CD4017 IC ek decade counter/divider with 10 decoded outputs hai jo digital electronics aur Arduino/embedded projects mein bohat zyada use hota hai. Ye IC clock pulses ko count karta hai aur sequentially apne 10 outputs (Q0–Q9) par high signal deta hai. Har naya clock pulse aane par agla output active ho jata hai, jabke pehla output low ho jata hai. Is tarah ye IC ek Johnson counter ke tor par kaam karta hai. CD4017 ke andar divide-by-10 counter hota hai jo 10 tak count karke wapas reset ho jata hai. Is IC ka istemal LED chasers, light sequencers, running lights, frequency dividers, siren circuits, aur digital clocks mein hota hai. Iske important pins mein clock input, reset pin, enable pin aur 10 decoded output pins shamil hain. Iska supply voltage 3V se 15V tak hota hai aur ye low power CMOS technology par based hai jo ise energy efficient banati hai.