File:Marrisons quartz crystal clock.jpg
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Summary
| Description |
English: One of the first experimental quartz clocks, invented by physicist Warren Marrison around 1927 at Bell Telephone Laboratories. It keeps time with an electronic oscillator controlled by the quartz crystal under the dome vibrating at 100 kilohertz. The clock's signal is divided down in frequency by vacuum tube counters, and controls the synchronous electric clock on the front. The caption states it keeps time to better than one hundredth of a second per day |
| Date | May 1931 |
| Source | Retrieved 14 May 2024 from Electronics magazine, McGraw-Hill Co., New York, Vol.2, No.5, May 1931, p.652 without attribution. This publication's copyright would have been renewed in 1959. The Online Books record of copyright renewals for Electronics lists no renewals. Therefore it was not renewed and is in the public domain |
| Author | Unknown author |
Licensing
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This work is in the public domain because it was published in the United States between 1929 and 1963, and although there may or may not have been a copyright notice, the copyright was not renewed. For further explanation, see Commons:Hirtle chart and the copyright renewal logs. Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.
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File history
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 00:42, 15 May 2024 | | 589 × 521 (88 KB) | Chetvorno | Uploaded a work by {{Unknown|author}} from Retrieved 14 May 2024 from [https://www.worldradiohistory.com/Archive-Electronics/30s/Electronics-1931-05.pdf Electronics magazine, McGraw-Hill Co., New York, Vol., No., May 1931, p.652] without attribution. This publication's copyright would have been renewed in 1959. The [https://onlinebooks.library.upenn.edu/webbin/cinfo/electronics Online Books record of copyright renewals for Electronics] lists no renewals. Therefore it was not renewed and... |
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