Miniature box telegraph relay
date: label: date made
content: 1900
notes: label: Description
content: Telegraph relays 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, to the point where the incoming signal was too weak to directly operate a receiving sounder or register. A relay detected a weak signal and used a battery to strengthen the signal so that the receiver would operate.
label: Description
content: Box relays were most often used by linemen or station operators for testing purposes or where a local battery was not available. The covering box acted as a resonator that amplified the sound of the relay’s light-weight armature, making the signal audible without a sounder. This unusual miniature unit was made by the donor and was reportedly used briefly on the line between Pittsburgh and Baltimore.
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
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content: Telegraph Relays & Repeaters
creditLine: label: Credit Line
content: from C. I. Ways
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.313149
label: catalog number
content: 313149
label: accession number
content: 177205
objectType: label: Object Name
content: relay
label: Object Name
content: telegraph relay
physicalDescription: label: Physical Description
content: wood (overall material)
label: Physical Description
content: steel (overall material)
label: Physical Description
content: brass (overall material)
label: Physical Description
content: cloth (overall material)
label: Measurements
content: overall: 2 in x 5 1/2 in x 2 1/4 in; 5.08 cm x 13.97 cm x 5.715 cm