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CD4017 IC

CD4017 Pin Configuration

Pin Number

Pin Name


1 to 7 and 9,10,11

Output pins Q0 to Q9

These are the 10 output pins on which the counting occurs, they are not in order hence verify pin diagram above


Vss or Ground

Connected to the Ground of the circuit


Carry Out (CO)

This pin goes high after the IC counts from 1 to 10. This is used as carry while counting.


Clock Enable (EN)

This is an input which when made high will hold the count at the current state



The counting happens when this clock pulse goes high , this pin is normally connected to 555 timer or other uC to produce a pulse



As the name suggests this pin resets the count back to 1


Vdd / Vcc

Connects to the supply voltage typically +5V



  • High speed 16 pin CMOS Decade counter
  • Supports 10 decoded outputs
  • Wide supply voltage range from 3V to 15V, typically +5V
  • TTL compatible
  • Maximum Clock Frequency: 5.5Mhz
  • Available in 16-pin PDIP, GDIP, PDSO packages


Note: Complete Technical Details can be found in the CD4017 datasheet given at the end of this page.


CD4017 Equivalent Counters

IC4040, IC4060, IC4022


Where to use CD4017 IC

The IC CD4017 is used for counting applications, it has the capability to turn on 10 outputs sequentially in a pre-defined time and reset the count or hold it when required. It also has the capability to indicate the status of counting using Carry pin. This is commonly used for Led chasers and other logical output projects, so if you are looking for an sequential decoded counting IC that can count up to 10 then this IC will be your right choice


How to use a CD4017 IC

The IC can work from 3V to 15V, but normally powered with +5V to the Vdd/Vcc pin and the Ground/Vss pin is connected to ground. We have 10 output pins ranging from Q0 to Q9, these pins can be connected to any load but we are using LEDs here as shown in the circuit below.

CD4017 Circuit Diagram

This IC will increment the count from 0 to 9 (Q0 to Q9) each time it senses a high pulse from the clock pin (pin 14). So we need a clock source to keep this IC ticking, this clock source can be a simple Timer circuit that could generate pulse or a microcontroller like Arduino, PIC, etc. to generate our custom pulse using I/O pins.

The output changes sequentially from Q0 to Q9 for every high pulse from the Clock pin, but this sequence can be interrupted by two pins. They are the Clock Enable (pin 13) and Reset (pin 15) pins. These pins are held low (0V/grounded) by default, but when the Clock Enable pin is made high the counting pauses. For example if the count was at pin Q3 when the Clock enable pin was made high, then the count will pause at pin Q3 irrespective of any high pulses from clock and will continue incrementing only when Clock Enable is made low again. Similarly, if the reset pin is made high. The count will reset itself back to Q0 and will stay there until Q0 is made low again.

We have another pin called the carry out pin (12th pin), this pin will stay low (0V) by default. But when the IC completes counting up to 10, the pin will go high and will remain high till it counts till 5, when its 5 it will go down (0V) and turn on again when it reaches 10. The timing diagram of the IC indicating the state of Output pins and Carry pin for every high pulse signal is shown below.

Output pins state



  • Used in LED matrix, LED chaser and other LED projects
  • Binary counter or Binary decoder
  • Can be used for divide by N counting
  • Remote metering, automotive, medical electronics


2D Model of CD4017 (PDIP)

CD4017 Dimensions

CD4017 Pins Dimensions

Component Datasheet

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