Clark telegraph repeater patent model
date: label: date made
content: 1860
name: label: maker
content: Clark, James J.
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 non-operating model was submitted to the U.S. Patent Office by inventor James J. Clark of Philadelphia. In July 1860, Clark received patent #29247 for his "Improvement in Telegraphic Repeaters." Clark added an extra magnet to the local circuit of the repeater. Charles Davis and Frank Rae described Clark's repeater in 1877, noting that by then it was obsolete. "The relays have [longer armature levers that respond to extra magnets but] the sounders do the repeating. ... It was very good and was extensively used at one time."
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.251254
label: catalog number
content: 251254
label: accession number
content: 48865
label: patent number
content: 29247
objectType: label: Object Name
content: repeater
label: Object Name
content: telegraph repeater
label: Object Name
content: telegraph relay
label: Object Type
content: Patent Model
physicalDescription: label: Physical Description
content: brass (overall material)
label: Physical Description
content: wood (overall material)
label: Physical Description
content: cloth (overall material)
label: Physical Description
content: ivory (overall material)
label: Physical Description
content: steel (overall material)
label: Physical Description
content: copper (overall material)
label: Measurements
content: overall: 4 in x 12 1/4 in x 12 in; 10.16 cm x 31.115 cm x 30.48 cm