model WM 225-A polar telegraph relay
name: label: Maker
content: Western Union Corporation
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.332477
label: model number
content: WM 225-A
label: accession number
content: 294351
label: catalog number
content: 332477
objectType: label: Object Name
content: polar relay
label: Object Name
content: relay
label: Object Name
content: telegraph relay
physicalDescription: label: Measurements
content: overall: 2 3/4 in x 1 5/8 in x 1 5/8 in; 6.985 cm x 4.1275 cm x 4.1275 cm