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An analog pendulum clock made around 18th century. A clock or chronometer is a device that measures and displays time.The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month, and the year.
The same timeline seems to apply in Europe, where mechanical escapements were used in clocks by that time. Up to the 15th century, clockwork was driven by water, weights, or other roundabout, relatively primitive means, but in 1430 a clock was presented to Philip the Good, Duke of Burgundy, that was driven by a spring. This became a standard ...
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. Most digital clocks display the hour of the day in 24-hour format; in the United States and a few other countries, a commonly used hour sequence option is 12-hour format (with some indication of AM or PM).
A pendulum clock is a clock that uses a pendulum, a swinging weight, as its timekeeping element. The advantage of a pendulum for timekeeping is that it is an approximate harmonic oscillator: It swings back and forth in a precise time interval dependent on its length, and resists swinging at other rates.
The elephant clock in a manuscript by Al-Jazari (1206 AD) from The Book of Knowledge of Ingenious Mechanical Devices. [1] The elephant clock was a model of water clock invented by the medieval Islamic engineer Ismail al-Jazari (1136–1206). Its design was detailed in his book, The Book of Knowledge of Ingenious Mechanical Devices.
Cuckoo clock, a so-called Jagdstück ("hunt piece"), Black Forest, c. 1900, Deutsches Uhrenmuseum, Inv. 2006-013. A cuckoo clock is a type of clock, not typically pendulum driven, that strikes the hours with a sound like a common cuckoo call and has an automated cuckoo bird that moves with each note. Some move their wings and open and close ...
Al-Jazari's candle clock. Al-Jazari described a candle clock in 1206. [4] It included a dial to display the time and, for the first time, employed a bayonet fitting, a fastening mechanism still used in modern times. [5] The English engineer and historian Donald Routledge Hill described one of al-Jazari's candle clocks as follows:
A timer or countdown timer is a type of clock that starts from a specified time duration and stops upon reaching 00:00. An example of a simple timer is an hourglass. Commonly, a timer triggers an alarm when it ends. A timer can be implemented through hardware or software.