Harold Black and his three-stage feedback amplifier

Photo of Harold Black on the inset. Photograph of Black's three-stage feedback amplifier. Embodying the principle of negative feedback, these amplifiers were first used in 1936 as repeaters in the coaxial cables between the cities of New York, NY and Philadelphia, PA. Negative feedback made it possible for each amplifier to carry 780 telephone messages simultaneously with great clarity., Credit Line: Bell Laboratories / Alcatel-Lucent USA Inc., courtesy AIP Emilio Segrè Visual Archives, Lillian Hoddeson Collection.
Abstract/Description: Photo of Harold Black on the inset. Photograph of Black's three-stage feedback amplifier. Embodying the principle of negative feedback, these amplifiers were first used in 1936 as repeaters in the coaxial cables between the cities of New York, NY and Philadelphia, PA. Negative feedback made it possible for each amplifier to carry 780 telephone messages simultaneously with great clarity.
Subject(s): Equipment and supplies
Black, Harold S., 1898-1983
Date Created: circa 1936
Credit Line: Bell Laboratories / Alcatel-Lucent USA Inc., courtesy AIP Emilio Segrè Visual Archives, Lillian Hoddeson Collection.
Catalog ID: Black Harold F1
Title: Harold Black and his three-stage feedback amplifier.
Type of Resource: still image
Date Created: circa 1936
Extent: 1 photographic print (black and white; 8 x 10 inches)
Abstract/Description: Photo of Harold Black on the inset. Photograph of Black's three-stage feedback amplifier. Embodying the principle of negative feedback, these amplifiers were first used in 1936 as repeaters in the coaxial cables between the cities of New York, NY and Philadelphia, PA. Negative feedback made it possible for each amplifier to carry 780 telephone messages simultaneously with great clarity.
Identifier(s): Black Harold F1 (Catalog ID)
Note(s):

Credit Line: Bell Laboratories / Alcatel-Lucent USA Inc., courtesy AIP Emilio Segrè Visual Archives, Lillian Hoddeson Collection.
Subject(s): Equipment and supplies
Black, Harold S., 1898-1983
Held by: Niels Bohr Library & Archives
Related Title: Lillian Hoddeson Collection.
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