The digital clock is perhaps the most common and also most overlooked gadgets in homes today. Once cutting-edge technology, the digital clock has become so familiar an object that its place in a home is almost comforting. Almost everyone has had an experience with a digital alarm-clock. The components are basically standard across all models, with the technology undergoing very little change in the past 20 years.
The Hamilton Watch Co. introduced the standard LED display that comes in most digital clocks in 1972. The display had already become famous from its appearance in the futuristic space movie "2001: A Space Odyssey" after Hamilton lent the film makers an early prototype. LED stands for "Light Emitting Diode." LED's are basically small light bulbs filled with a special metallic formula that will not burn out like a normal filament.
The major innovation involved in the creation of the modern digital clock was the quartz oscillator. Using a quartz crystal, a digital clock is able to keep much more accurate time than is possible with the traditional clock. The quartz crystal resonates with a constant rhythm of 60 hertz that can be used to keep time. Cheaper digital clocks also sometimes use the oscillation in a power cord, which is only somewhat less accurate than quartz.
Every digital clock has a counter that converts the signal from the oscillating quartz or power signal into a digital number. By understanding each pulse as one second, the counter goes up to a different number depending on which clock, and then cycles back to begin a new minute. A basic microchip usually further converts the counters number into a typical time signature, which is sent to the LED display.