it with a 555 timer circuit. Or you can do it with 4001, 4011, 4106 or an inverting Schmitt trigger circuit. You can also do it with a one or two-transistor circuit.

    Another simple LED flasher is called a Joule Thief that uses one transistor and runs off 1V.
     
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  6. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Some possibilities: TLC555CP, 4049, 40106, 74C14, or 74C914. Add 1 C & 1 R.
     
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  7. Fuji

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    Nov 8, 2014
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    I'll take on with 4001, 4011, and 4106. I just read about 4001. Seems descent.

    I actually tried an LED flash with transistors, but I realized it consumes some power. I tried the single transistor circuit and this I found only works when the current/voltage is high. Never succeeded to light the LED around 2v. Instead of flashing, the LED fades in and then flashes. Looks calm to the eyes too.

    My reason for this is since I have a schematic with no microcontroller, Im figuring out a way to detect low power with another circuit. I'll assume 40xx series would help out for flashing. That LM3909 IC is pretty expensive..and..not found in most places anymore. Too rare of an IC.

    My next schematic will be having a microcontroller, so then I can forget asking these questions and do a little programming. :)
     
    Last edited: Jan 10, 2015
  8. absf

    Senior Member

    Dec 29, 2010
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    Here is a lm3909 emulator using 4 transistors. I use it for fake burglar alarm when I am away from home running at 4.5V - 3x AA battery can last for a month.

    LM3909diy2b.GIF lm3909.PNG

    I have even made a PCB for it. But be ware that I replaced the 2n3904 & 2n3906 with Japanese equivalents.

    Allen
     
    Last edited: Jan 11, 2015
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  9. takao21203

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    Apr 28, 2012
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    why did this IC run into demise?
     
  10. Fuji

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    Nov 8, 2014
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    I ask the same question. They are still being made. On ebay they are being sold around $3 to $5 each. I just don't want to buy an IC that expensive just to flash an LED light.

    I noticed that when certain IC's get obsolete or slowly dissipating from existence, the prices are jacked up when limited amounts are being made. LM3909 looks good for flashing LED's in any circuit to be honest. It reduces the amount of components to use as far as I see it.
     
  11. takao21203

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    these are NOS
     
  12. ScottWang

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    Aug 23, 2012
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    About the CD4017, you can using the reset pin to control the numbers of flashing led, you just connect any one of Q1~Q9 to reset then you can get the different numbers of flashing led.
    The example is here.
     
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  13. Fuji

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    Nov 8, 2014
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    Thank you very much that seems pretty simple to do. I'll take this to consideration.

    I came across auto flashing LED's at around 0.7 seconds. Some go at 1 second/1hz. This will let me cut off half of the components I am using. Now I can just use 2 resistors, 2 zeners and an LED that auto flashes. I guess this is the simplest flashing circuit I have seen so far.

    It seems the auto flashing LED's do have some circuitry inside of them. Not sure how it was made :rolleyes:
     
  14. MrChips

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    What is the simplest LED flasher circuit?

    Here are some possible circuits:

    1) Slow RC flasher

    upload_2015-1-11_12-45-16.png
    2) UJT
    [​IMG]


    3)

    [​IMG]


    4) Tunnel Diode

    5) DIAC
     
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  15. takao21203

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  16. ScottWang

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    Aug 23, 2012
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    The 3) circuit may not work, because it was connected to the wrong pin, the led should be connecting to b not c, and it will be as the function of a zener diode.
     
    Last edited: Jan 11, 2015
  17. MrChips

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    Let's see what Dick Cappels have to say.
     
  18. Fuji

    Thread Starter Member

    Nov 8, 2014
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    I've tried everything posted above a while ago except for the slow RC flasher MrChips posted.


    I ordered auto flashing LED's at 0.7 seconds. So basically a resistor and an LED. Done.
    Isn't this good enough? Im assuming theirs small circuitry in the LED's. :D lol
     
    Last edited: Jan 11, 2015
  19. Fuji

    Thread Starter Member

    Nov 8, 2014
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    Thanks, this is a good post. I actually tried everything before except that Slow RC Flasher. :)
     
  20. Fuji

    Thread Starter Member

    Nov 8, 2014
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