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Summary
| Description |
English: Advertisement by Jensen Radio Manufacturing Co. in 1945 for speakers made with Alnico 5 magnets, a new type of permanent magnet which had been developed during World War 2. As illustrated in the ad Alnico 5, the most powerful magnet yet developed, allowed a dramatic reduction in the size of speaker magnets from 98 ounces in 1930 to 4.65 oz. Alnico remained the most powerful type of permanent magnet until rare earth magnets were developed in the 1980s. |
| Date | |
| Source | Retrieved June 12, 2014 from Radio News magazine, Ziff-Davis Publishing Co., New York, Vol. 33, No. 4, April 1945, p. 7 on American Radio History site |
| Author | Unknown author |
| Permission (Reusing this file) |
This image is from an advertisement for Jensen Co. without a copyright notice published in a 1945 magazine. In the United States, advertisements published in collective works (magazines and newspapers) are not covered by the copyright notice for the entire collective work. (See U.S. Copyright Office Circular 3, "Copyright Notice", page 3, "Contributions to Collective Works".) Since the advertisement was published before 1978 without a copyright notice, it falls into the public domain. |
Licensing
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This work is in the public domain in the United States because it was published in the United States between 1929 and 1977, inclusive, without a copyright notice. For further explanation, see Commons:Hirtle chart as well as a detailed definition of "publication" for public art. 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 (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 15:35, 15 July 2023 | | 2,159 × 3,055 (1.02 MB) | JanTH | use clean version without a PDF viewer toolbar visible in the picture |
| 10:52, 16 June 2014 |  | 1,090 × 1,550 (345 KB) | Chetvorno | User created page with UploadWizard |
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