See the full definition for clock in the English Language Learners Dictionary, Thesaurus: All synonyms and antonyms for clock, Nglish: Translation of clock for Spanish Speakers, Britannica English: Translation of clock for Arabic Speakers, Britannica.com: Encyclopedia article about clock. The primary purpose of a clock is to display the time. In 797 (or possibly 801), the Abbasid caliph of Baghdad, Harun al-Rashid, presented Charlemagne with an Asian Elephant named Abul-Abbas together with a "particularly elaborate example" of a water[15] clock. Every computer contains an internal clock that measures the rate a central processing unit (CPU) executes instructions and synchronizes all of the various computer components. A clock is a device that tells the time. The core clock speed can sometimes be changed on newer cards where users want to gain a performance boost. [19] Another Greek clock probably constructed at the time of Alexander was in Gaza, described by Procopius. Over the next 30 years there are mentions of clocks at a number of ecclesiastical institutions in England, Italy, and France. What made you want to look up clock? Some predecessors to the modern clock may be considered as "clocks" that are based on movement in nature: A sundial shows the time by displaying the position of a shadow on a flat surface. Some newer clocks will reset themselves based on radio or Internet time servers that are tuned to national atomic clocks. Appendix A: 24 Hour Clock Time Conversion Table. These early water clocks were calibrated with a sundial. [2] O'clock definition, of, by, or according to the clock (used in specifying the hour of the day): It is now 4 o'clock. An early record of a seconds hand on a clock dates back to about 1560 on a clock now in the Fremersdorf collection. Although it was less accurate than existing quartz clocks, it served to demonstrate the concept. Takes into account all DST clock changes. a central heating system, a VCR, or a time bomb (see: digital counter). In a pendulum clock, the resonator is a pendulum and the gears in the clock keep track of time by counting the resonations (the swingings back and forth) of the pendulum. Spring-driven clocks appeared during the 15th century. Will you be our next winner? [68], Currently, atomic clocks are the most accurate clocks in existence. [73][74] Atomic clocks were first theorized by Lord Kelvin in 1879. 21 Sep. 2015. Frequency is more operations within a given … Although the mechanisms they use vary, all oscillating clocks, mechanical, digital and atomic, work similarly and can be divided into analogous parts. Clock, mechanical or electrical device other than a watch for displaying time. An instrument other than a watch for measuring or indicating time, especially a mechanical or electronic device having a numbered dial and moving hands or a digital display. The name grandfather clock was adopted after the song “Grandfather’s Clock,” written in 1876 by Henry Clay Work, became popular. A “cycle” is technically a pulse synchronized by an internal oscillator, but for our purposes, … Clock definition, an instrument for measuring and recording time, especially by mechanical means, usually with hands or changing numbers to indicate the hour and minute: not designed to be worn or … The clock speed is determined by a quartz-crystal circuit, similar to those used in radio communications equipment. Some have Roman Numerals (I, II, III, etc) instead, or no numbers at all! The only other widely used clock face today is the 24 hour analog dial, because of the use of 24 hour time in military organizations and timetables. Appendix A: 24 Hour Clock Time Conversion Table Use this table to convert conventional AM and … Instead, water clocks in ancient societies were used mainly for astrological reasons. Horological Journal, September 2011, pp. [6] Flip clocks generally do not have electronic mechanisms. George Graham invented the deadbeat escapement for clocks in 1720. Large clocks like this one produce precise time despite their enormous parts and are popular for their aesthetic value. In 1670, William Clement created the anchor escapement,[58] an improvement over Huygens' crown escapement. A major stimulus to improving the accuracy and reliability of clocks was the importance of precise time-keeping for navigation. Spring-driven clocks appeared during the 15th century,[44][45][46] although they are often erroneously credited to Nuremberg watchmaker Peter Henlein (or Henle, or Hele) around 1511. A “cycle” is technically a pulse synchronized by an internal oscillator, but for our purposes, they’re a basic unit that helps understand a CPU’s speed. Completely battery-powered portable versions resembling flashlights are also available. [27][page needed] His astronomical clock and rotating armillary sphere still relied on the use of either flowing water during the spring, summer, autumn seasons and liquid mercury during the freezing temperature of winter (i.e. A CPU with a 300 MHz low-level clock and an 11x multiplier has an effective clock speed of 3.3 GHz. World time and date for cities in all time zones. In Europe, there were the clocks constructed by Richard of Wallingford in St Albans by 1336, and by Giovanni de Dondi in Padua from 1348 to 1364. Simple clocks intended mainly for notification were installed in towers, and did not always require faces or hands. From 1:00 PM to 11:59 PM, add 12 Hours. Clock definition is - a device other than a watch for indicating or measuring time commonly by means of hands moving on a dial; broadly : any periodic system by which time is measured. In Chinese culture, giving a clock (traditional Chinese: 送鐘; simplified Chinese: 送钟; pinyin: sòng zhōng) is often taboo, especially to the elderly as the term for this act is a homophone with the term for the act of attending another's funeral (traditional Chinese: 送終; simplified Chinese: 送终; pinyin: sòngzhōng). The electric clock was patented in 1840, and electronic clocks were introduced in the 20th century, becoming widespread with the development of small battery-powered semiconductor devices. In the chip is a crystal that vibrates at a specific frequency when electricity is … The clock spring winds unique electric conductor tape and is housed in a plastic retainer. The digits are large enough to be easily read, without using glasses, by persons with moderately imperfect vision, so the clocks are convenient for use in their bedrooms. 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