MAKE A MEME
View Large Image
| View Original: | Hughes_carbon_microphone.png (721x212) | |||
| Download: | Original | Medium | Small | Thumb |
| Courtesy of: | commons.wikimedia.org | More Like This | ||
| Keywords: Hughes carbon microphone.png microphone invented by David Edwards Hughes around 1878 It consists of a horizontal carbon rod M balanced on a fulcrum support A making contact lightly with a carbon block C Sound vibrations made the rod vibrate putting varying pressure on the carbon granules at the contact point causing variation in the resistance When the two wires were connected in a circuit with a telephone receiver and a battery the sounds could be heard from the receiver The pressure at the contact point could be precisely adjusted by the thumbwheel and spring S 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 1878 Retrieved April 8 2015 from https //books google com/books id ezZKAAAAYAAJ pg PA132 Thomas Gray Telephone Encyclopaedia Britannica 9th Edition Charles Scribner's Sons New York 1888 Vol 23 p 132 fig 12 on Google Books Thomas Gray other versions PD-old-70-1923 Uploaded with UploadWizard David Edward Hughes Microphones | ||||
