Western Electric D-12020 polar telegraph relay
date: label: date made
content: ca 1920
name: label: Maker
content: Western Union Corporation
label: maker
content: Western Electric
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.332473
label: model number
content: D-12020
label: accession number
content: 294351
label: catalog number
content: 332473
objectType: label: Object Name
content: polar relay
label: Object Name
content: relay
label: Object Name
content: telegraph relay
physicalDescription: label: Measurements
content: overall: 5 in x 4 3/4 in x 5 1/2 in; 12.7 cm x 12.065 cm x 13.97 cm