Our computer's clock is built using several 555 timers. The second is configured as a bistable multivibrator to debounce the toggle switch for selecting between the clock oscillator and manual clock stepping. See https://eater.net/bbcpu8-clock-module for more. Part 1: https://www.youtube.com/watch?v=kRlSFm519Bo Part 2: https://www.youtube.com/watch?v=81BgFhm2vz8 Part 4: https://www.youtube.com/watch?v=SmQ5K7UQPMM Support me on Patreon: https://www.patreon.com/beneater You can get all the components used in this video from any online electronic components distributor for a few dollars. Complete parts list (everything in this video): - Circuit from parts 1 and 2 - 1x 555 timer IC - 2x 1kΩ resistors - 1x 330Ω resistor - 1x 0.01µF capacitor - 1x Double-pole toggle switch - 1x LED - 22 gauge wire