RCA NBC "bullet" condenser microphone

RCA / NBC "bullet" condenser microphone

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Description
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.
Location
Currently not on view
Object Name
condenser microphone
radio microphone
microphone
Other Terms
condenser microphone; Audio Devices
date made
1925
maker
RCA Corporation
Measurements
overall: 8 3/4 in x 4 in x 5 in; 22.225 cm x 10.16 cm x 12.7 cm
ID Number
EM.311447
catalog number
311447
accession number
148157
Credit Line
from National Broadcasting Company, Inc.
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Work and Industry: Electricity
Data Source
National Museum of American History
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