cd4017 decade counter and 555 astable

Thread Starter


Joined Oct 14, 2008
Hi everyone,
Iam designing a small project regarding induction motor speed control.
As a part of it, Iam using 4017 decade counter to cahnge the firing angle of triac.Iam not understanding the pins Cout(12), CE (13) & reset(15) of 4017.

in detail....
My requirements are,
1. I need to use the ten outputs of 4017.
2. the outputs should be cyclic i.e., after the 10th count it should again restart from 1.
3. the input pulses must be given from a 555 astable.
4. I need both ON period & OFF period should be 1 second. (T=2 sec)
5. somewhere i read, that not to use electrolytic capacitors as time constant element for 555. I need the RC values.

The operating voltage is 9v.



Joined Aug 7, 2008
For a free-running 4017: ground pins 15,13, 8. pin 12 open[carry ],clock ,rising edge on pin 14. Now the questions: do you need on and off period for each of ten counts,like a ten phase clock?,like a divide by two on each output? For one sec, clock, 1.5μF and 1M pot.