File:Vacuum electrode electrotherapy treatment 1930s.jpg
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English: Vacuum electrode electrotherapy treatment of elbow in 1930s. Electrotherapy was a Victorian era medical field, mostly quack medicine, in which high voltage alternating current was applied to the body to treat a variety of ailments. The vacuum electrode applicator consists of a metal electrode sealed inside a partially evacuated glass bulb, which is connected by a wire to the high voltage terminal of a Tesla coil or Oudin coil. The high voltage radio frequency alternating current, 50,000 to 500,000 volts at 100 kHz to 2 MHz, passed from the electrode through the ionized gas into the patient's body. This wasn't painful for the patient because alternating currents over 10 kHz frequency do not cause the sensation of electric shock. The glass wall of the bulb formed a capacitor which served to limit the current. The high voltage ionized the gas, creating a mysterious violet glow in the bulb (not visible here), which impressed patients. Electrotherapy had its heyday after World War 1, around 1920, but declined and had virtually disappeared by the time this book was published, 1945 |
| Date | |
| Source | Retrieved October 2, 2015 from Richard Kovács (1945) Electrotherapy and Light Therapy, 5th Ed., Lea and Febiger, Philadelphia, p. 242, fig. 183 on https://archive.org/ |
| Author | Richard Kovács |
| Permission (Reusing this file) |
This 1945 book would have the copyright renewed in 1973. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. Search of the Renewals for 1972, 1973, and 1974 show no renewal entries for Electrotherapy and Light Therapy. Therefore the copyright was not renewed and it is in the public domain. |
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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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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 11:45, 19 October 2015 | | 419 × 224 (21 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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