In the previous episode, Karen did an overview of integrated circuits or ICs. This week, Karen chose an electronics kit that contains two ICs, a phase locked loop, and a ripple binary counter. A phase-locked loop takes one external input and one internal input, comparing the frequencies of their signal and turns that difference into a voltage that goes back to adjust the internal signal. This process continues until both external and internal signals are equal. This process generates an output signal that slowly changes then stabilizes. In today’s kit, an electronic dice kit, that signal from the phase-locked loop IC is used as the clock input signal of the second IC, the binary counter.