CD4017, 4017 counter pin diagram

Decade counter 4017 | CD4017 Counter


4017 Counter ic Working

CD4017 or HCF4017BE or 74HC4017 is a 16 pin CMOS decade counter/ Divider with 10 decoded output.  This is known as ‘Johnson 10 stage decade counter’.  It has 10 outputs which gives output signal one by one in sequence when a clock signal from the clock input given. When clock input given ,turns on the 10 output in sequence at each time when it receives clock input pulses.

CD4017 is most popular ic which is extremely useful in various applications like Binary counter,Decoder,Decade counter,Frequency division etc . This is more useful in various projects like Light Chaser, Remote controlled Switch, Alarm,Touch ON OFF  switch, Clap switch, Matrix Die.

4017 ic

This IC is also used in electronic industries, automotive industries, manufacturing medical electronic devices, alarms and in electronic instrumentation device.

CD4017, 4017 counter pin diagram4017 pin

Clock pin (pin14)-  This is the input pin which gets the input clock signal from external circuitry. Whenever pin 14 goes high, it provides the output. For first clock pulse pin 3 will provide output; for next pulse pin 2 will provide output and after from pin 4 and so on. After 10 pulse it will again start from Q0 output.

Reset pin (pin 15) – It is used to reset the counter to zero. This is used to reset the IC . The function of this pin is to revert the sequence back to the initial state. When a positive signal or supply voltage applied at this pin, the sequencing comes back to pin 3 and begins the cycle .

If the positive supply is held connected to this pin 15, output goes and holds to the pin 3 (output First) and making this pinout high and fixed.

Therefore to make the IC function Enable, pin 15 should always be connected to ground

4017 counter timing diagram
4017 Timing diagram

.Clock Inhibit pin (pin 13)- It is used to switch the counter “on” and “off”. When we want to switch off the counter, then pin 13 should be high. This pin is used to enable the ic to provide outputs high sequence wise. IC is ON  (Enable )with negative signal on this pin. Pin 13 may be considered as the opposite of pin 14 and this pin out respond to negative peak signals.

In case pin 13 is connected to positive, the whole IC will stops and the outputs will stop sequencing and stop responding to any clock signal applied at pin 14. It will ignore the clock pulse no matter how many times you press the switch meaning the counter will not advance.

Output pin (pin Q0- Q9)- Pin no 1-7 and 9-11 are the output pins . It is used  to receive the output in sequential manner. Like for first pulse pin 3 will provide the output and then pin 2 , then pin 4 and so on. All output pins provide output one by one.

Ground pin (pin 8)- This pin is ground pin and must connected with negative supply.

VCC (pin 16)– It is connected with positive vcc supply

Carry out pin (pin 12)– When we need to connect more than one ic then It is used to connect one or more CD4017 IC’s. The carry pin of first CD4017 is connected to clock input of second and the carry pin of second is connected to the clock input of third and so on.

It is used when we needs to connect two or more ic in cascade. It completes one full cycle for every 10 clock cycles. Next this output is shifted to its next output pin and this sequence continues till the next clock cycle.

By cascading with another 4017 IC, we can count up to 20 numbers. We can increase and increase the range of counting by cascading it with more and more IC 4017s. Each additional cascaded IC will increase the counting range by 10.

One of the best and simple application of this 4017 counter ic is LED Flasher in Sequence wise.

This is the circuit diagram of LED flasher using 4017 which all 10 outputs High (ON) one by one as getting clock signal at pin 14 through the 555 timer ic. At each positive clock pulse output goes to next and previous are off accordingly. By the given below animation diagram it is more clear to understand.

LED sequance flasher chaser using 4017


  • The supply voltage of this IC is 3V to 15V.
  • It is compatible with TTL (Transistor -Transistor Logic).
  • The clock speed or operational speed of  CD4017 IC is 5 MHz.

Also read Touch on off Switch using 4017

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Hi, My name is Aman bharti, I am interested in making and study of Electronics & circuit diagram. I like to share my knowledge and all ideas with people which i get from My Experiment & from different sources. I try to provide any circuit details deeply with test result as possible as. You can contact me on- Email – [email protected]

1 thought on “Decade counter 4017 | CD4017 Counter

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      Hi; I really like your explanation of the CD4017 Decade/Counter. I’m from Canada, and I’m reaaly interested in anything electronics. I’m actually tr4ying to gather informations on a project for my son.He’s building a flying eagle logo sign and want me to install some flashing white leds in sequence. He will need around 100-150 leds. I am thinking of using a 555 timer and some CD4017, and I’m wondering if it is possible to use more than 1 CD4017, since I’ll be using 100-150 leds. Or, is there a simpler way I could do it ??. I would really appreciate if you could give me some advices. Thank you very much.
      Maurice Petit

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