Harold J. Paz
Harold Joseph Paz (April 11, 1929) is the co-inventor of the Direct-coupled amplifier. It displaced the triode vacuum tube amplifier designed by Lee de Forest. Almost all vacuum tube circuit designs are now replaced with direct coupled transistor circuit designs. It is the first transistor amplifier design that did not include coupling capacitors. Paz and his co-inventor Francis P. Keiper Jr. filed for their patent on February 13, 1955, which was awarded on April 17, 1962[1]. The direct-coupled amplifier allowed analog circuits to be built smaller with the elimination of coupling capacitors and removed the lower frequency limitation that is dependent on capacitors.
Early life
Paz was born on April 11, 1929, in Brooklyn, New York, to Joseph and Mary Paz. He is the youngest of three siblings, William Paz and Candida Lozada. Paz graduated with a BS in Electrical Engineering from Brooklyn Polytechnic Institute in 1954[2].
Career
Bell Labs
Paz's first internship was at Bell Labs from December 1950 to April 1952 as an Engineering Aid. Paz worked on testing several transistor parameters, such as rise time, RC timing constant, and alpha coefficient, to determine their effects on a transistor circuit design.
RCA
Paz began working at RCA as a summer student engineering intern from June 1953 to September 1953. Paz was assigned to determine the effects of several variables on a transistor's noise factor at various radio frequencies. It was the result of this research that Paz designed the first transistor-based wireless microphone, called Phantom. RCA took interest in Paz's design and made their subsidiary National Broadcasting Company aware of the new microphone. RCA decided to file patent US2,810,110 for the microphone on July 16, 1954, and it was granted on October 15, 1957. The design was used for the ND-433 wireless microphone that NBC used in 1955.
Philco
In June 1954, Paz took an engineering position at Philco and was assigned to the Transistor Product Engineering Group to study the theory of operation of the direct-coupled switching circuits of R. Brown. The switching circuits used one resistor per transistor, which was revolutionary at the time for its low component count. Transistors were primarily used as an on-off digital device that would be beneficial for making a solid-state digital computer. It was after understanding the theory of the switching circuits that Paz invented the direct-coupled "Triplet", which is a three-stage linear amplifier that uses only one resistor per transistor amplification stage. It was during this time that Paz was introduced to Robert Noyce, who was also in the Transistor Research Department. The direct-coupled amplifier was influential in the development of Fairchild's uA709 operational amplifier by Bob Widlar, which Noyce knew about as he was one of the founders of Fairchild Semiconductors.
The direct-coupled amplifier is also the basis for Philco's Mark I hearing aid, which used the circuit built with silicon alloy transistors. The hearing aid was listed as Figure 5 as an application of the Triplet on the US3030586 patent[1].
Paz left Philco in August 1955.
RCA and publications
In August 1955, Paz returned to RCA to work on designing a power supply that used small transistors which could regulate and control a large amount of power. This research resulted in new circuitry that Paz designed and was featured in RCA's internal academic journal, the Industry Service Laboratory[3]. Paz later published his design with the International Radio Engineers and presented his findings at the IRE convention in 1957.
Paz continued working on various transistor amplifier designs for RCA, including a transistor circuit design that could be used in the rack mounted amplifier product line. This transistor circuit became a transistor preamplifier equalizer for professional turntables. Paz submitted his paper at the 1957 Annual Audio Engineering Convention[4]. Additional products include the "hybrid" transistor power amplifier, which was the first 10 watt amplifier with less than 0.333% distortion from 30 cycles to 15,000 cycles. It was also compatible to be used with any RCA 2N301 power transistors. The low distortion transistor power amplifier was published in the Electronics Industries magazine[5] and Paz presented his findings at the National Convention of IRE in 1959[6].
Personal life
Paz was working at RCA when he met Florence McKenna while on a company vacation in Florida. McKenna was the secretary for Paz's division. Paz and McKenna married on September 21, 1963, at St. Matthew's Church in National Park, New Jersey. They had three children, Lisa, Linda, and Carol.
Paz currently resides in Tampa, Florida.
References
- ↑ 1.0 1.1 US3030586A, Paz, Harold J. & Francis P. Jr. Keiper, "Transistor circuit", issued 1962-04-17
- ↑ Paz, Harold (1954-06-16), English: Graduating Electrical Engineering Class of 1954 from Polytechnic Institute of Brooklyn (PDF), retrieved 2022-03-05
- ↑ Paz, Harold (1956). "A Phase -Regulated Transistor Power Supply" (PDF). RCA Technical Papers. IV: 23 – via One Electron.
- ↑ Paz, Harold (October 1, 1957). "Transistorized Preamplifier for Professional Turntables". Journal of Audio Engineering Society. 5: 10 – via AES E-Library.
- ↑ "RADIO / BROADCAST HISTORY LIBRARY: Thousands of magazines & Publications ALL FREE". worldradiohistory.com. Retrieved 2022-04-06.
- ↑ "1959 IRE National Convention Program". Proceedings of the IRE. 47 (3): 10. 1959-03-23. doi:10.1109/JRPROC.1959.287224. ISSN 2162-6634 – via IEEE.
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