0 4017 Decade Counter

4017 IC is very useful in led sequencer, led display driver, timer circuitry, inverter driver, and many more applications. This IC has 16 pins with 10 counter outputs (o0,o1 to o9), clock and enable inputs, mater reset (MR), carry out pin,  DC supply and ground pin.

4017 pins:
Pin 1 - output 5
Pin 2 - output 1
Pin 3 - output 0
Pin 4 - output 2
Pin 5 - output 6
Pin 6 - output 7
Pin 7 - output 3
Pin 8 - ground
Pin 9 - output 8
Pin 10 - output 4
Pin 11 - output 9
Pin 12 - carry out pin
Pin 13 - enable input (triggered when signal input is from high to low)
Pin 14 - clock input (triggered when signal input is from low to high)
Pin 15 - Master Reset pin (when it is high, it resets the count)
Pin 16 - DC supply pin

4017 pin function diagram

Above is the timing diagram on when will be the output becomes high based on the clock signal feed to pin 14 ( CP0). From the diagram, when both pin 15 (MR) and pin 13 (CP1) are grounded, all the output pins will be high one after the other. Below is the operation summary of the 4017 IC.

If you planning to extend the counter from the original 10 to more , let say 25 outputs, you can follow the diagram below. You can expand further by adding more IC and following the pattern below.

4017 IC expansion