RCA / NBC "bullet" condenser microphone
date: label: date made
content: 1925
name: label: maker
content: RCA Corporation
notes: label: Description
content: RCA / NBC condenser microphone. Vertical cylindrical case, cone tope, gauze covered opening at side marked NBC, marked: VIII on bottom, cord attached. A thin, tightly stretched diaphragm of aluminum alloy, spaced 2/1000 inch from flat brass disc form a condenser. The diaphragm, moved by sound waves, varies the capacity of the condenser. Electrical output is feeble but registers faithfully a wider range of input sound, free of the noise evident in carbon microphones. First used regularly in 1925, limited use to 1938. Required amplification close to microphone, but only two stages were feasible at the time.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
creditLine: label: Credit Line
content: from National Broadcasting Company, Inc.
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.311447
label: catalog number
content: 311447
label: accession number
content: 148157
objectType: label: Object Name
content: condenser microphone
label: Object Name
content: radio microphone
label: Object Name
content: microphone
label: Other Terms
content: condenser microphone; Audio Devices
physicalDescription: label: Measurements
content: overall: 8 3/4 in x 4 in x 5 in; 22.225 cm x 10.16 cm x 12.7 cm