Farmer telegraph repeater patent model

Description (Brief)
Telegraph repeaters amplified electrical signals in a telegraph line. Telegraph messages traveled as a series of electrical pulses through a wire from a transmitter to a receiver. Short pulses made a dot, slightly longer pulses a dash. The pulses faded in strength as they traveled through the wire, limiting the distance a message could travel. Repeaters remedied that problem by detecting a weak signal and using a local power source to re-energize and re-transmit the signal down the line.
For many years inventors were required to submit models to the Patent Office when they filed for a patent. In 1856, Moses G. Farmer received U. S. patent #14,157 for his “telegraphic repeater”. This is the model Farmer submitted that shows his circuit for an improved way to retransmit telegraph signals. Prior to this invention repeaters had to be switched manually by a telegraph operator. This sometimes led to delays if the operator were otherwise occupied. Farmer's invention allowed for automatic operation of the repeater.
Location
Currently not on view
Object Name
telegraph receiver
telegraph register
telegraph relay
telegraph repeater
date made
1856
maker
Farmer, Moses G.
Physical Description
wood (overall material)
cloth (overall material)
brass (overall material)
steel (overall material)
ivory (overall material)
Measurements
overall: 4 in x 10 in x 12 in; 10.16 cm x 25.4 cm x 30.48 cm
ID Number
EM*308860
catalog number
308860
accession number
89797
patent number
14,157
subject
Communications
Patent Models
Telegraph Relays & Repeaters
See more items in
Work and Industry: Electricity
Telegraph Relays & Repeaters
Data Source
National Museum of American History, Kenneth E. Behring Center
Additional Media

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