polarized current reverser for telegraphy
name: label: maker
content: Farmer, Moses G.
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: 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 Sarah J. Farmer
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.181959
label: catalog number
content: 181959
label: accession number
content: 2015.0173
objectType: label: Object Name
content: polarized relay
label: Object Name
content: telegraph relay
physicalDescription: label: Measurements
content: overall: 6 in x 4 3/4 in x 9 in; 15.24 cm x 12.065 cm x 22.86 cm