Most electronics designers have a favourite IC they’ve grown to love over the years. Some will have a fondness for the class 741 op-amp, some for the handiness of the adjustable LM317 regulator – good for up to 1.5A. Some wax lyrical about the ubiquitous 555 timer. I’m quite partial to MAXIM’s MAX1496 ADC with 3-digit display.
Anyway, enough of that. This design is limited to one special IC in a cast of thousands – the 4017 Johnson Counter.