CD4017 is a 16 pin CMOS decade counter/ Divider. It takes clock signal from the clock input and turns on the 10 output in sequence, each time when it receives [[wysiwyg_imageupload::]]clock input pulses. A popular IC, CD4017 is extremely useful in various projects like Light Chaser, Matrix Die. It is also useful in many applications like Binary counter/decoder, frequency division, divide by N counting, Alarm system etc. In order to understand the working of IC CD4017, one must know about its individual pins. It has 3 input pin and 10 output pin and one is ground pin and another is used for power supply and one is Carry out pin.