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.
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.

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Bring home this table clock that showcases an antique-inspired look. Measuring 18'' H x 15'' W x 5'' D, it's the perfect piece to place on a bookshelf or desktop for a practical yet decorative accent. Made in a traditional, alarm-clock inspired style, it features a distressed gray metal frame and feet. Its face displays an off-white background and faded roman numerals, as well as an hour hand, minute hand, and ornamental gears in the center. It accommodates one AA battery to help keep you on...
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.
Get up one minute earlier each and every day. We have biological clocks; it’s not just some weird term we use. Time doesn’t exist. I’m not going to get all existential on you and make you contemplate your place in the universe, because you already know what that is—being the version of you that gets up earlier. Your body needs time to adjust, and if you can wean into it like this, in a month, you’ll be waking up a half-hour early.

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Pairing a simple design with a contrasting black-and-silver palette, this eye-catching 12" wall clock instantly elevates your favorite aesthetic. Its round silhouette blends effortlessly into both casual or formal spaces, while its clean profile adds sophistication to your decor. Lean into this wall clock's versatility by adding it to a transitional living room arrangement alongside a mid-century-inspired sofa and gently-tufted barrel chairs for a cohesive seating space. Anchor the ensemble...
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.
The first precise timekeeping mechanism, whose principles of motion were discovered by Galileo, was the simple pendulum (see below). The accuracy of modern timekeeping has been improved dramatically by the introduction of tiny quartz crystals, whose harmonic oscillations generate electrical signals that may be incorporated into miniaturized circuits…

"Not bad...Love it...This alarm clock is perfect for anyone looking to charger your phone wireless and also has a USB to charger anything you want I have it to charger my gear S3 I also like that it's Bluetooth so I can play music and pick up phone call so I will Recommend this alarm clock to anyone looking to do the same thing I do with it I didn't talk about the alarm it's self because it like any other alarm set it up to Wake you up and it does its job...This is a nice alarm clock and also a decent Bluetooth radio however the reason I picked this up was for the wireless charger for the iPhone X. Regardless of the position the charger flashes on and off in a matter of seconds."


The Electrohome Projection Alarm Clock is the second-best selling alarm clock on Amazon, with more than 9,700 reviews. Many buyers praised the projection feature, and particularly liked the fact that the brightness of the blue LCD display can be adjusted; for some owners, the clock's light is just a little too intense. The ability to set one alarm time for Monday through Friday, and a separate time for the weekend was another popular feature.
“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.”
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