Background
Edwin Henry Colpitts was born on January 9, 1872 in Bute, New Brunswick, Canada. He was the first of eight children of James Wallace Colpitts and Celia Eliza (Trueman) Colpitts.
Edwin Henry Colpitts was born on January 9, 1872 in Bute, New Brunswick, Canada. He was the first of eight children of James Wallace Colpitts and Celia Eliza (Trueman) Colpitts.
Although farming had been the occupation of this English Methodist family for generations, five of the Colpitts children sought scientific or teaching careers. Among them, Julia and Elmer Colpitts both earned Ph. D. 's in mathematics from Cornell and taught at the university level. Planning to pursue a teaching career, Colpitts graduated from normal school at Fredericton, New Brunswick, 1890. A short stint in the schools of Newfoundland changed his plans. Returning to New Brunswick, he entered Mount Allison University and graduated in 1893 with a B. A. in science. He continued his scientific education at Harvard (B. A. , 1896; M. S. , 1897), concentrating in mathematics and physics.
From 1897 to 1899 Colpitts served as an assistant to John Trowbridge, director of Harvard's Jefferson Physical Laboratory. In 1899 Colpitts began his lifelong association with the American Bell Telephone Company, becoming one of the first trained scientists at Bell's Boston laboratory. His work spanned two eras of communications, the electromechanical era (until 1912) and the vacuum tube electronic era (1912 - 1945). In both, his main strength was his rare combination of scientific expertise and practical engineering judgment.
As his three main contributions to the first era show, his strengths were problem-solving and analysis. Applying the concepts of Michael Pupin and G. A. Campbell, his work on new "loading coils" helped extend the range of long-distance telephony. His new methods for measuring the mutual capacitance of neighboring telephone circuits helped reduce the problem of crosstalk. And methods that he devised helped reduce the interference of electric power currents in telephone signals.
By 1912, when Colpitts was director of the Research Laboratories of the Western Electric Company, telephone engineers had exhausted the possibilities of extending the range of long-distance telephony by electrical or mechanical means. To Colpitts and his staff fell the task of adapting Lee De Forest's "audion"--the first triode--for telephone use. The successful accomplishment of this job in 1915 marked the beginning of the electronics age in communications. Colpitts' administrative contribution to this effort was to keep his team focused on the practical problems, dispelling fascination with techniques alone. He invented the Colpitts system of modulation, a key element in the pioneering AT&T radio system, which sent voice messages from Arlington, Va. , to Paris in 1915.
After serving in the U. S. Army Signal Corps in 1917-1918, however, he turned his attention from radio, having underestimated its commercial potential. His last technical efforts were in the field of frequency multiplex telephony (1918 - 1924). As a vice-president of AT&T (1924 - 1934) and Bell Labs (1934 - 1937), he supervised the commercial application of new ideas. Colpitts disdained his most famous invention. In a casual conversation (about 1915) he suggested the principle behind the Colpitts oscillator, a building-block of radio circuitry. He promptly forgot the suggestion and, according to company tradition, had to be persuaded to sign the 1918 patent application that credited it to him.
At his retirement in 1937 he had received twenty-four patents and had published ten technical papers without the dramatic climaxes or disappointments experienced by such communications pioneers as Bell, De Forest, or Reginald Fessenden. World War II added a distinguished postscript to his career. He came out of retirement to serve as head technical aide of Division Six (antisubmarine warfare) of the National Defense Research Committee (1940 - 1946). On March 6, 1949, after a lengthy illness, he died at his home in Orange. He is buried in the family plot at Point de Bute.
Colpitts and scientists under his direction achieved significant advances in the development of oscillators and vacuum tube push–pull amplifiers. In 1915, his team successfully demonstrated the first transatlantic radio telephone. He was awarded the Medal of Merit for his services during World War II.
Colleagues described Colpitts as a man of Yankee temperament, whose strengths were "directness . .. integrity . .. [and] keen analytical intellect, " rather than brilliance or originality.
A niece recalls Colpitts in middle age as tall and quiet, somewhat "crusty on the outside" and tending to impose his own high standards on relatives and associates. Yet he was modest and generous, with a dry sense of humor.
Quotes from others about the person
Frank B. Jewett wrote: "There comes to mind many a picture of Colpitts in the early morning hours, hard at work . .. we find Colpitts in the van, sometimes in the laboratory, but more frequently in rough clothes in the mountains of Pennsylvania or the bush of Georgia . .. always in quest of the facts needed for solution of the problem" (Western Electric Engineer, July 1960, p. 11)
On August 17, 1899, Colpitts married Annie Dove Penney. They had one son, Donald Bethune. After the death of his first wife in March 1940, Colpitts married Sarah Grace Penney.
