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How an Atomic Clock Really Works: Inside the HP 5061A Cesium Clock

CuriousMarcRecommended by 4 HN commenters across 4 months, 2020–2026
YouTube
explainer · intermediate · evergreen · 2020–2026 on HN

CuriousMarc powers up a vintage HP 5061A cesium beam clock and explains both the quantum principle and the HP implementation in detail. It is part of a longer atomic clock series.

HN calls it one of the best explanations of how atomic clocks actually work.

Electronics & circuit designEveryday physics & science demosHistory of computing#cesiumclock#hp5061a#timekeeping#vintageelectronics

4 comments from Hacker News

@alnwlsn2026-08 · in “Atomic Clocks”

If you want to see how an actual application of this works, I've yet to see a description better than in CuriousMarc's HP 5061A series: ▶ this video

Strongly recommends View on HN
@somat2022-10 · in “Time is an illusion, Unix time doubly so”

CuriousMarc has an excellent episode on an atomic clock. ▶ this video I like to pretend I can fix computers, this guy can actually fix computers, which is probably why I find his show so fascinating.

Strongly recommends View on HN
@puzzledobserver2022-12 · in “The state of the art in amateur timekeeping (2003) [pdf]”

CuriousMarc uploaded a video to Youtube showing the startup procedure for an HP 5061A cesium clock [0]. They switch on the clock and compare it to a GPS reference. Seeing the abstract description realized in concrete terms through hot cesium tubes, phase locked loops, and Lissajous curves was really fascinating. [0] ▶ this video

Recommends View on HN
@kens2020-03 · in “Living Without Atomic Clocks (2016)”

CuriousMarc made a video last week where he uses a vintage HP 5061A atomic clock and explains how it works. It's interesting to see that atomic clocks aren't just some giant laboratory thing, but a product you could buy, even in the 1960s. ▶ this video

Recommends View on HN

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