File:Airplane Detection Appt002.jpg
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| Description |
Three-stage amplifying set device for detecting airplanes, Acoustic Laboratory, Frankford Arsenal, open. Operation [top]: 1. Connect condenser detector to input.; 2. Connect telephone to output.; 3. Decrease grid leaks to minimum resistance.; 4. Set filament controls at OFF position.; 5. Turn on A Battery by pulling out snap switch.; 6. Increase filament current of last tube to almost full value.; 7. Set filament control knobs of other tubes to index marks. (Never turn past these marks.); 8. Increase grid leak resistance until maximum amplification is obtained.; 9. No further attention is required. |
| Date | |
| Source | National Institute of Standards and Technology |
| Author | National Institute of Standards and Technology |
| Permission (Reusing this file) |
The images in the Airplane Detection Apparatus Photographic Collection are in the public domain and are not subject to copyright in the United States. However, please pay special attention to the individual works to make sure there are no copyright restrictions indicated. Individual works may require securing other permissions from the original copyright holder. Use of the images from NIST Digital Collections is not restricted, but a statement of attribution is required. Please use the following attribution statement: "National Institute of Standards and Technology Digital Collections, Gaithersburg, MD 20899." |
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This work is in the public domain in the United States because it is a work prepared by an officer or employee of the United States Government as part of that person’s official duties under the terms of Title 17, Chapter 1, Section 105 of the US Code.
Note: This only applies to original works of the Federal Government and not to the work of any individual U.S. state, territory, commonwealth, county, municipality, or any other subdivision. This template also does not apply to postage stamp designs published by the United States Postal Service since 1978. (See § 313.6(C)(1) of Compendium of U.S. Copyright Office Practices). It also does not apply to certain US coins; see The US Mint Terms of Use.
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| This file has been identified as being free of known restrictions under copyright law, including all related and neighboring rights. | ||
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
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| current | 19:11, 16 April 2014 | | 4,852 × 5,937 (1.41 MB) | NISTResearchLibrary (talk | contribs) |
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