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.
Emerson alarm clock radio features relaxing sounds that help you unwind and fall asleep faster. Perfect for bedrooms, baby nurseries, spas, salons, apartments, offices and anywhere where unwanted disturbing or intrusive noise is a problem. The noise sound machine can help block out distractions and promote relaxation prior to sleep to provide you with a more peaceful, restful night sleep. Sounds include ocean side, rain, rain forest, summer night, tide and noise. With features such as a...
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.
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To truly earn its place on your nightstand, an alarm clock should be reliable and versatile, letting you customize your wake-up experience without letting you down. This model is actually more than just an alarm: It has two USB chargers and two outlets. That alone means you and your significant other might fight for who gets to put this clock next to their side of the bed. Thanks to its backup battery, you won’t have a Home Alone oversleeping situation when you need to get to the airport or the power goes out. There’s a big snooze button for those mornings when you need some extra Zs.


“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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