Stabilized Feedback Amplifiers in Bell Telephone System Monograph B-768, 1934
New York: 1934. 1st Edition. FIRST EDITION OF THE 1st PUBLISHED DESCRIPTION OF H. S. BLACK’S INVENTION OF THE ‘STABILIZED FEEDBACK AMPLIFIER, CONSIDERED BY SOME THE MOST IMPORTANT BREAKTHROUGH OF THE 20th CENTURY IN THE FIELD OF ELECTRONICS GIVEN ITS WIDE AREA OF APPLICATION (Wikipedia). Initially, Black’s idea – feeding a portion of an amplified signal from a later part of a circuit to an earlier part -- was considered “so revolutionary that they found it difficult to accept. Though vacuum tubes and transistors are inherently nonlinear, Black’s work manifest the idea that they can be made to operate in an almost linear fashion through the use of negative feedback. The American patent took nine years to obtain and the British Patent Office treated the invention as they treated applications for patents for perpetual motion machines: they demanded a working model” (Bennett, A History of Control Engineering, 70).
Black’s idea, in his own words, was for “an amplifier whose overall performance is perfectly constant, and whose output distortion constitutes only one hundred millionth of the total energy, although the component parts may be far from linear in their response and their gain may vary over a considerable range… benefits [that] can be obtained by simply throwing away some gain and by utilizing ‘feedback action’” (ibid).
Black first presented the principles of the negative feedback amplifier at a convention of electrical engineers in January of 1934, the first printed presentation of his work appearing, then, in the paper offered here. Interestingly, by the time of Black’s speech and paper, his invention was already seven years old; the principle of his repeater amplifiers had already been well-developed and tested. Both the speech and paper represented the first time information about Black’s work was made public. Part of what this meant was that “the paper was not a tentative account of a new invention, but a succinct and confident description of a maturing device that had passed through difficult years of development and come to practical fruition” (ibid). Item #1383
CONDITION & DETAILS: First edition in original wraps. Bell monographs all come with 3 or 5 hole punches for placement in a binder, here 3. Some staining and chipping at the top edge of the front of the monograph and the first page. Otherwise very good condition.