Elisha Gray patent model telegraph repeater
date: label: date made
content: 1871
name: label: maker
content: Gray, Elisha
notes: label: Description
content: 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.
label: Description
content: This working model was submitted to the U.S. Patent Office by inventor Elisha Gray of Chicago along with his patent application. On 16 May 1871, he received patent #114938 for his "Improvement in Telegraph-Repeaters." Gray's idea, called a "shunt repeater," transferred or "shunted" some of the electrical current to an extra pair of small electromagnets to allow for automatic operation of the repeater. Our records also associate this object with telegraph inventor Charles Haskins although the association is unclear. While Haskins did patent his own repeater whose action was described at the time as "similar to Gray's," patent 114938 was issued to Gray alone and was not assigned to anyone else.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
label: See more items in
content: Communications
label: See more items in
content: Telegraph Relays & Repeaters
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.251262
label: catalog number
content: 251262
label: accession number
content: 48865
label: patent number
content: 114938
objectType: label: Object Name
content: repeater
label: Object Name
content: telegraph relay
label: Object Name
content: telegraph repeater
label: Object Type
content: Patent Model
physicalDescription: label: Physical Description
content: wood (overall material)
label: Physical Description
content: metal (overall material)
label: Physical Description
content: rubber (overall material)
label: Physical Description
content: cloth (overall material)
label: Measurements
content: overall: 4 1/2 in x 13 in; 11.43 cm x 33.02 cm