This handy Decade Counter (or sometimes called a Johnson Counter) can be used in many circuits, I will guide you through the basics and show you an example circuit.
Overview
The 4017 IC introduced in 1968 and still popular today, is a 16-pin CMOS Decade Counter which is part of the 4000 series - a family of industry standard integrated circuits which implement a variety of logic functions. They were introduced as a lower power and more versatile alternative to the 7400 series of TTL logic chips.
Pin Configuration
Operation
The 4017 takes clock pulses from the Clock input, and makes one of the ten outputs come on in sequence. Each time a new clock pulse arrives it will go to the next sequential output. If the Reset pin receives a high input the sequence will start again from Output 0 (Pin 3).
If the Enable pin receives a high input it pauses the counter and stops wherever it happens to be when Enable goes HIGH. The ÷10 Output is HIGH for counts 0-4 and LOW for counts 5-9.
Example Circuit
This circuit uses a 555 Timer to generate a continuous square wave pulse which is feed into the Clock input of the 4017 IC. Each time a pulse is received the next sequential output is set to HIGH lighting the LED for that sequence.
Overview
The 4017 IC introduced in 1968 and still popular today, is a 16-pin CMOS Decade Counter which is part of the 4000 series - a family of industry standard integrated circuits which implement a variety of logic functions. They were introduced as a lower power and more versatile alternative to the 7400 series of TTL logic chips.
Pin Configuration
- Pin 01: Output 5 (the 6th sequential output)
- Pin 02: Output 1 (the 2nd sequential output)
- Pin 03: Output 0 (the 1st sequential output)
- Pin 04: Output 2 (the 3th sequential output)
- Pin 05: Output 6 (the 7rd sequential output)
- Pin 06: Output 7 (the 8th sequential output)
- Pin 07: Output 3 (the 4th sequential output)
- Pin 08: Ground (0V Rail)
- Pin 09: Output 8 (the 9th sequential output)
- Pin 10: Output 4 (the 5th sequential output)
- Pin 11: Output 9 (the 10th sequential output)
- Pin 12: ÷10 output (CO)
- Pin 13: Latch enable (LE)
- Pin 14: Clock in (CLK)
- Pin 15: Reset (RST)
- Pin 16: Vcc (voltage between +3V and +15V)
Operation
The 4017 takes clock pulses from the Clock input, and makes one of the ten outputs come on in sequence. Each time a new clock pulse arrives it will go to the next sequential output. If the Reset pin receives a high input the sequence will start again from Output 0 (Pin 3).
If the Enable pin receives a high input it pauses the counter and stops wherever it happens to be when Enable goes HIGH. The ÷10 Output is HIGH for counts 0-4 and LOW for counts 5-9.
Example Circuit
This circuit uses a 555 Timer to generate a continuous square wave pulse which is feed into the Clock input of the 4017 IC. Each time a pulse is received the next sequential output is set to HIGH lighting the LED for that sequence.