In atomic clocks the controller is an evacuated microwave cavity attached to a microwave oscillator controlled by a microprocessor. A thin gas of caesium atoms is released into the cavity where they are exposed to microwaves. A laser measures how many atoms have absorbed the microwaves, and an electronic feedback control system called a phase-locked loop tunes the microwave oscillator until it is at the frequency that causes the atoms to vibrate and absorb the microwaves. Then the microwave signal is divided by digital counters to become the clock signal.[72]
“I bought this light because my partner and I need to be up early for work, but our bedroom has very poor natural light. Within a week, I’ve already noticed a difference in my energy levels and mood. The sunrise simulation works perfectly; by the time the ‘alarm’ (peaceful bird noises) goes off, I’m already feeling naturally awake — not groggy or jolted out of my sleep. I feel much more rested, and my average resting heart rate reflects that. I also really love the sunset feature. I wasn’t expecting to get much use out of it, but I feel like it does a great job of helping me settle into bed at the end of the day.”
If you’re looking for a calmer start to your day, you might want to try the Wake-Up Light. It gradually gets you up and out of bed with a colored sunrise simulation and a selection of nature-inspired sounds, so that you can start the day feeling refreshed and energized—as if you had woken up naturally. For anyone who finds it particularly hard to get out of bed when it’s cold and dark out, this alarm clock makes those winter mornings that little bit easier. It also comes with a nighttime dimming feature so that you can make sure you’re getting your best night’s rest.
A major stimulus to improving the accuracy and reliability of clocks was the importance of precise time-keeping for navigation. The position of a ship at sea could be determined with reasonable accuracy if a navigator could refer to a clock that lost or gained less than about 10 seconds per day. This clock could not contain a pendulum, which would be virtually useless on a rocking ship. In 1714, the British government offered large financial rewards to the value of 20,000 pounds,[42] for anyone who could determine longitude accurately. John Harrison, who dedicated his life to improving the accuracy of his clocks, later received considerable sums under the Longitude Act.

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.
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.
Keep track of time and exude antiqued style with this bold 24-inch oversized wall clock. Crafted from metal and wood, this round analog clock operates on quartz crystal movement and is embellished with a white background and black needles. Roman numerals lend a traditional touch, and small geometric details add extra dimension to the piece. Use this piece to help create a chic French countryside aesthetic in your kitchen. Start by painting the walls a light gray or beige tone with white trim....
Bolter, David J. Turing's Man: Western Culture in the Computer Age. The University of North Carolina Press, Chapel Hill, N.C. (1984). ISBN 0-8078-4108-0 pbk. Very good, readable summary of the role of "the clock" in its setting the direction of philosophic movement for the "Western World". Cf. picture on p. 25 showing the verge and foliot. Bolton derived the picture from Macey, p. 20.
With the application of the synchronous electric motor to clocks in 1918, domestic electric clocks became popular. A synchronous electric motor runs in step with the frequency of the electric power source, which in most countries alternates at 60 hertz (cycles per second). The electric motor is coupled to a reduction gearing that drives the clock hands at the correct rate.

With it's quality construction and stylish mid-century modern design, the 31.5" Rumi Mid Century Wall Clock is an attractive accent for the home. Crafted entirely of iron, this large wall clock features a dark brown distressed finish and large distressed gold hands. Minimalism is reflected in the clock's open pass-through design. This clock is a must-have for anyone in search of mid-century modern inspired decor.

If it has the iHome name attached to it, you know it’s going to be flashy. Their Bluetooth color changing clock hits home on all the necessary marks, allowing you to talk and end phone conversations with the touch of a button, as well as the five multiple LED color settings. It isn’t all about waking up in the morning; this alarm clock has you ready to go with a fully charged iPhone, fed sweet, sweet energy while you sleep. The last alarm clock you’ll ever need is staring you right in the face – it’s time to complete your iHome collection in style.
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...
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.
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.
Bring elegant, antique style to your walls with this 23.25" wall clock. Crafted of manufactured wood and plastic, this clock’s dial showcases large Arabic numerals printed in weathered beige over the hand-painted royal red face. A battery-operated movement keeps spade hour and minute hands ticking away in time over the words “Hotel Westminster” and “Pairs Rue de la Paix” written in swirling cursive script. Distressed details and fleur-de-lis accents round out the design, imbuing a...
Besides the Chinese astronomical clock of Su Song in 1088 mentioned above, 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. They no longer exist, but detailed descriptions of their design and construction survive,[22][23] and modern reproductions have been made.[23] They illustrate how quickly the theory of the mechanical clock had been translated into practical constructions, and also that one of the many impulses to their development had been the desire of astronomers to investigate celestial phenomena.
This large farmhouse wall clock measures 36 inches This large farmhouse wall clock measures 36 inches across the face and features horizontal cedar wood slats a white distressed finish and hand painted black Roman numerals. Finish will vary slightly depending on each unique wood tone and grain pattern. The clock includes a high torque quartz movement antique-style spade ...  More + Product Details Close
This farmhouse wall clock measures 30 in. across This farmhouse wall clock measures 30 in. across the face and features horizontal cedar wood slats a white distressed finish hand painted black Roman numerals in a Poster Condensed font and an inner accent ring with individual hour marks. It includes a high torque quartz movement antique-style spade hands and ...  More + Product Details Close

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.
It is undesirable to give someone a clock or (depending on the region) other timepiece as a gift. Traditional superstitions regard this as counting the seconds to the recipient's death. Another common interpretation of this is that the phrase "to give a clock" (simplified Chinese: 送钟; traditional Chinese: 送鐘) in Chinese is pronounced "sòng zhōng" in Mandarin, which is a homophone of a phrase for "terminating" or "attending a funeral" (both can be written as 送終 (traditional) or 送终 (simplified)). Cantonese people consider such a gift as a curse.[79]
In mechanical clocks this is done mechanically by a gear train, known as the wheel train. The gear train also has a second function; to transmit mechanical power from the power source to run the oscillator. There is a friction coupling called the 'cannon pinion' between the gears driving the hands and the rest of the clock, allowing the hands to be turned to set the time.[73]

If it has the iHome name attached to it, you know it’s going to be flashy. Their Bluetooth color changing clock hits home on all the necessary marks, allowing you to talk and end phone conversations with the touch of a button, as well as the five multiple LED color settings. It isn’t all about waking up in the morning; this alarm clock has you ready to go with a fully charged iPhone, fed sweet, sweet energy while you sleep. The last alarm clock you’ll ever need is staring you right in the face – it’s time to complete your iHome collection in style.
A minimalist twist on the traditional wall clock. Resolve to find contentment with the time you are given, without obsessing over the numbers. Feel things you have never felt before. Experience different points of view. Make the best of it. Live a life you are proud of. Discover the value of time with The Adam Schwoeppe Minimalist Circle Clock, an elegant eclectic timepiece. Revitalize your home decor as time passes silently with this modern black circle clock.
In order to shut off this loud alarm, you have to actually get out of bed and stand on the rug for three seconds. But if you find yourself cheating your alarm by crawling back into bed after those few seconds, you can extend the alarm for up to 30 seconds, ensuring you’ll be much more awake once the blood starts flowing to the other parts of your body.

Defined by its vintage silhouette, this round tabletop clock features two bells up above connected by a slender bridge. Its bold black numbers and classic pierced hands help you keep track of your day, while its alarm ensures you'll wake up on time to start your morning right. This metal design is offered in several bright shades with chipped accents that enhance its antique look. It requires one AA battery (not included).


This farmhouse wall clock measures 24 in. across This farmhouse wall clock measures 24 in. across the face and features horizontal cedar wood slats a white distressed finish hand painted black Roman numerals in a Poster Condensed font and an inner accent ring with individual hour marks. It includes a high torque quartz movement antique-style spade hands and ...  More + Product Details Close
Most digital computers depend on an internal signal at constant frequency to synchronize processing; this is referred to as a clock signal. (A few research projects are developing CPUs based on asynchronous circuits.) Some equipment, including computers, also maintains time and date for use as required; this is referred to as time-of-day clock, and is distinct from the system clock signal, although possibly based on counting its cycles.
This Digital Bluetooth AM/FM Dual Alarm Radio Tabletop Clock from Jensen makes getting up in the morning a more appealing proposition. With the option to wake to radio or alarm, you can start your day off right. It even has an aux input so you can connect a smartphone or music player, letting you play whatever tunes you like right from your nightstand.
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