The piezoelectric properties of crystalline quartz were discovered by Jacques and Pierre Curie in 1880.[49][50] The first crystal oscillator was invented in 1917 by Alexander M. Nicholson after which, the first quartz crystal oscillator was built by Walter G. Cady in 1921.[2] In 1927 the first quartz clock was built by Warren Marrison and J. W. Horton at Bell Telephone Laboratories in Canada.[51][2] The following decades saw the development of quartz clocks as precision time measurement devices in laboratory settings—the bulky and delicate counting electronics, built with vacuum tubes, limited their practical use elsewhere. The National Bureau of Standards (now NIST) based the time standard of the United States on quartz clocks from late 1929 until the 1960s, when it changed to atomic clocks.[52] In 1969, Seiko produced the world's first quartz wristwatch, the Astron.[53] Their inherent accuracy and low cost of production resulted in the subsequent proliferation of quartz clocks and watches.[49]
Keep time in style with this traditional tabletop clock, a great way to round out a decorative vignette while adding essential function. Crafted from wood and metal, this circular design sits atop a curved base and pairs an antique dial with a deep red finish. The glass-inlaid clock face sports glow-in-the-dark hands, so you can check the time in the wee hours and early evening, while a quartz movement keeps this design tickin’ and tockin’. Requires a battery.
You don't have to use all of those features, however. You can set them in a variety of combinations, or even turn all of them off except for the flashing red lights. You can also set the length of the alarm's ring from one to 60 minutes, and choose a snooze option from one to 30 minutes. Plus, the clock has dual alarms, so both you and your partner can have different wake-up times.
If you’re looking for a way to add some pizazz to your walls as well as some function, wall clocks are a great design choice. You can find a wall clock in almost every shape, style and color. From modern wall clocks like the sunburst clock to antique wall clocks such as the pendulum clock, there’s a style for every room and every home. Some are even designed to fit into specific rooms: there are dozens of kitchen clocks featuring faces shaped like teapots, cows, bottles of milk and more. There’s even incentive to go big, as large wall clocks can become a statement piece in the same way a large mirror or work of art can.
Now you can wake up to the sun without even opening your curtains. This alarm clock uses a gentle glow that simulates a sunrise, waking you gently and naturally, so you definitely won't want to murder it when it starts going off. Choose from five different calming sounds to pair with the gradual light for an all-around sensory experience, or just select the FM radio option (that you'll inevitably snooze once or twice).
Time can be smart, clever, ultra-stylish, functional and simple with this Cube Click Desktop Clock. This Cube Click Desktop Clock can tell you the time, date and temperature alternately in blue LED color on a black wood-effect block at the click of your fingers and automatically switches off when the room is quiet, lighting up again when the alarm goes off or as a response to clicked fingers or clapped hands. The numbers seem to float on the lovely wooden block, but that's just half the magic...
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
This metal wire case wall clock is finished in antique black with antique gold highlights. The pendulum bob, with matching finish, is an open circle, suspended on a metal pendulum. A black bezel surrounds the convex acrylic crystal. The dial features an antique Antique Red background with gold Arabic numerals and Antique gold spade hands. Quartz, non-chiming battery operated movement. One Year Warranty.
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.
Most digital clocks use electronic mechanisms and LCD, LED, or VFD displays; many other display technologies are used as well (cathode ray tubes, nixie tubes, etc.). After a reset, battery change or power failure, these clocks without a backup battery or capacitor either start counting from 12:00, or stay at 12:00, often with blinking digits indicating that the time needs to be set. Some newer clocks will reset themselves based on radio or Internet time servers that are tuned to national atomic clocks. Since the advent of digital clocks in the 1960s, the use of analog clocks has declined significantly.
Synchronous electric clocks do not have an internal oscillator, but count cycles of the 50 or 60 Hz oscillation of the AC power line, which is synchronized by the utility to a precision oscillator. The counting may be done electronically, usually in clocks with digital displays, or, in analog clocks, the AC may drive a synchronous motor which rotates an exact fraction of a revolution for every cycle of the line voltage, and drives the gear train. Although changes in the grid line frequency due to load variations may cause the clock to temporarily gain or lose several seconds during the course of a day, the total number of cycles per 24 hours is maintained extremely accurately by the utility company, so that the clock keeps time accurately over long periods.
Clocks have different ways of displaying time, connected to their internal clockwork type. Analog clocks usually indicate time using angles. Digital clocks display a numeric representation of time. Two numeric display formats are commonly used on digital clocks: 24-hour notation and 12-hour notation. Most digital clocks use electronic mechanisms and LCD, LED, or VFD displays. For convenience, distance, telephony or blindness, auditory clocks present the time as sounds. There are also clocks for the blind that have displays that can be read by using the sense of touch. Some of these are similar to normal analog displays, but are constructed so the hands can be felt without damaging them. The evolution of the technology of clocks continues today. The study of timekeeping is known as horology.
The ancient Greek philosopher Plato (428–348 BC) was said to possess a large water clock with an unspecified alarm signal similar to the sound of a water organ; he used it at night, possibly for signaling the beginning of his lectures at dawn (Athenaeus 4.174c).[2] The Hellenistic engineer and inventor Ctesibius (fl. 285–222 BC) fitted his clepsydras with dial and pointer for indicating the time, and added elaborate "alarm systems, which could be made to drop pebbles on a gong, or blow trumpets (by forcing bell-jars down into water and taking the compressed air through a beating reed) at pre-set times" (Vitruv 11.11).[3]

The Howard Miller Spokane 15.75" Wall Clock is a piece of classic design and features. This simple yet functional timepiece has a brushed aluminum finish. This round shape clock is very convenient and can be mounted on any wall of your home. This wall clock can be used for residential as well as commercial use as it has simple and subtle. This round wall clock from Spokane has a silver finished case with white background for ease at readability. This wall clock is numbered and features Arabic...
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.
Remember when the idea of chasing your alarm clock around the house was absolutely mad? Well, Clocky made it a reality, and they haven’t gone out of style yet. Bed shakers may work for some, but if you can ignore it and snooze on through, chasing your alarm clock around the room may be the next best thing. This mad machine can leap from three feet high, and if you’re trying to get some shut-eye on a Saturday, you can disable the wheels and make it stationary for the time being. Just don’t let that ruin your important meeting come 9:00 AM Monday morning. This little buzzer droid is going to make R2-D2 sounds while it zips around the room, egging you on to catch it.

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

You know that feeling you get when you draw the blinds, and you didn’t expect it to be so sunny? That’s what this alarm clock does for you, except it wakes you up instead. Philips incorporated yellow-and-white light into this sunrise simulation programmable alarm clock, and this is the only alarm clock/lamp that’s certified to help you sleep better, and awake more refreshed than you ever thought possible. From America’s favorite retailer of small and budget-friendly gadgets, Philips does it again.

The most accurate mechanical timekeeper is the Shortt pendulum clock; it makes use of the movement described above for electric master clock systems. The Shortt pendulum clock consists of two separate clocks, one of which synchronizes the other. The timekeeping element is a pendulum that swings freely, except that once every half minute it receives an impulse from a gently falling lever. This lever is released by an electrical signal transmitted from its slave clock. After the impulse has been sent, a synchronizing signal is transmitted back to the slave clock that ensures that the impulse to the free pendulum will be released exactly a half minute later than the previous impulse. The pendulum swings in a sealed box in which the air is kept at a constant, low pressure. Shortt clocks in observatories are kept in a room, usually a basement, where the temperature remains nearly constant, and under these conditions they can maintain the correct time to within a few thousandths of a second per day.


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]
Bring contemporary and clean-lined looks to your walls with this understated wall clock, this perfect mix of subtle, airy looks and midcentury modern aesthetics in your space. Featuring a simple rectangular metal frame finished in antique brass and distressed gray, this clock brings a warm look to your ensemble, while its elongated Roman numerals offer an updated twist on a classic look. To clean, simply wipe with a damp cloth.

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A brushed and polished brass finish gives this metal carriage alarm clock its enduring style. The decorative handle, turned brass button feet, and polished brass-tone columns at the corners add to the clock's stately presence. Beneath a glass crystal, the brushed brass-tone dial features circular, diamond-cut numeral ring, black Roman numerals, black hour and minute hands, and brass second and alarm hands.
The returned instants from Clock work on a time-scale that ignores leap seconds, as described in Instant. If the implementation wraps a source that provides leap second information, then a mechanism should be used to "smooth" the leap second. The Java Time-Scale mandates the use of UTC-SLS, however clock implementations may choose how accurate they are with the time-scale so long as they document how they work. Implementations are therefore not required to actually perform the UTC-SLS slew or to otherwise be aware of leap seconds.
A. Many modern alarm clocks are designed to stimulate the natural wake and sleep cycle of the body. Clocks with sunlight simulation help give the body visual cues that it’s time to wake up. Clocks with progressive alarms provide gentle auditory cues. When the body has a chance to wake slowly, it can better prepare for the day, which may help you you feel more rested.
You know that feeling you get when you draw the blinds, and you didn’t expect it to be so sunny? That’s what this alarm clock does for you, except it wakes you up instead. Philips incorporated yellow-and-white light into this sunrise simulation programmable alarm clock, and this is the only alarm clock/lamp that’s certified to help you sleep better, and awake more refreshed than you ever thought possible. From America’s favorite retailer of small and budget-friendly gadgets, Philips does it again.
Not just for keeping your eye on the hour, this eye-catching wall clock lends a touch of retro flair to your ensemble in seconds. Measuring 9.5'' in diameter (so you know it'll fit just about anywhere), this piece pairs a glossy iron frame with a traditional analog dial. This product requires one AA battery to operate, which is not included. The manufacturer for this item provides a limited one-year warranty.
Showcasing the time, date, and weather, this clock is an essential for any desk. No need to lift your arm and look at your watch or light up your phone screen, this 0.3'' H x 3.7'' W x 1.5'' D design is an easy way to get the info you need. A vibrant blue backlight keeps it illuminated (requiring the power of a AA battery), while a plastic frame allows it to stand upright.
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 is the number-one selling kid's clock on Amazon, with more than 2,500 reviews. Parents rave about the restoration of their sleep time. Many parents say it "saved me from my early riser! Life changing!" Even parents of older children with developmental delays found the clock very useful in indicating to non-readers when it's okay to get up, and when it's not.

Sounds like a Marvel villain if you say it out loud, doesn’t it? Sonic Alert Vibrating Skull Crusher Clock has a bit of edge to it, and like your metal days, it’s going to wake you up with a thunderous roar. You get 113 decibels of noise, which is basically like a crappy $20.00 blender whizzing right next to your head. Hook up your phone or MP3 player to rock out to your tunes in the morning, should you dare. You get a five-dimmer setting for the red LED display, and the 12-volt bone crusher bed shaker, just to make sure you’re really awake in the morning.

Alarmclocksonline.com can also be a great place to find a gift for a loved one or a coworker. With our vast assortment of clocks, you can find the perfect gift for whomever it may be. Get your husband that new mp3 dock he's been hoping for, your coworker a nice digital clock to put on his desk, or grandma a new large faced alarm clock so that she can read it without difficulty. The options are endless.


"love it...Not bad...The alarm clock is one of the best I have had, the kids enjoy the extra interactions, and having music anywhere without having to connect my phone to a speaker has been wonderful....I just broadcast a message to them and a glass of water appears in my room LOL I like that it can be controlled from the clock or my phone, so no matter when I am I can broadcast or turn their music down"
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