Siemens polar telegraph relay
date: label: date made
content: 1877
name: label: maker
content: Siemens
label: maker
content: Phelps
notes: label: Description
content: Telegraph relays amplify an electrical signal in a telegraph line. Telegraph messages travel as a series of electrical pulses through a wire from a transmitter to a receiver. The pulses fade in strength as they travel through the wire, limiting the distance a message can be sent. Relays remedy that problem by detecting a weak signal and automatically re-transmitting that signal down the line using a local power source.
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
creditLine: label: Credit Line
content: from Western Union Corporation
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.331679
label: accession number
content: 294351
label: collector/donor number
content: 100-054
label: catalog number
content: 331679
label: collector/donor number
content: 15-08
objectType: label: Object Name
content: polar relay
label: Object Name
content: telegraph relay
physicalDescription: label: Physical Description
content: brass (part: material)
label: Physical Description
content: wood (part: material)
label: Physical Description
content: steel (part: material)
label: Physical Description
content: glass (part: material)
label: Measurements
content: without base: 4 3/4 in x 6 3/4 in; 12.065 cm x 17.145 cm
label: Measurements
content: overall: 5 1/2 in x 11 in x 9 3/4 in; 13.97 cm x 27.94 cm x 24.765 cm