Jump to content

File:Hughes carbon rod microphone 1878.png

Page contents not supported in other languages.
This is a file from the Wikimedia Commons
From Wikipedia, the free encyclopedia

Hughes_carbon_rod_microphone_1878.png (585 × 495 pixels, file size: 62 KB, MIME type: image/png)

Summary

Description
English: Crude carbon rod microphone invented by David Edwards Hughes in 1878. It consists of a carbon rod (A) suspended by its pointed ends vertically between two metal electrodes (C). Sound vibrations transmitted from the wooden back (B) to the carbon-steel contact causes varying pressure on the carbon granules, causing variation in the carbon's resistance. Edwards found that the device was very sensitive, he was able hear the sound of a fly walking on it, and named it "microphone". Edwards did not invent the microphone but experimented with a wide range of "microphonic" electrical contacts. With another type of contact he discovered he could detect electromagnetic waves from a spark, thus inventing a type of coherer.
Date
Source Retrieved April 8, 2015 from Thomas Gray, "Telephone", Encyclopaedia Britannica, 9th Edition, Charles Scribner's Sons, New York, 1888, Vol. 23, p. 132, fig. 11 on Google Books
Author Thomas Gray

Licensing

Public domain
Public domain
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.

United States
United States
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.

Captions

Add a one-line explanation of what this file represents

Items portrayed in this file

depicts

File history

Click on a date/time to view the file as it appeared at that time.

Date/TimeThumbnailDimensionsUserComment
current18:34, 9 April 2015Thumbnail for version as of 18:34, 9 April 2015585 × 495 (62 KB)ChetvornoUser created page with UploadWizard

The following page uses this file:

Global file usage

The following other wikis use this file:

Metadata