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cd4017-decade-counter

4 min read

Important Note

This entire repo was AI created - including all of the data within. The intent was to A) help me with my personal electronics inventory; and B) see how I could use AI to make that process a bit easier. DO NOT TRUST!

CD4017 - CMOS Decade Counter/Divider

Details

  • Location: Cabinet-3, Bin 33, Section H
  • Category: Logic ICs
  • Brand: Various (TI, STMicroelectronics, etc.)
  • Part Number: CD4017 / CD4017BE
  • Package: 16-DIP
  • Quantity: 2
  • Status: Available
  • Price Range: $0.75-1.50
  • Datasheet: CD4017B Datasheet
  • Product URL: https://www.ti.com/product/CD4017B

Description

The CD4017 is a CMOS Johnson decade counter with 10 decoded outputs. It advances through a sequence of 10 states (0-9) on each positive clock edge, with only one output being HIGH at any given time while all others remain LOW. After reaching the 9th state, it automatically resets to the 0th state on the next clock pulse. This makes it ideal for sequential LED displays, frequency division, and various timing applications where a repeating 10-step sequence is needed.

Specifications

Electrical Characteristics

  • Operating Voltage: 3V ~ 15V (wide voltage range)
  • Supply Current: Very low (µA range in static conditions)
  • Output Current: 10-20mA per output (typical)
  • Clock Frequency: DC to several MHz
  • Propagation Delay: ~100ns @ 10V, ~200ns @ 5V
  • Input Threshold: 0.3 × VDD (LOW), 0.7 × VDD (HIGH)

Physical Characteristics

  • Package: 16-DIP (Dual In-line Package)
  • Dimensions: 0.600” (15.24mm) width
  • Pin Pitch: 0.100” (2.54mm)
  • Operating Temperature: -55°C to +125°C

Key Features

  • Johnson decade counter (divide-by-10)
  • 10 decoded outputs (Q0-Q9)
  • Asynchronous reset capability
  • Wide operating voltage range
  • Low power CMOS technology
  • TTL compatible inputs and outputs

Pinout Diagram

    CD4017 16-Pin DIP
    ┌─────────────────┐
Q5  │1             16│ VDD
Q1  │2             15│ RESET
Q0  │3             14│ CLOCK
Q2  │4             13│ CLOCK ENABLE
Q6  │5             12│ CARRY OUT
Q7  │6             11│ Q9
Q3  │7             10│ Q4
VSS │8              9│ Q8
    └─────────────────┘

Pin Descriptions

PinNameDescription
1Q5Output 5
2Q1Output 1
3Q0Output 0 (initial state)
4Q2Output 2
5Q6Output 6
6Q7Output 7
7Q3Output 3
8VSSGround (0V)
9Q8Output 8
10Q4Output 4
11Q9Output 9
12CARRY OUTGoes HIGH during Q5-Q9 states
13CLOCK ENABLEEnable/disable clock (active LOW)
14CLOCKClock input (positive edge triggered)
15RESETAsynchronous reset (active HIGH)
16VDDPositive power supply

Operation Sequence

Count Sequence (Q0 through Q9):

Clock PulseActive OutputState
0 (Reset)Q00
1Q11
2Q22
3Q33
4Q44
5Q55
6Q66
7Q77
8Q88
9Q99
10Q00 (repeats)

Applications

Common use cases for the CD4017:

  • LED chasers and sequencers (Knight Rider effects)
  • Frequency dividers (divide by 10)
  • Digital counters and displays
  • Sequential control systems
  • State machines and timing circuits
  • Sound and light show controllers
  • Educational electronics projects
  • Cascaded counting systems

Circuit Examples

Basic LED Chaser Circuit

555 Timer ---- Clock (Pin 14)
VDD ---- Reset (Pin 15) via 10kΩ resistor
GND ---- Clock Enable (Pin 13)
Each Q output ---- LED + Current Limiting Resistor ---- GND

Frequency Divider

Input Signal ---- Clock (Pin 14)
Carry Out (Pin 12) ---- Output (1/10 frequency)
VDD ---- Reset (Pin 15) via 10kΩ resistor
GND ---- Clock Enable (Pin 13)

Cascaded Counter (Count to 100)

CD4017 #1 Carry Out ---- CD4017 #2 Clock Input
Common VDD, GND, and Reset connections
Provides 100 unique states (10 × 10)

Programming Examples

Arduino Control Example

#define CLOCK_PIN 2
#define RESET_PIN 3
 
void setup() {
  pinMode(CLOCK_PIN, OUTPUT);
  pinMode(RESET_PIN, OUTPUT);
  
  // Reset the counter
  digitalWrite(RESET_PIN, HIGH);
  delay(1);
  digitalWrite(RESET_PIN, LOW);
}
 
void loop() {
  // Generate clock pulses
  digitalWrite(CLOCK_PIN, HIGH);
  delay(500);
  digitalWrite(CLOCK_PIN, LOW);
  delay(500);
}

Variable Speed Sequencer

int speed = 100; // milliseconds between steps
 
void loop() {
  digitalWrite(CLOCK_PIN, HIGH);
  delayMicroseconds(10); // Short pulse
  digitalWrite(CLOCK_PIN, LOW);
  delay(speed);
  
  // Vary speed based on potentiometer
  speed = analogRead(A0);
}

Technical Notes

Important considerations for the CD4017:

  • Reset on Power-up: Always include reset circuitry for predictable startup
  • Clock Enable: Tie to GND for normal operation, or use for gating
  • Carry Out: Useful for cascading multiple CD4017s
  • Output Current: Use current limiting resistors for LED loads
  • Decoupling: Use 0.1µF capacitor between VDD and VSS
  • Clock Signal: Ensure clean clock edges for reliable operation

Tags

counter-ic, decade-counter, sequencer, cmos, cd4017, johnson-counter cabinet-3 bin-33 status-available

Notes

The CD4017 is one of the most popular and versatile counter ICs in electronics. Having 2 of these chips provides excellent flexibility for creating sequential displays, frequency dividers, and timing circuits. The wide voltage range (3V-15V) makes them compatible with both 5V and higher voltage systems. They’re perfect for learning digital logic concepts, creating visual effects with LEDs, and building timing circuits. The Johnson counter architecture ensures that only one output is active at a time, making it ideal for multiplexing applications and sequential control systems. These ICs are excellent for both educational projects and practical applications where reliable sequential operation is needed.

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