Submarine telegraph type 17-B polar relay
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.
setName: label: See more items in
content: Work and Industry: Electricity
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content: Communications
creditLine: label: Credit Line
content: from Western Union International
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.329864
label: accession number
content: 283729
label: catalog number
content: 329864
objectType: label: Object Name
content: telegraph relay
label: Object Name
content: submarine telegraph relay
label: Object Name
content: polar relay