The tick duration must be positive. If it has a part smaller than a whole millisecond, then the whole duration must divide into one second without leaving a remainder. All normal tick durations will match these criteria, including any multiple of hours, minutes, seconds and milliseconds, and sensible nanosecond durations, such as 20ns, 250,000ns and 500,000ns.

There are cheaper alarm clocks on the market, but the aesthetically minded Kikkerland Retro is hard to top. The alarm clock may look like something you’d find at a thrift store, but nowadays, there’s a large market for all things vintage and nostalgic. This retro design incorporates an ivory face and glow-in-the-dark minute and hour hands to ensure clear readouts even in the middle of the night.

If you have a serious problem sleeping through your alarm, this retro little clock is for you. Because it doesn’t have a snooze button, you’ll be forced to either shut the alarm off completely and risk oversleeping, or you’ll learn to rise with the alarm. Also good: it’s doesn’t have an annoying ticking sound like other vintage clocks, so you won’t be kept awake at night.
Use of a Clock is optional. All key date-time classes also have a now() factory method that uses the system clock in the default time zone. The primary purpose of this abstraction is to allow alternate clocks to be plugged in as and when required. Applications use an object to obtain the current time rather than a static method. This can simplify testing.
Electric currents can be used to replace the weight or spring as a source of power and as a means of signaling time indications from a central master clock to a wide range of distant indicating dials. Invented in 1840, the first battery electric clock was driven by a spring and pendulum and employed an electrical impulse to operate a number of dials. Considerable experimental work followed, and it was not until 1906 that the first self-contained battery-driven clock was invented.
More than just a tool for keeping track of the time, this eye-catching wall clock helps turn any empty wall into an artful display. Crafted from injection plastic finished in a sleek metallic tone, it features a circular center with rods all around extending to stage the numbers of an analog dial. Measuring 16'' in diameter, it makes a statement on your kitchen or entryway wall without dominating the decor.
Don't settle for a simple wall clock to merely ensure you’re on time. Bring both function and French flair to your space with this oversized 29" oval wall clock. Made from manufactured wood, it showcases a typographic motif in the center that reads "Antiquite de Paris 1887" for a dash of antique inspiration. Classic Roman numerals and spade-style hands help you keep an eye on the hour, while a distressed finish completes the design with well-worn charm. Once you pop in a battery (not...

Though no longer our first pick of timepiece thanks to the smart phone, this old-fashioned clock still scores points for form. Measuring 6.25'' H x 2.5'' W x 5'' D, this compact clock’s face is encased in a metal case with a brushed nickel finish and convex glass lens, while its faded dial stays in step with vintage styling. This item is battery operated, but does not emit a loud ticking noise, so you can snooze to your heart's content.


In 1815, Francis Ronalds published the first electric clock powered by dry pile batteries.[48] Alexander Bain, Scottish clockmaker, patented the electric clock in 1840. The electric clock's mainspring is wound either with an electric motor or with an electromagnet and armature. In 1841, he first patented the electromagnetic pendulum. By the end of the nineteenth century, the advent of the dry cell battery made it feasible to use electric power in clocks. Spring or weight driven clocks that use electricity, either alternating current (AC) or direct current (DC), to rewind the spring or raise the weight of a mechanical clock would be classified as an electromechanical clock. This classification would also apply to clocks that employ an electrical impulse to propel the pendulum. In electromechanical clocks the electricity serves no time keeping function. These types of clocks were made as individual timepieces but more commonly used in synchronized time installations in schools, businesses, factories, railroads and government facilities as a master clock and slave clocks.
The timekeeping element of a quartz clock consists of a ring of quartz about 2.5 inches (63.5 mm) in diameter, suspended by threads and enclosed in a heat-insulated chamber. Electrodes are attached to the surfaces of the ring and connected to an electrical circuit in such a manner as to sustain oscillations. Since the frequency of vibration, 100,000-hertz, is too high for convenient time measurement, it is reduced by a process known as frequency division or demultiplication and applied to a synchronous motor connected to a clock dial through mechanical gearing. If a 100,000 hertz frequency, for example, is subjected to a combined electrical and mechanical gearing reduction of 6,000,000 to 1, then the second hand of the synchronous clock will make exactly one rotation in 60 seconds. The vibrations are so regular that the maximum error of an observatory quartz-crystal clock is only a few ten-thousandths of a second per day, equivalent to an error of one second every 10 years.
Small in size but striking in style, this eye-catching wall clock brings a dash of contemporary flair to any arrangement in your home. Showcasing a sunburst silhouette measuring 20" in diameter, this round silver-finished design is crafted with an iron and mirrored frame comprised of black spokes with orb-like accents. A petite glass clock face with sword-style hands sits in the center, allowing you to keep an eye on the hour in any room.

Mixing modern minimalism with industrial influence, this round 28" wall clock is as much a decorative accent as it is a practical timepiece. Crafted from metal, it showcases sizable Roman numerals and small spade-style hands to help you keep an eye on the hour. Its black and gold finish gives it an antiqued appearance, while its open design ensures it won’t overwhelm your arrangement. This piece requires two AA batteries (not included) to operate.
Minimalist design and modern style combine in this 11" wall clock. Set under a clear glass lens on chrome posts, the streamlined dial showcases chrome military indicators on the 12, 3, 6, and 9 over a warm brown woodgrain background, while the unadorned face of the clock takes the form of a brushed metal disk. Operated by a AA battery (not included), a quartz crystal movement keeps the simple baton hour, minute, and second hands ticking away in time.
In addition to radio, recent clock radios have other music sources such as iPod, iPhone, and/or audio CD. When the alarm is triggered, it can play a set radio station or the music from a selected music source to awaken the sleeper. These models usually come with a dock for iPod/iPhone that also charges the device while it is docked. They can play FM/AM radio, iPod/iPhone or CD like a typical music player as well (without being triggered by the alarm function). A few popular models offer "nature sounds" like rain, forest, fire, sea, waterfall etc., in place of the buzzer.
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The oldest surviving clock in England is that at Salisbury Cathedral, which dates from 1386. A clock erected at Rouen, France, in 1389 is still extant, and one built for Wells Cathedral in England is preserved in the Science Museum in London. The Salisbury clock strikes the hours, and those of Rouen and Wells also have mechanisms for chiming at the quarter hour. These clocks are large, iron-framed structures driven by falling weights attached to a cord wrapped around a drum and regulated by a mechanism known as a verge (or crown wheel) escapement. Their errors probably were as large as a half hour per day. The first domestic clocks were smaller wall-mounted versions of these large public clocks. They appeared late in the 14th century, and few examples have survived; most of them, extremely austere in design, had no cases or means of protection from dust.
In a pendulum clock an escape wheel is allowed to rotate through the pitch of one tooth for each double swing of the pendulum and to transmit an impulse to the pendulum to keep it swinging. An ideal escapement would transmit the impulse without interfering with the free swing, and the impulse should be as uniform as possible. The double three-legged gravity escapement, which achieves the second of these but not the first, was invented by Edmund Beckett, afterward Lord Grimthorpe, and used by him for the great clock at Westminster, now generally known as Big Ben, which was installed in 1859. It became the standard for all really accurate tower clocks.
Howard Miller 625-613 Company Time II Large Wall Clock is a 34" wall clock with an antique nickel frame. The center dial is a bubbled panel that is heavily distressed and deeply dented for an aged appearance. The individual off-white number panels are curved and dented with Black Roman numerals centered on each panel. The accurate quartz movement requires one "AA" battery. Always measure your area to make sure the wall you have will accommodate this large of clock. One Year Warranty and Free Shipping.
The timekeeping element of a quartz clock consists of a ring of quartz about 2.5 inches (63.5 mm) in diameter, suspended by threads and enclosed in a heat-insulated chamber. Electrodes are attached to the surfaces of the ring and connected to an electrical circuit in such a manner as to sustain oscillations. Since the frequency of vibration, 100,000-hertz, is too high for convenient time measurement, it is reduced by a process known as frequency division or demultiplication and applied to a synchronous motor connected to a clock dial through mechanical gearing. If a 100,000 hertz frequency, for example, is subjected to a combined electrical and mechanical gearing reduction of 6,000,000 to 1, then the second hand of the synchronous clock will make exactly one rotation in 60 seconds. The vibrations are so regular that the maximum error of an observatory quartz-crystal clock is only a few ten-thousandths of a second per day, equivalent to an error of one second every 10 years.
"Very easy to use...Excellent Product...I cannot say enough about this clock -I love the fact mum is hearing my voice on a daily basis even though I live in another country....it's truly a great concept - great design and well worth it for elderly - for dementia patients or even for individuals who need a talking reminder about daily tasks or appts."
The Philips Wake-Up Light offers a choice of five pleasant nature sounds — or for the more traditionally minded, FM radio — for your morning wake-up call, but the real star of the show is the sunlight simulation. Twenty to forty minutes before your programmed wake-up time (you set both times), the clock will slowly begin to simulate the sunrise, complete with the softest dawn reds and oranges gently brightening into sunny, yellow light.

For convenience, distance, telephony or blindness, auditory clocks present the time as sounds. The sound is either spoken natural language, (e.g. "The time is twelve thirty-five"), or as auditory codes (e.g. number of sequential bell rings on the hour represents the number of the hour like the bell, Big Ben). Most telecommunication companies also provide a speaking clock service as well.

Acadia finish on select hardwoods and veneers is heavily distressed by scribes, and worm holes for a natural, rustic appearance — inspired by the natural yet rustic nature of reclaimed woods in beautiful patinas and burnished details. Features a multi-tiered flat top, distinctive columns with corbels frame the door. Circular spun antique nickel-finished dial with black Roman numerals, hour markers, and hands. Antique nickel-finished lyre pendulum. Quartz, battery-operated, triple-chime Harmonic movement plays choice of full Westminster or Ave Maria chimes with strike on the hour with 1/4, 1/2, and 3/4 chimes accordingly; Westminster chime and strike on the hour only; or Bim Bam chime on the hour only. Volume control and automatic nighttime chime shut-off option. Powered by two C sized batteries. One year warranty and Free Shipping
Molded by mid-century modern style, this 38" wall clock brings a bit of bold flair to any space in your home. Its generous size helps it grab glances (and compliments!) from guests, while its open and numberless design gives it a minimalist feel. Crafted from metal, this round silhouette sports a gold finish with silver-finished hands in the center for subtle contrast. Two AA batteries (not included) are required to operate.
Fortunately, Ruggie takes the ease and convenience out of simply rolling over and slapping “snooze.” With Ruggie, you must apply pressure to a plush mat for three seconds to stop the alarm. The alarm can be set to 120 decibels, too, to further annoy you out of bed. For sake of perspective, 120 decibels is on par with the noise level of a chainsaw. Pleasant.
Clock radios are powered by AC power from the wall socket. In the event of a power interruption, older electronic digital models used to reset the time to midnight (00:00) and lose alarm settings. This would cause failure to trigger the alarm even if the power is restored. To solve this issue, they trigger the alarm at 00:01 after a reset, so that at least the user is able to correct the clock and alarm settings. Most of the recent clock radios use a battery backup to maintain the time and alarm settings. Some advanced radio clocks (not to be confused with clocks with AM/FM radios) have a feature which sets the time automatically using signals from atomic clock-synced time signal radio stations such as WWV, making the clock accurate and immune to time reset due to power interruptions.

If you're outfitting your new home or apartment, check out more of our great buying guides like the best bar stools, the best light bulbs, the best coffee tables, the best area rugs, the best mattress toppers, the best sheets, the best mattresses, the best pillows, the best clothes hangers, the best cordless vacuum cleaners, the best laundry baskets and hampers, and the best home security cameras you can buy.
Clockmakers developed their art in various ways. Building smaller clocks was a technical challenge, as was improving accuracy and reliability. Clocks could be impressive showpieces to demonstrate skilled craftsmanship, or less expensive, mass-produced items for domestic use. The escapement in particular was an important factor affecting the clock's accuracy, so many different mechanisms were tried.

Certainly not just for telling time, this oversized wall clock makes a statement whether set in the entryway or above your living room mantel. Its frame is crafted from metal with an antiqued silver leaf design for metallic allure. The openwork design allows it to seamlessly blend with your ensemble, while a fun analog dial lends a pop of playful appeal. Requires one AA battery to operate.


Whether you’re styling an accent wall or rounding out your decor, a retro-inspired wall clock like this one draws the eye while adding some utility to your ensemble. The large numbers make this clock easy to read, and with quartz movement, it features a more accurate reading. The minimalist black and white face and the sleek silver frame imbue it with contemporary appeal, making this piece easy to hang in a variety of design styles. Measures 15'' in diameter.

An alarm clock (alarm for short) is a clock that is designed to alert an individual or group of individuals at specified time. The primary function of these clocks is to awaken people from their night's sleep or short naps; they are sometimes used for other reminders as well. Most use sound; some use light or vibration. Some have sensors to identify when a person is in a light stage of sleep, in order to avoid waking someone who is deeply asleep, which causes tiredness, even if the person has had adequate sleep. To stop the sound or light, a button or handle on the clock is pressed; most clocks automatically stop the alarm if left unattended long enough. A classic analog alarm clock has an extra hand or inset dial that is used to specify the time at which to activate the alarm. Alarm clocks are also found on mobile phones, watches, and computers.
late 14c., clokke, originally "clock with bells," probably from Middle Dutch clocke (Dutch klok) "a clock," from Old North French cloque (Old French cloke, Modern French cloche), from Medieval Latin (7c.) clocca "bell," probably from Celtic (cf. Old Irish clocc, Welsh cloch, Manx clagg "a bell") and spread by Irish missionaries (unless the Celtic words are from Latin); ultimately of imitative origin.

c. 1350–1400, Middle English clokke, clok, cloke, from Middle Dutch clocke (“bell, clock”), from Old Northern French cloque (“bell”), from Medieval Latin clocca, probably of Celtic origin, from Proto-Celtic *klokkos (“bell”) (compare Welsh cloch, Irish clog), from Proto-Indo-European *klēg-, *klōg-. Related to Old English clucge, Saterland Frisian Klokke (“bell; clock”), Low German Klock (“bell, clock”), German Glocke, Swedish klocka. Related to laugh.
Transform an open and plain wall into a timeless focal point with this oversized clock, a versatile addition that lends any room in your home a touch of charm. Crafted of metal, this gray-finished piece features inner and outer rings connected by large Roman numerals that bring classic appeal to your space. This open-faced design is perfect for making a statement without overwhelming your arrangement. Mount this analog over a well-worn leather sofa so you don't lose track of the time as you...
Here is a clock that will look great in any room in the house and it never needs a plug! This Water Clock is powered by ordinary tap water. Never needs batteries or electricity. Just fill this Water clock with water and you are on your way to more eco-friendly home. After about 6 months to a year you may need to dump the water out (your can pour it into a plant) and refill. The clock will remember the time as you do so. It even has an alarm. Great for traveling as well. Why would you ever use...
The primary purpose of a clock is to display the time. Clocks may also have the facility to make a loud alert signal at a specified time, typically to waken a sleeper at a preset time; they are referred to as alarm clocks. The alarm may start at a low volume and become louder, or have the facility to be switched off for a few minutes then resume. Alarm clocks with visible indicators are sometimes used to indicate to children too young to read the time that the time for sleep has finished; they are sometimes called training clocks.

There’s nothing like seeing the time blasted on the wall in sharp red LED display. It gives you the perfect sense of, “Oh crap, I’m going to be late.” Projection alarm clocks are just plain awesome, and it’s especially true in this model. This isn’t just another electric alarm clock—you get advanced SelfSet technology thrown into this bad boy that’s going to correct the time and date for you, so the Daylight Savings Time ghost of Benjamin Franklin doesn’t haunt you.

In a typical verge-and-foliot escapement, the weighted rope unwinds from the barrel, turning the toothed escape wheel. Controlling the movement of the wheel is the verge, a vertical rod with pallets at each end. When the wheel turns, the top pallet stops it and causes the foliot, with its regulating weights, to oscillate. This oscillation turns the verge and releases the top pallet. The wheel advances until it is caught again by the bottom pallet, and the process repeats itself. The actions of the escapement stabilize the power of the gravitational force and are what produce the ticktock of weight-driven clocks.
The word horologia (from the Greek ὥρα, hour, and λέγειν, to tell) was used to describe early mechanical clocks,[15] but the use of this word (still used in several Romance languages) [16] for all timekeepers conceals the true nature of the mechanisms. For example, there is a record that in 1176 Sens Cathedral installed a ‘horologe’[17] but the mechanism used is unknown. According to Jocelin of Brakelond, in 1198 during a fire at the abbey of St Edmundsbury (now Bury St Edmunds), the monks 'ran to the clock' to fetch water, indicating that their water clock had a reservoir large enough to help extinguish the occasional fire.[18] The word clock (from the Celtic words clocca and clogan, both meaning "bell"), which gradually supersedes "horologe", suggests that it was the sound of bells which also characterized the prototype mechanical clocks that appeared during the 13th century in Europe.

If you’ve never seen an alarm clock that can project the time onto the wall, you may be surprised at how handy this function can be. This Mesqool clock can project the time onto the ceiling, the curtains, or just about any other surface, thanks to the 180-degree swivel. So instead of squinting at the clock through sleepy eyes in the morning, you can just look up at the ceiling. The clock also includes AM/FM Radio, so you can listen to your favorite morning talk shows or follow along with your sports team while you get ready in the morning.


Remember a time before everything was digital? Yeah… we don’t either. But a few excellent time-tested products pop up out of the woodwork from time to time, and a traditional dual bell alarm clock does the trick. The hands move silently while you sleep, and buzz like a mother when it’s time to rise and shine. If you’re like us, you’re sometimes bothered by LED flashing you in the face all night. With Peakeep Twin Bell Stereoscopic Clock, you simply touch the button to activate the stereoscopic dial backlight, check the time, and they cop-out for another fifteen minutes. Don’t worry – Peakeep will wake you up.
In a master clock system, electricity is used to give direct impulses to the pendulum, which in turn causes the clock’s gear train to move, or to lift a lever after it has imparted an impulse to the pendulum. In various modern master clocks the pendulum operates a light count wheel that turns through the pitch of one tooth every double swing and is arranged to release a lever every half minute. This lever gives an impulse to the pendulum and is then restored to its original position by an electromagnet. The pulse of current that operates the electromagnet can also be transmitted to a series of distant dials, or slave clocks, advancing the hands of each through the space of a half minute. Thus, a master clock can control scores of dials in a large group of buildings, as well as such other apparatus as time recorders and sirens.
Scientific studies on sleep having shown that sleep stage at awakening is an important factor in amplifying sleep inertia. Alarm clocks involving sleep stage monitoring appeared on the market in 2005.[22] The alarm clocks use sensing technologies such as EEG electrodes and accelerometers to wake people from sleep.[23][24]Dawn simulators are another technology meant to mediate these effects.[25]

The OK to Wake! alarm clock and nap timer is a useful tool for parents with young kids learning the importance of sleep schedules. When it's OK for a child to get out of bed (aka when the alarm or nap timer goes off) the clock will light up green, providing an easy-to-understand visual cue for little ones to start their day. It even has interchangeable face plates to suit aesthetic preferences.
In 1735, Harrison built his first chronometer, which he steadily improved on over the next thirty years before submitting it for examination. The clock had many innovations, including the use of bearings to reduce friction, weighted balances to compensate for the ship's pitch and roll in the sea and the use of two different metals to reduce the problem of expansion from heat. The chronometer was tested in 1761 by Harrison's son and by the end of 10 weeks the clock was in error by less than 5 seconds.[43]

Brimming with an antiqued appeal, this clean-lined wood and glass wall clock brings function and flair to your home. Its distressed details pair perfectly with reclaimed teak wood accents while its neutral color palettes blend effortlessly into any monochromatic look. Add this piece to the den to bring the traditional flair to a cozy coastal arrangement, then pair it with woven rattan furniture and driftwood decor for a complementing look. Round out the room with a hand-woven jute rug to define...


In mechanical clocks, the low Q of the balance wheel or pendulum oscillator made them very sensitive to the disturbing effect of the impulses of the escapement, so the escapement had a great effect on the accuracy of the clock, and many escapement designs were tried. The higher Q of resonators in electronic clocks makes them relatively insensitive to the disturbing effects of the drive power, so the driving oscillator circuit is a much less critical component.[2]

An alarm clock (alarm for short) is a clock that is designed to alert an individual or group of individuals at specified time. The primary function of these clocks is to awaken people from their night's sleep or short naps; they are sometimes used for other reminders as well. Most use sound; some use light or vibration. Some have sensors to identify when a person is in a light stage of sleep, in order to avoid waking someone who is deeply asleep, which causes tiredness, even if the person has had adequate sleep. To stop the sound or light, a button or handle on the clock is pressed; most clocks automatically stop the alarm if left unattended long enough. A classic analog alarm clock has an extra hand or inset dial that is used to specify the time at which to activate the alarm. Alarm clocks are also found on mobile phones, watches, and computers.

"Love it...Love it....Just a basic alarm clock needed one to check that my FM transmitter is on the correct frequency one that had a digital tuner fits the bill just fine and a battery back up clock for time announcements ....What can I say, it's a quality alarm, that never fails, and is not expensive Not once has this alarm failed to wake me up, Digits are bright and easy to see If I were to say something negative, The time is a little too fast (in a month you'll notice your like a minute or two ahead of the actual time, easy fix though) And the radio connection needs to better"
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