Readers are advised to proceed with the construction of the presented circuits only after understanding the concepts from the core. Not adhering to this can lead to failures and frustrations.

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Tuesday, December 27, 2011

How to Understand IC 4017 Pin Outs - Explained in Simple Words

The IC 4017 can be considered as one of the most useful and versatile chip having numerous electronic circuit applications. Technically it is called the Johnsons 10 stage decade counter divider.

The name suggest two things, it’s something to do with number 10 and counting/dividing.

The number 10 is connected with the number of outputs this IC has, and these outputs become high in sequence in response to every high clock pulse applied at its input clock pin out. It means, all its 10 outputs will go through one cycle of high output sequencing from start to finish in response to 10 clocks received at its input.

So in a way it is counting and also dividing the input clock by 10 and hence the name.



Let’s understand the pin outs of the IC 4017 in details and from a newcomer’s point of view:

Looking at the figure we see that the device is a 16 pin DIL IC, the pin out numbers are indicated in the diagram with their assignment names.

The pin out which are marked as output are the pins which become logic high one after the other in sequence, meaning the first in the order is 3, so this pin is the one which first becomes high, then it shuts off and simultaneously the next pin #2 becomes, then this pin goes low and simultaneously the preceding pin #4 becomes high and so on until the last pin #11 becomes high and reverts to pin #3 to repeat the cycle.

Please note that the word “high” means a positive voltage that may be equal to the supply voltage of the IC, so when I say the outputs become high in a sequential manner means the outputs produce a positive voltage which shifts in a sequential manner from one output pin to the next, in a “running” DOT manner.

Now the above sequencing or shifting of the output logic from zero to high and back to zero, happens only when a clock signal is applied to the clock input of the IC which is pin #14.

Mind you, if the no clock is applied to this input, it must be assigned either to a positive supply or a negative supply, but should never be kept hanging or unconnected, as per the standard rules for all CMOS inputs.

The clock input pin #14 only responds to positive clocks or a positive signal and with each consequent positive peak signal, the output of the IC shifts or becomes high in sequence, the sequencing of the outputs are in the order of pin outs #3, 2, 4, 7, 10, 1, 5, 6, 9, 11.

Pin #13 may be considered as the opposite of pin #14 and this pin out will respond to negative peak signals, if a clock is applied to this pin, producing the same results with the outputs as discussed above.

 However normally this pin out is never used for applying the clock signals, instead pin #14 is taken as the standard clock input.

However, pin #13 needs to be assigned a ground potential, that means, must be connected to the ground for enabling the IC to function. In case pin #13 is connected to positive, the whole IC will stall and the outputs will stop sequencing and stop responding to any clock signal applied at pin #14.

Pin #15 of the IC is the reset pin input. The function of this pin is to revert the sequence back to the initial state in response to a positive potential or supply voltage, meaning the sequencing comes back to pin #3 and begins the cycle afresh, if a momentary positive supply is applied to pin #15. 

If the positive supply is held connected to this pin #15, again stalls the output from sequencing and the output clamps to pin #3 making this pin-out high and fixed.

Therefore to make the IC function, pin #15 should always be connected to ground. If this pin out is intended to be used as a reset input, then it may be clamped to ground with a series resistor of 100K or any other high value, so that a positive supply now can be freely introduced to it, whenever the IC is required to be reset.

Pin #8 is the ground pin and must be connected to the negative of the supply, while pin #16 is the positive and should be terminated to the positive of the voltage supply.

Pin #12 is the carry out, and is irrelevant unless many ICs are connected in series, we will discuss it some other day. Pin #12 can be left open.

Any questions….:-)

30 comments:

  1. for which purpose IC 4017 is used .


    thank u..

    ReplyDelete
    Replies
    1. It depends on the user how he wants to use it...basically it is used for generating sequencing output pulse and for generating decorative LED light patterns, it is also used in timer applications.

      Delete
  2. really you have a fantastic blog ^_^
    thank you so much :)

    ReplyDelete
  3. Hi Swagatam,

    can you make a diagram to check if this IC 4017 is working?

    for testing purposes only of the IC.

    Thanks in advance.

    Regards,

    ReplyDelete
    Replies
    1. You will have to make a 16 pin socket arrangement with the relevant pins assigned to the appropriate positions, and LeDs fixed at the output pins.

      The circuit should have an oscillator stage also for feeding pin#14 of the socket.

      Then we just need to insert the IC into the socket, press the oscillator button, and check the led sequencing. This will confirm the IC working.

      Regards.

      Delete
    2. Hi Swagatam,

      can i use 555 as a oscillator?

      Regards,

      Delete
    3. Hi Swagatam,

      thanks a lot for your quick response.

      just to clarify the connection of IC 4017:

      pin# 16 = positive
      pin# 8 = negative (ground)
      pin# 14 = connected to pin# 3 of IC 555
      pin# 13 = ?
      ten output = LED's



      Regards,

      Delete
    4. That's perfect!

      pin#13, pin#15 = ground

      ten outputs = LEDs with 1K series resistor for each led to ground.

      Delete
    5. sorry, correction:

      ten outputs = LEDs with their free ends (cathodes) made common and terminated to ground via a single 1K resistor.....

      Delete
    6. 555 oscillator will be great!

      Delete
    7. Thanks a lot Swagatam...

      i already made one, its like a toggle switch but i use a solenoid for locking and unlocking my gate.

      this blogs of your is very helpful. i also made one of your circuit a automatic voltage stabilizer for appliances.

      keep up the good work :)

      more power to you!!!

      Regards,

      Delete
  4. can you explain pin#12, carry out pin...what is the purpose of it?

    ReplyDelete
  5. pin#12 is for supplying and forwarding the clock pulses to the following ICs if there are any....

    ReplyDelete
  6. Hi Bro Swagatam, just curious to know if the 4017 can be made to count down as in shifts from high (#11) to (#3)without placing the led to look like its counting down arrangement? Or is there any other similar IC for this not a uController? Thanks I think you can provide me the answer to this question. Thanks bro swagatam.

    ReplyDelete
  7. Sorry Bro, just stumbled upon your other post http://homemadecircuitsandschematics.blogspot.com/2011/12/simple-reverse-forward-led-light-chaser.html :P Thanks again. great post and nice explanations Bro Swagatam.

    ReplyDelete
  8. I am attending ITT tech for an electronics degree and I came up on a request the other day to build a circuit that can count down the days till christmas... could the 4017 ic possibly do this?

    ReplyDelete
    Replies
    1. You may have to incorporate three ICs, 4060, 4040 and also 4017 for acquiring precise results....

      Delete
  9. I'm working in electronics workbench in school and it doesn't have 4017, can i change it with some other IC?

    ReplyDelete
  10. I want to know why led at pin 2 is on and pin is of for checking?

    ReplyDelete
  11. Sir plz contact me.09990333434,9991333434,9992333434. My email id. babaledboard@gmail.com

    ReplyDelete
  12. sir,my name is karthie...i need to know where where this was used...?

    ReplyDelete
    Replies
    1. Hi Karthik, one example can be seen in light chaser circuits, just type "light chaser" in the search box above, you will find the related articles.

      Delete
  13. Hi I am going to be using this IC in the LED dice with slow down project and I'm looking to connect a sound generator circuit with a flip flop to produce a sound when the LED's come to a stop. I wanted to know what pin on the 4017 will have a positive output once the LED sequence has come to a stop? Hence so I can connect the input of the second circuit (the flip flop) to that pin.

    ReplyDelete
    Replies
    1. The output will be random and never fixed to a definite pin. It will depend on how many clocks are applied at pin14 of the IC. It will begin from pin3 and sequence by one pinout in response to every positive pulse at its pin14, as soon as it reaches pin11, the sequence returns back to pin3 for repeating the cycle.

      Delete
  14. Hi I'm making a dice circuit with a cd4017 and a 555timer but I can't get the LEDs that are connected to different outputs on the 4017 to light at the same time. For example, I connected four corners together to make 4, and two middle to make two, but I don't know how to make them both light to make six! It seems like the cd4017 can only have high output on one pin at once? Anything will help, thank you

    ReplyDelete
    Replies
    1. You can use scrs at the output of the 4017 for latching the switched pinouts of the IC, please refer to the first diagram in this article:

      http://homemadecircuitsandschematics.blogspot.in/2013/03/sequential-bar-graph-turn-light.html

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