File:Pancake oscillation transformer.jpg
Jump to navigation
Jump to search
Size of this preview: 578 × 599 pixels. Other resolutions: 231 × 240 pixels | 463 × 480 pixels | 872 × 904 pixels.
Original file (872 × 904 pixels, file size: 85 KB, MIME type: image/jpeg)
Captions
Captions
Add a one-line explanation of what this file represents
Summary
[edit]
| Description |
English: A radio frequency "oscillation transformer" used in a spark-gap radio transmitter from 1913. It consists of two spirals of brass strip mounted on a support rod facing each other so they are magnetically coupled. One coil is connected to a capacitor, making a tuned circuit (tank circuit). The other coil is connected to the antenna and ground. When excited by high voltage from a spark gap, charge flows back and forth between the plates of the capacitor through the primary coil, creating radio frequency oscillations. The magnetic field of the primary coil induces RF voltage in the secondary coil, which is radiated from the antenna as radio waves. The inductance can be changed by moving the adjustable terminals up or down on the spiral, to tune the resonant frequency. The coupling between the coils can be adjusted by moving the top coil up or down along the support rod.
The spiral construction is used to reduce losses at radio frequencies due to proximity effect. A wide strip is used to give the conductor a large surface area, which reduces resistive losses due to skin effect. Spiral coils like this are still used today in modern long wave radio transmitters. |
| Date | |
| Source | Retrieved November 14, 2013 from Alfred Powell Morgan (1913) The Boy Electrician, Lothrop, Lee, and Shepard Co., Boston, facing p. 270 on Google Books |
| Author | Alfred Powell Morgan |
Licensing
[edit]
 |
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.
|
 |
 |
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.
|
File history
Click on a date/time to view the file as it appeared at that time.
| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 10:52, 20 January 2014 | | 872 × 904 (85 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
You cannot overwrite this file.
File usage on Commons
There are no pages that use this file.
