File:D'Arsonval ammeter movement.jpg
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Summary
| Description |
English: Drawing of D'Arsonval Galvanometer (ammeter) movement, of Weston type, from around 1900. This is the mechanism used in most moving-pointer (galvanometer) meters today. Only the pole pieces of the horseshoe-shaped magnet are shown, and part of the left-hand pole piece is broken out by the artist to show the coil. It consists of a light coil of wire with an attached pointer, suspended on jewel bearings between the poles of a magnet, with a spiral hairspring to return it to zero. When a current is passed through the coil, it creates a magnetic field that opposes the magnet's field, creating a torque that rotates the coil against the restoring force of the spring. The coil turns through an angle until the restoring force of the spring is equal to the force of the coil. Since the angle of deflection is proportional to the force, which is proportional to the current, the deflection is proportional to the current. The screwdriver slot at the top of the axis is for adjusting the meter to zero. Alterations: removed caption, and faint background discoloration. |
| Date | |
| Source | Downloaded from Flather, John J. (1900) Dynamometers and the Measurement of Power, 2nd Ed., John Wiley & Sons, New York, p.236, fig.81 on Google Books. The drawing is signed 'Bartlett & Co. N.Y.' |
| Author | Bartlett & Co. N.Y. |
| Permission (Reusing this file) |
Public domain - published in US before 1923 |
Licensing
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This media file is in the public domain in the United States. This applies to U.S. works where the copyright has expired, often because its first publication occurred prior to January 1, 1929, and if not then due to lack of notice or renewal. See this page for further explanation.
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This image might not be in the public domain outside of the United States; this especially applies in the countries and areas that do not apply the rule of the shorter term for US works, such as Canada, Mainland China (not Hong Kong or Macao), Germany, Mexico, and Switzerland. The creator and year of publication are essential information and must be provided. See Wikipedia:Public domain and Wikipedia:Copyrights for more details.
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 20:16, 10 December 2007 | | 844 × 785 (75 KB) | Chetvorno | {{Information |Description=Drawing of D'Arsonval ammeter movement. |Source=Downloaded from [http://books.google.com/books?id=lFcEAAAAMAAJ&pg=PA236 Flather, John J. (1900) ''Dynamometers and the Measurement of Power, 2nd Ed.'', John Wiley & Sons, New York |
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