The CD 4017 is called a COUNTER or DIVIDER
or DECADE COUNTER. It is a very handy chip for producing "Running
LED effects" etc.
It has 10 outputs. Output "0" goes HIGH on the rise of the first
On the rise of the second clock cycle, output "0" goes LOW and output "1"
goes HIGH. This process continues across the ten outputs and cycles to
output "0" on the eleventh cycle.
The "Carry Out" pin goes LOW when output "5" goes HIGH and goes
HIGH when output "0" goes HIGH.
When RESET (pin 15) is taken HIGH, the chip will make output "0"
go HIGH and remain HIGH.
When "Clock Inhibit" (pin 13) is taken HIGH, the counter
will FREEZE on the output that is currently HIGH.
4017 is a divide-by-10 CMOS chip.
Minimum supply voltage 6v
Maximum supply voltage 15v
Max current per output 15mA
Maximum speed of operation 5MHz
The animation below shows how a CD 4017 works. It will count every time
the voltage at pin 14 swings from low to high, provided pin 13 is low
and pin 15 is not high. Click the power switch to start the action!
You can click the Enable line to see what happens and the
Circuits built around a CD 4017:
SCANNER circuit above illuminates one of the ten LEDs at a time.
KITT SCANNER scans back and forth across the 6 LEDs.