Interesting facts:
• Digital clocks typically use the 50 or 60 hertz oscillation of AC power or a 32,768 hertz crystal oscillator as in a quartz clock to keep time.
• In 1972, Hamilton Watch Co of Lancaster, Pennsylvania, produced the first watch with a digital display. They had hinted that they had a new breakthrough as early as 1970 but had two years of teething problems before its 18-carat gold Pulsar hit the world at a price of $2,100.
• The biggest digital clock is the Lichtzeitpegel ("Light Time Level") on the television tower Rheinturm Düsseldorf, Germany.