Hello friends! Today, we will build a traffic-signal demonstration using a 555 timer and a CD4017 counter in Proteus ISIS. The timer supplies a repeating clock, the counter advances through ten states, and a few diodes combine those states into red, yellow and green indications. This is a useful introduction to sequencing without a microcontroller. We will keep the original project's teaching flow, but make the timing and output connections more precise. In particular, the CD4017 is a decade counter with decoded outputs, not a serial-data shift register. Its clock input advances a sequence; it does not receive a stream of data bits describing the lamp colors. Our goal is a small educational display. We will calculate the state duration, explain the overlap between red and yellow, and ident ...