It used a carbon transmitter, so that the hearing aid could be portable.
2.
Bell adopted carbon transmitters similar to Edison's transmitters and adapted telephone exchanges and switching plug boards developed for telegraphy.
3.
The carbon transmitter was used to amplify sound by taking a weak signal and using electric current to make it a strong signal.
4.
Most all-electronic telephones need at least three volts DC to work, and so will often become useless in such situations, whereas carbon transmitter telephones will continue to work down to a fraction of a volt.
5.
A recent history of telephones states that the carbon transmitter used in early 20th century telephones was based on Edison's carbon transmitter, as modified by Bell system engineer AC White in 1890 . talk ) 16 : 24, 27 December 2011 ( UTC)
6.
A recent history of telephones states that the carbon transmitter used in early 20th century telephones was based on Edison's carbon transmitter, as modified by Bell system engineer AC White in 1890 . talk ) 16 : 24, 27 December 2011 ( UTC)
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