Atomic Clocks: What They Are and How They Work

Can atomic clocks set themselves?

Want to set your clock to the correct time? Then you’ll want to set it to an atomic clock. Atomic clocks are the most accurate timepieces in the world and are the standard by which all other timepieces are set. Although several atomic clocks exist around the world, the one used by home automation devices is located outside Boulder, Colorado.

Atomic clock at research lab as well as in a home
Lifewire / Tim Liedtke 

What Is an Home Atomic Clock?

When you purchase a clock that labels itself as an atomic clock, you are buying a device that synchronizes itself to the U.S. government’s official Atomic Clock outside Boulder, Colorado.

Home atomic clocks are designed to receive a radio signal broadcast from the National Institute of Standards and Technology (NIST) in Colorado and to synchronize to that signal.

How to Use an Atomic Clock

Clocks that are synchronized to the NIST atomic clock are simple to use. Once set up, these devices are tuned to the 60kHz radio signal and receive a small binary code that automatically sets the clock to the exact time.

Atomic clock
James Stevenson/Getty Images

Limitations of Atomic Clocks

The majority of home clocks that synchronize to the atomic clock in Boulder, Colorado, only sync within the continental United States and some areas of Canada and Mexico. Atomic clocks will not synchronize correctly in Hawaii, Alaska, and continents other than North America.

Another limitation of home atomic clocks is that they may not receive the NIST signal in large buildings containing steel construction. Move clocks closer to windows in these types of buildings to resolve the synchronization problem.

Atomic Clock Time Sync on Computers

Most computer operating systems automatically synchronize the computer’s clock with NIST time services when the device is connected to the internet. If your computer does not automatically synchronize its clock, there are numerous time synchronization utilities available to enable your computer to do this automatically.

When using a computer interface to control your home automation devices, your devices automatically synchronize themselves to the controller. Using a home automation gateway and the computer’s internet time sync ensures that all home automation devices are operating with NIST time.

If you would like to check the clock on your computer or those in your home, access the official NIST time at

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