This is one my project when I am on Caderization Event in Himpunan Mahasiswa Eleketroteknik (HME). In this project , I make Flip-Flop NIM Tag Digital. According to Videos , You will see that three digits number will be blinking .This system called flip-flop was runned by IC555. This IC called Timer IC. This IC can be used to provided time delays, as an oscillator, and as a flip-flop element. This IC Timer can provide up to four timing circuit in one package.