443:
electromechanical clocks the electricity serves no time keeping function. The timekeeping function is regulated by the pendulum. Near the end of the nineteenth century, the availability of the dry cell battery made it practical to use electric power in clocks. The use of electricity then led to many variations of clock and motor designs. Electromechanical clocks were made as individual timepieces but most commonly were used as integral parts of synchronized time installations. Experience in telegraphy led to connecting remote clocks (slave clocks) via wires to a controlling (master clock) clock. The goal was to create a clock system where each clock displayed exactly the same time. The master and the slaves are electromechanical clocks. The
435:
284:. They use modern low-voltage DC-powered circuitry, which may be supplied by a battery or derived from mains electricity. They are the most common type of clock today. Quartz clocks and watches as supplied by the manufacturer typically keep time with an error of a few seconds per week, although sometimes more. Inexpensive quartz movements are often specified to keep time within 30 seconds per month (1 second per day, 6 minutes per year). Lower error can be achieved by individual calibration if adjustment is possible, subject to the stability of the oscillator, particularly with change in temperature. Higher accuracy is possible at higher cost.
122:
469:
614:
411:, where he developed an electric clock to have the Hipp-Toggle, presented in Berlin at an exhibition in 1843. The Hipp-Toggle is a device attached to a pendulum or balance wheel that electro-mechanically allows occasional impulse or drive to the pendulum or wheel as its amplitude of swing drops below a certain level, and is so efficient that it was subsequently used in electric clocks for over a hundred years. Hipp also invented a small motor and built the chronoscope and the registering
166:
2208:
25:
629:(FERC) to eliminate the TEC. While this would have freed the power companies from the threat of fines and also provided an extremely modest increase in frequency stability, it was also noted that synchronous clocks, which include wall clocks, alarm clocks, and other clocks computing the time on the basis of their electrical power, would accumulate several minutes of error between the semi-annual resets for
329:
2218:
522:
321:
637:(NAESB), a non-governmental organization that is business-oriented, for removing that standard. If the FERC adopts the NAESB petition, TECs will no longer be utilized in the United States and Canada, and clocks timed by them will likely wander uncontrolled until manually reset, however as of 2021 WEQ-006 was still in place. It was noted in a technical paper by employees of the
557:; 60 cycles per second (Hz) in North America and parts of South America, 50 cycles per second in most other countries. The gear train scales this rotation so the minute hand rotates once per hour. Thus the synchronous clock can be regarded as not so much a timekeeper as a mechanical counter, whose hands display a running count of the number of cycles of alternating current.
222:, which was wound up more frequently by an electric motor or electromagnet. This mechanism was more accurate than a mainspring, because the frequent winding averaged out variations in the clock's rate caused by the varying force of the spring as it unwound. It was used in precision pendulum clocks, and in automotive clocks until the 1970s.
379:, a Scottish clock and instrument maker was the first to invent and patent a clock powered by electric current. His original electric clock patent is dated October 10, 1840. On January 11, 1841, Alexander Bain along with John Barwise, a chronometer maker, took out another important patent describing a clock in which an
452:
slave clocks. The slave clocks are connected by wires to the master clock. These systems are found in locations where multiple clocks would be used such as learning institutions, businesses, factories, transportation networks, banks, offices and government facilities. A notable example of this type of system is the
633:. This consequence was reported in the American news media, and the initiative was dropped. However, in late 2016 a similar proposal was again filed by the NERC to the FERC, which was approved two months later. It is contingent upon the removal of the standard WEQ-006, and the NERC also petitioned the
371:
batteries and an oscillating orb. His team produced improved clocks over many years, which were later denoted as "the most elegant and at the same time the most simple movement yet produced by the electric column". Zamboni's clock had a vertical needle supported by a pivot and was so energy efficient
271:
keep time by counting the oscillations of a calibrated tuning fork with a specific frequency. These were only made in battery-powered form. Battery-powered clocks have been made using the schemes above with the obvious exception of a synchronous movement. All battery-powered clocks have been largely
451:
mechanism is not a conventional clock mechanism as it consists only of a ratchet wheel and time train. Slave clocks rely upon electrical impulses from the master clock to mechanically move the clock hands one unit of time. Synchronized time systems are made up of one master clock and any number of
605:
atomic clock time so that the total number of cycles in a day gives an average frequency that is exactly the nominal value, so synchronous clocks do not accumulate error. For example, European utilities control the frequency of their grid once a day to make the total number of cycles in 24 hours
442:
A clock that employs electricity in some form to power a conventional clock mechanism is an electromechanical clock. Any spring or weight driven clock that uses electricity (either AC or DC) to rewind the spring or raise the weight of a mechanical clock then is an electromechanical clock. In
657:
clocks was that the motor could be started in either direction, so if the starter knob was spun the wrong way the clock would run backwards, the hands turning counterclockwise. Later manual-start clocks had ratchets or other linkages which prevented backwards starting. The invention of the
583:
at 60 Hz and 3000 RPM at 50 Hz. However most electric clocks have rotors with more magnetic poles (teeth), consequently rotating at a smaller submultiple of line frequency. This allows the gear train which turns the hands to be built with fewer gears, saving money.
261:. They essentially count cycles of the power supply. While the actual frequency may vary with loading on the grid, the total number of cycles per 24 hours is maintained rigorously constant, so that these clocks can keep time accurately for long periods, barring
600:
of their current to the nominal value of 50 or 60 hertz. Although utility load variations cause frequency fluctuations which may result in errors of a few seconds during the course of a day, utilities periodically adjust the frequency of their current using
506:, providing an energy pulse to the moving oscillator. This oscillator is responsible for the accuracy of the clock. The electronic part would not generate electrical pulses if the oscillator was absent or did not move. The
359:
but the disadvantage of its electrical properties varying with the weather. He trialled various means of regulating the electricity and these models proved to be reliable across a range of meteorological conditions.
898:
873:
425:
invented the first synchronous electric clock in
Ashland, MA, which kept time from the oscillations of the power grid. In 1931, the Synclock was the first commercial synchronous electric clock sold in the UK.
617:
The over 7-minute time error that would have developed in electric clocks over much of N. America had they not been reset after the March 2016 switch to
Daylight Saving Time, and had TEC's not been utilized
662:
allowed self-starting clocks to be made, but since the clock would then restart after a power outage, the clock would give incorrect time instead of being stopped at the time of power interruption.
1183:
645:
that, had TECs not been inserted in 2016, there would have been over seven minutes lost by electrically timed clocks over much of the United States and Canada, as shown in Figure 8 of their paper.
418:
The first electric clocks had prominent pendulums because this was a familiar shape and design. Smaller clocks and watches with a spiral-balance are made on the same principles as pendulum clocks.
460:. These self-winding clock systems were usually low voltage DC. They were installed through the 1950s and by then systems with synchronous motor clocks were becoming the clock system of choice.
634:
560:
One of the gears turning the clock's hands has a shaft with a sliding friction fitting, so the clock's hands can be turned manually by a knob on the back or on the bottom, to set the clock.
958:
240:). This was the mechanism used in the first electric clocks, and is found in antique electric pendulum clocks. It is also found in a few modern decorative mantel and desk clocks.
1116:
393:
Numerous people were intent on inventing the electric clock with electromechanical and electromagnetic designs around the year 1840, such as
Wheatstone, Steinheil, Hipp,
265:; over months they are more accurate than a typical quartz clock. This was the most common type of clock from the 1930s but has now been mostly replaced by quartz clocks.
882:
438:
Master clock from synchronized school clock system. c.1928 Electromechanical movement winds each minute and impulses slave clocks each minute. Operates on 24 Volts DC
653:
The earliest synchronous clocks from the 1930s were not self-starting, and had to be started by spinning a starter knob on the back. A flaw in the design of these
1002:
529:
A synchronous electric clock does not contain a timekeeping oscillator such as a pendulum or balance wheel, but instead counts the oscillations of the AC
149:
were introduced in the 1980s. The first experimental electric clocks were constructed around the 1840s, but they were not widely manufactured until mains
1190:
125:
Telechron synchronous electric clock manufactured around 1940. By 1940, the synchronous clock became the most common type of clock in the United States
622:
974:
is the number of poles on the rotor. Many designs have 30 poles, so that the motor runs at 240 RPM (at 60 Hz) or 200 RPM (at 50 Hz).
638:
728:
1123:
838:
1817:
1653:
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correct. U.S. utilities correct their frequency once the cumulative error has reached 3–10 sec. This correction is known as the
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Some electric clocks have a simple two-pole synchronous motor which runs at one revolution per cycle of power, i.e., 3600
1213:
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990:
768:
89:
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61:
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keep time with a pendulum or balance wheel, but the pulses to keep it going are not provided by a mechanical movement and
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Synchronous motor clocks are rugged because they do not have a delicate pendulum or balance wheel. However, a temporary
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701:
68:
108:
394:
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The configuration of this device is comparatively very simple and reliable. The electric current powers either a
407:, is credited with establishing the production series, mass marketable electric clock. Hipp opened a workshop in
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is employed to keep the clock going instead of springs or weights. Later patents expanded on his original ideas.
42:
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will stop the clock, which will show the wrong time when power is restored. Some synchronous clocks (e.g.
2020:
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35:
145:. The term is often applied to the electrically powered mechanical clocks that were used before
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8:
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1437:
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121:
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1905:
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468:
2008:
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Brimarc, typical quartz clock movement specified accurate to within ±30 seconds/month
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causes the current through the second inductor, and the second inductor works as an
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has a conventional self-winding clock mechanism that is rewound electrically. The
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Pulsynetic, C40A, Waiting Train, Turret Clock (1940s/50?). Photographed in the
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2015:
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542:
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209:
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141:, as opposed to a mechanical clock which is powered by a hanging weight or a
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280:
are electric clocks which keep time by counting oscillations of a vibrating
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142:
919:
in revolutions per minute (RPM) is related to the number of poles by:
218:
have gear trains turned by a small spring or weighted lever, called a
2151:
2068:
1704:
1616:
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1572:
1462:
825:, filed February 26, 1917, issued October 29, 1918, on Google Patents
568:
510:
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262:
177:
Electric clocks can operate by several different types of mechanism:
324:
One of
Alexander Bain's early electromagnetic clocks, from the 1840s
24:
1719:
1562:
1472:
1330:
1320:
1083:
845:. Antiquarian Horological Society, London, UK. 2011. Archived from
477:
383:
368:
367:
of Verona invented and showed another electrostatic clock run with
352:
237:
189:
498:. When the magnet passes the first inductor or sensor, the simple
157:
replaced mechanical clocks as the most widely used type of clock.
2058:
2048:
1970:
1961:
1946:
1833:
1678:
1601:
1310:
571:) have an indicator which shows if it has stopped and restarted.
513:
of the mechanical oscillator should be several times per second.
404:
351:
of London invented the first electric clock. It was powered with
1848:
625:(NERC), a consensus-based industry organization, petitioned the
2156:
1315:
491:
340:
328:
292:
are quartz clocks which are periodically synchronized with the
553:. The rotation rate of the motor shaft is synchronized to the
521:
2166:
1915:
1606:
1554:
320:
153:
became available in the 1890s. In the 1930s, the synchronous
134:
533:
from its wall plug to keep time. It consists of a small AC
1305:
1291:
881:. London: Heywood & Co. pp. 95–100. Archived from
490:
The electromechanical oscillator component has an attached
1098:
602:
1049:
592:
The accuracy of synchronous clocks depends on how close
372:
that it could operate on one battery for over 50 years.
1260:
204:, but use electricity to rewind the mainspring with an
456:, which is an example of an electromechanical gravity
257:
as a timing source, by driving the clock gears with a
927:
761:
Sir
Francis Ronalds: Father of the Electric Telegraph
537:, which turns the clock's hands through a reduction
1067:
http://www.gps.gov/cgsic/meetings/2011/matsakis.pdf
212:. This mechanism is found mostly in antique clocks.
169:Electromechanical self-winding clock movement from
49:. Unsourced material may be challenged and removed.
952:
525:Clock radio with synchronous clock, from the 1950s
1079:"Appliance disruptions feared in power grid test"
2234:
1117:"NAESB Wholesale Electric Quadrant (WEQ) Update"
744:Aked, C.K. (1973). "The First Electric Clock".
623:North American Electric Reliability Corporation
786:"Remembering the First Battery-Operated Clock"
639:National Institute of Standards and Technology
1276:
1198:
1184:
516:
1155:Perpetual Electromotive of Giuseppe Zamboni
1149:Viradez, Michel. History of Electric Clocks
986:
984:
982:
980:
812:
397:, and Garnier, both in Europe and America.
272:replaced by the lower cost quartz movement.
1283:
1269:
1191:
1177:
968:is the line frequency (50/60 Hz) and
429:
949:
307:around the world. They are distinct from
109:Learn how and when to remove this message
977:
612:
520:
467:
463:
433:
327:
319:
164:
120:
1152:Katz, Eugenii. Alexander Bain Biography
1099:"North American Energy Standards Board"
783:
758:
188:, which keeps time with an oscillating
2235:
1214:Synchronous Motor and the Master Clock
1158:Chirkin, K. Electromechanical clocks.
1050:"Federal Energy Regulatory Commission"
867:
865:
863:
1264:
1172:
953:{\displaystyle v={\frac {120f}{p}}\,}
839:"Famous Names in Electrical Horology"
833:
831:
2217:
1003:"Frequency response - National Grid"
871:
743:
693:
648:
635:North American Energy Standard Board
627:Federal Energy Regulatory Commission
47:adding citations to reliable sources
18:
860:
699:
13:
828:
763:. London: Imperial College Press.
574:
472:Early French electromagnetic clock
14:
2264:
913:The speed of a synchronous motor
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2207:
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23:
1109:
1091:
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1024:
995:
907:
892:
704:. Elliott Sound. Archived from
34:needs additional citations for
803:
777:
752:
737:
719:
355:, a high voltage battery with
184:have a traditional mechanical
1:
1143:
246:rely on the 50 or 60 Hz
16:Clock powered by electricity
7:
2021:Geological history of Earth
702:"Build a Synchronous Clock"
665:
587:
10:
2269:
1373:Orders of magnitude (time)
784:Ronalds, B.F. (Jun 2015).
517:Synchronous electric clock
315:
216:Electric remontoire clocks
2202:
2144:
2097:
2084:Time translation symmetry
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1969:
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1200:Electric clock technology
843:Electrical Horology Group
1290:
687:
677:Shortt-Synchronome clock
545:which create a rotating
454:Shortt-Synchronome clock
182:Electromechanical clocks
160:
2253:19th-century inventions
2039:Absolute space and time
1690:Astronomical chronology
875:Electric Clocks, 2nd Ed
809:Perpetual Electromotive
430:Electromechanical clock
289:Radio-controlled clocks
236:from an electromagnet (
2089:Time reversal symmetry
1393:Italian six-hour clock
1207:Powerline synchronized
954:
759:Ronalds, B.F. (2016).
643:U.S. Naval Observatory
618:
541:. The motor contains
526:
473:
439:
415:for time measurement.
344:
325:
226:Electromagnetic clocks
174:
126:
1854:Time and fate deities
1799:The Unreality of Time
1738:A series and B series
1007:www2.nationalgrid.com
955:
888:on February 23, 2014.
616:
608:Time Error Correction
524:
471:
464:Electromagnetic clock
437:
403:, clockmaker born in
331:
323:
168:
124:
2105:Chronological dating
2074:Theory of relativity
1418:Daylight saving time
925:
872:Wise, S. J. (1952).
819:U.S. patent #1283434
790:Antiquarian Horology
746:Antiquarian Horology
631:Daylight Saving Time
549:which turns an iron
43:improve this article
2248:Scottish inventions
1398:Thai six-hour clock
1165:(1968): p. 43.
357:extremely long life
349:Sir Francis Ronalds
339:(The Secretariat),
337:Ministers' Building
333:Gents' of Leicester
255:electric power grid
137:that is powered by
1928:Rosy retrospection
1906:Mental chronometry
1730:Philosophy of time
950:
731:2015-07-04 at the
619:
594:electric utilities
527:
474:
440:
423:Henry Ellis Warren
345:
326:
305:dedicated stations
301:radio time signals
269:Tuning Fork clocks
244:Synchronous clocks
196:powered through a
175:
127:
2230:
2229:
2140:
2139:
2115:Circadian rhythms
1933:Tense–aspect–mood
1788:Temporal finitism
1665:
1664:
1641:Grandfather clock
1258:
1257:
1224:Synchronous motor
1219:Utility frequency
947:
821:Warren, Henry E.
770:978-1-78326-917-4
660:shaded-pole motor
649:Spin-start clocks
555:utility frequency
535:synchronous motor
482:electromechanical
259:synchronous motor
248:utility frequency
119:
118:
111:
93:
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2127:Glottochronology
1967:
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1883:Human experience
1743:B-theory of time
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1009:. Archived from
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494:that passes two
388:electric current
365:Giuseppe Zamboni
232:linkage, but by
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100:
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92:
58:"Electric clock"
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2189:Time immemorial
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2054:Coordinate time
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1979:Geological time
1955:
1938:Time management
1901:Generation time
1885:
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1087:. 27 June 2011.
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901:Electric Clocks
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682:Automatic watch
668:
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575:Number of poles
531:utility current
519:
466:
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381:electromagnetic
318:
299:time scale via
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115:
104:
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95:
52:
50:
40:
28:
17:
12:
11:
5:
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2132:Time geography
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2122:Clock reaction
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1921:time signature
1918:
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1763:Eternal return
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1755:
1750:
1748:Chronocentrism
1745:
1740:
1734:
1732:
1726:
1725:
1723:
1722:
1717:
1712:
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1697:
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1614:
1604:
1599:
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1577:
1576:
1575:
1559:
1557:
1551:
1550:
1548:
1547:
1540:
1535:
1533:Hindu Panchang
1530:
1525:
1520:
1515:
1510:
1505:
1500:
1499:
1498:
1493:
1488:
1477:
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1327:
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1308:
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1234:
1230:
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1196:
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1188:
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1023:
994:
976:
961:
960:
946:
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939:
933:
930:
906:
891:
859:
827:
811:
802:
776:
769:
751:
736:
718:
700:Elliott, Rod.
691:
689:
686:
685:
684:
679:
674:
667:
664:
650:
647:
589:
586:
576:
573:
547:magnetic field
543:electromagnets
518:
515:
465:
462:
431:
428:
377:Alexander Bain
317:
314:
313:
312:
285:
282:quartz crystal
273:
266:
241:
234:magnetic force
223:
213:
206:electric motor
162:
159:
155:electric clock
151:electric power
131:electric clock
117:
116:
31:
29:
22:
15:
9:
6:
4:
3:
2:
2265:
2254:
2251:
2249:
2246:
2244:
2243:Clock designs
2241:
2240:
2238:
2223:
2215:
2213:
2205:
2204:
2201:
2195:
2192:
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2187:
2185:
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2173:
2170:
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2158:
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2149:
2147:
2143:
2133:
2130:
2128:
2125:
2123:
2120:
2116:
2113:
2112:
2111:
2110:Chronobiology
2108:
2106:
2103:
2102:
2100:
2096:
2090:
2087:
2085:
2082:
2080:
2077:
2075:
2072:
2070:
2067:
2065:
2062:
2060:
2057:
2055:
2052:
2050:
2047:
2045:
2044:Arrow of time
2042:
2040:
2037:
2036:
2034:
2032:
2028:
2022:
2019:
2017:
2016:Geochronology
2014:
2010:
2007:
2005:
2002:
2000:
1997:
1995:
1992:
1990:
1987:
1985:
1982:
1981:
1980:
1977:
1976:
1974:
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1968:
1965:
1963:
1958:
1952:
1948:
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1941:
1939:
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1934:
1931:
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1926:
1922:
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1907:
1904:
1902:
1899:
1897:
1894:
1893:
1891:
1889:
1884:
1880:
1872:
1869:
1868:
1867:
1866:Wheel of time
1864:
1860:
1857:
1856:
1855:
1852:
1850:
1847:
1845:
1842:
1840:
1837:
1835:
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1807:
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1739:
1736:
1735:
1733:
1731:
1727:
1721:
1718:
1716:
1713:
1711:
1710:Periodization
1708:
1706:
1703:
1701:
1698:
1696:
1693:
1691:
1688:
1687:
1685:
1680:
1677:
1675:
1672:
1671:
1668:
1656:
1655:
1651:
1650:
1649:
1648:
1644:
1642:
1639:
1637:
1636:Digital clock
1634:
1632:
1629:
1625:
1622:
1618:
1615:
1613:
1610:
1609:
1608:
1605:
1603:
1600:
1598:
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1593:
1590:
1586:
1583:
1582:
1581:
1578:
1574:
1571:
1570:
1569:
1566:
1565:
1564:
1561:
1560:
1558:
1556:
1552:
1546:
1545:
1541:
1539:
1536:
1534:
1531:
1529:
1526:
1524:
1521:
1519:
1516:
1514:
1511:
1509:
1506:
1504:
1501:
1497:
1494:
1492:
1489:
1487:
1484:
1483:
1482:
1479:
1478:
1476:
1474:
1470:
1464:
1461:
1459:
1456:
1454:
1451:
1449:
1446:
1444:
1441:
1439:
1436:
1434:
1431:
1429:
1426:
1424:
1421:
1419:
1416:
1414:
1413:Relative hour
1411:
1409:
1408:24-hour clock
1406:
1404:
1403:12-hour clock
1401:
1399:
1396:
1394:
1391:
1390:
1388:
1386:
1380:
1374:
1371:
1369:
1366:
1364:
1361:
1359:
1356:
1354:
1351:
1350:
1348:
1346:
1342:
1339:
1337:
1332:
1328:
1322:
1319:
1317:
1314:
1312:
1309:
1307:
1304:
1303:
1301:
1297:
1293:
1286:
1281:
1279:
1274:
1272:
1267:
1266:
1263:
1251:
1248:
1246:
1243:
1241:
1238:
1237:
1235:
1231:
1225:
1222:
1220:
1217:
1215:
1212:
1211:
1209:
1205:
1201:
1194:
1189:
1187:
1182:
1180:
1175:
1174:
1171:
1164:
1161:
1157:
1154:
1151:
1148:
1147:
1129:on 2022-12-06
1125:
1118:
1112:
1104:
1103:www.naesb.org
1100:
1094:
1086:
1085:
1080:
1074:
1068:
1063:
1055:
1051:
1045:
1037:
1033:
1027:
1013:on 2017-11-03
1012:
1008:
1004:
998:
992:
987:
985:
983:
981:
973:
972:
967:
966:
944:
940:
937:
931:
928:
921:
920:
918:
917:
910:
903:
902:
895:
884:
877:
876:
868:
866:
864:
849:on 2012-05-07
848:
844:
840:
834:
832:
824:
823:Timing device
820:
815:
806:
791:
787:
780:
772:
766:
762:
755:
747:
740:
734:
730:
727:
722:
708:on 2018-07-11
707:
703:
696:
692:
683:
680:
678:
675:
673:
670:
669:
663:
661:
656:
646:
644:
640:
636:
632:
628:
624:
621:In 2011, the
615:
611:
609:
604:
599:
595:
585:
582:
572:
570:
566:
561:
558:
556:
552:
548:
544:
540:
536:
532:
523:
514:
512:
509:
505:
504:electromagnet
501:
497:
493:
488:
486:
483:
479:
470:
461:
459:
455:
450:
446:
436:
427:
424:
419:
416:
414:
410:
406:
402:
401:Matthäus Hipp
398:
396:
391:
389:
385:
382:
378:
373:
370:
366:
361:
358:
354:
350:
342:
338:
334:
330:
322:
310:
306:
303:broadcast by
302:
298:
295:
291:
290:
286:
283:
279:
278:
277:Quartz clocks
274:
270:
267:
264:
260:
256:
253:
249:
245:
242:
239:
235:
231:
227:
224:
221:
217:
214:
211:
210:electromagnet
207:
203:
199:
195:
194:balance wheel
191:
187:
183:
180:
179:
178:
172:
167:
158:
156:
152:
148:
147:quartz clocks
144:
140:
136:
132:
123:
113:
110:
102:
91:
88:
84:
81:
77:
74:
70:
67:
63:
60: –
59:
55:
54:Find sources:
48:
44:
38:
37:
32:This article
30:
26:
21:
20:
2184:Time capsule
2178:Tempus fugit
2176:
2098:Other fields
1797:
1778:Perdurantism
1700:Calendar era
1652:
1645:
1631:Cuckoo clock
1568:astronomical
1542:
1368:Unit of time
1299:Key concepts
1245:Atomic clock
1240:Quartz clock
1199:
1162:
1159:
1131:. Retrieved
1124:the original
1111:
1102:
1093:
1082:
1073:
1062:
1054:www.ferc.gov
1053:
1044:
1036:www.nerc.com
1035:
1026:
1015:. Retrieved
1011:the original
1006:
997:
970:
969:
964:
963:
915:
914:
909:
900:
899:Wise (1952)
894:
883:the original
874:
851:. Retrieved
847:the original
842:
822:
814:
805:
793:. Retrieved
789:
779:
760:
754:
745:
739:
721:
710:. Retrieved
706:the original
695:
672:Master clock
654:
652:
620:
591:
578:
565:power outage
562:
559:
528:
489:
475:
445:master clock
441:
420:
417:
399:
392:
374:
362:
346:
309:clock radios
297:atomic clock
287:
275:
268:
243:
225:
215:
181:
176:
154:
130:
128:
105:
96:
86:
79:
72:
65:
53:
41:Please help
36:verification
33:
2194:Time travel
2172:System time
2079:Time domain
2064:Proper time
1888:use of time
1859:Father Time
1839:Immortality
1829:Ages of Man
1758:Endurantism
1715:Regnal year
1695:Big History
1624:water-based
1523:Solar Hijri
1433:Hexadecimal
1383:Measurement
1345:Chronometry
1331:Measurement
1250:Radio clock
904:, p.101–104
449:slave clock
413:chronograph
171:Switzerland
139:electricity
2237:Categories
1896:Chronemics
1871:Kalachakra
1783:Presentism
1768:Eternalism
1674:Chronology
1612:mechanical
1563:Main types
1481:Main types
1233:Electronic
1144:References
1133:2022-01-07
1017:2016-06-03
991:NIST Paper
853:2011-12-16
712:2016-12-13
655:spin-start
539:gear train
485:oscillator
458:remontoire
409:Reutlingen
263:power cuts
230:escapement
220:remontoire
202:mainspring
198:gear train
143:mainspring
99:March 2011
69:newspapers
2152:Leap year
2069:Spacetime
1943:Yesterday
1844:Dreamtime
1818:Mythology
1705:Deep time
1617:stopwatch
1592:hourglass
1573:astrarium
1503:Gregorian
1496:Lunisolar
1473:Calendars
1463:Time zone
1336:standards
598:frequency
596:keep the
569:Telechron
511:frequency
500:amplifier
496:inductors
421:In 1918,
375:In 1840,
363:In 1815,
353:dry piles
347:In 1814,
2212:Category
1960:Time in
1951:Tomorrow
1813:Religion
1753:Duration
1720:Timeline
1654:Timeline
1453:Sidereal
1321:Eternity
1084:CBS News
729:Archived
666:See also
641:and the
588:Accuracy
508:resonant
478:pendulum
384:pendulum
369:dry pile
238:solenoid
190:pendulum
186:movement
2222:Commons
2145:Related
2059:Instant
2049:Chronon
2031:Physics
1971:Geology
1962:science
1834:Destiny
1679:History
1647:History
1602:sundial
1585:quantum
1528:Chinese
1518:Islamic
1428:Decimal
1423:Chinese
1385:systems
1311:Present
610:(TEC).
405:Germany
395:Breguet
386:and an
316:History
250:of the
83:scholar
2162:Moment
2157:Memory
2009:period
1597:marine
1580:atomic
1555:Clocks
1513:Hebrew
1508:Julian
1443:Metric
1316:Future
1160:Radio,
1032:"NERC"
962:where
767:
492:magnet
480:or an
341:Yangon
85:
78:
71:
64:
56:
2167:Space
1999:epoch
1989:chron
1947:Today
1916:tempo
1911:Music
1773:Event
1607:watch
1491:Lunar
1486:Solar
1458:Solar
1448:Roman
1438:Hindu
1127:(PDF)
1120:(PDF)
886:(PDF)
879:(PDF)
795:8 Apr
688:Notes
551:rotor
200:by a
161:Types
135:clock
133:is a
90:JSTOR
76:books
1886:and
1849:Kāla
1544:List
1538:Maya
1334:and
1306:Past
1292:Time
797:2016
765:ISBN
62:news
2004:era
1994:eon
1984:age
1363:TAI
1353:UTC
938:120
603:UTC
581:RPM
294:UTC
208:or
192:or
129:An
45:by
2239::
1949:–
1945:–
1358:UT
1101:.
1081:.
1052:.
1034:.
1005:.
979:^
862:^
841:.
830:^
788:.
487:.
252:AC
1284:e
1277:t
1270:v
1192:e
1185:t
1178:v
1163:7
1136:.
1105:.
1056:.
1038:.
1020:.
971:p
965:f
945:p
941:f
932:=
929:v
916:v
856:.
799:.
773:.
748:.
715:.
343:.
311:.
173:.
112:)
106:(
101:)
97:(
87:·
80:·
73:·
66:·
39:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
