Stephen Butterworth (1885–1958) was a British

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

who invented the filter that bears his name, a class of electrical circuits that separates

electrical signal In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...

s of different frequencies.

Biography

Stephen Butterworth was born on 11 August 1885 in

Rochdale Rochdale ( ) is a large town in Greater Manchester, England, at the foothills of the South Pennines in the dale on the River Roch, northwest of Oldham and northeast of Manchester. It is the administrative centre of the Metropolitan Borough ...

, Lancashire, England (a town located about 10 miles north of the city of Manchester). He was the son of Alexander Butterworth, a postman, and Elizabeth (maiden name Wynn). He was the second of four children. In 1904, he entered the

Victoria University of Manchester The Victoria University of Manchester, usually referred to as simply the University of Manchester, was a university in Manchester, England. It was founded in 1851 as Owens College. In 1880, the college joined the federal Victoria University. Afte ...

, from which he received, in 1907, both a Bachelor of Science degree in physics (first class) and a teacher's certificate (first class). In 1908 he received a Master of Science degree in physics. For the next 11 years he was a physics lecturer at the Manchester Municipal College of Technology. He subsequently worked for several years at the National Physical Laboratory, where he did theoretical and experimental work for the determination of standards of electrical inductance. In 1921 he joined the Admiralty's Research Laboratory. Unfortunately, the classified nature of his work prohibited the publication of much of his research there. Nevertheless, it is known that he worked in a wide range of fields. For example, he determined the electromagnetic field around submarine cables carrying

alternating current Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...

, and he investigated

underwater explosions An underwater explosion (also known as an UNDEX) is a explosive material, chemical or nuclear explosive, nuclear explosion that occurs under the surface of a body of water. While useful in anti-ship and submarine warfare, underwater bombs are not a ...

and the stability of

torpedoes A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, su ...

. In 1939, he was a "Principal Scientific Officer" at the Admiralty Research Laboratory in the Admiralty's Scientific Research and Experiment Department. During World War II, he investigated both

magnetic mines A naval mine is a self-contained explosive device placed in water to damage or destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, any v ...

and the

degaussing Degaussing is the process of decreasing or eliminating a remnant magnetic field. It is named after the gauss, a unit of magnetism, which in turn was named after Carl Friedrich Gauss. Due to magnetic hysteresis, it is generally not possible to red ...

of ships (as a means of protecting them from magnetic mines). He was a first-rate applied mathematician. He often solved problems that others had regarded as insoluble. For his successes, he employed judicious approximations, penetrating physical insight, ingenious experiments, and skillful use of models. He was a quiet and unassuming man. Nevertheless, his knowledge and advice were widely sought and readily offered. He was respected by his colleagues and revered by his subordinates. In 1942 he was awarded the Order of the British Empire. In 1945 he retired from the Admiralty Research Laboratory. He died on 28 October 1958 at his home in Cowes on the

Isle of Wight The Isle of Wight ( ) is a Counties of England, county in the English Channel, off the coast of Hampshire, from which it is separated by the Solent. It is the List of islands of England#Largest islands, largest and List of islands of England#Mo ...

, England at the age of 73.H. F. Willis, Obituary: "Mr. Stephen Butterworth, O.B.E.," ''Nature'', vol. 182, issue 4651, pages 1706–1707 (1958).

Publications

*S. Butterworth (December 1911) "On the vibration galvanometer and its application to inductance bridges," ''Proceedings of the Physical Society of London'', vol. 24, pages 75–94. *S. Butterworth (December 1911) "A method of measuring small inductances," ''Proceedings of the Physical Society of London'', vol. 24, pages 210–214. *S. Butterworth (December 1912) "On the evaluation of certain combinations of the Ber, Bei and allied functions," ''Proceedings of the Physical Society of London'', vol. 25, pages 294–297. *S. Butterworth (December 1913) "On a null method of testing vibration galvanometers," ''Proceedings of the Physical Society of London'', vol. 26, pages 264–273. *S. Butterworth (December 1914) "On the self-induction of solenoids of appreciable winding depths," ''Proceedings of the Physical Society of London'', vol. 27, pages 371–383. *S. Butterworth (December 1914) "On electrically-maintained vibrations," ''Proceedings of the Physical Society of London'', vol. 27, pages 410–424. *S. Butterworth (December 1919) "On the self-inductance of single-layer flat coils," ''Proceedings of the Physical Society of London'', vol. 32, pages 31–37. *S. Butterworth (December 1919) "The maintenance of a vibrating system by means of a triode valve," ''Proceedings of the Physical Society of London'', vol. 32, pages 345–360. *S. Butterworth (December 1920) "Capacity and eddy current effects in inductometers," ''Proceedings of the Physical Society of London'', vol. 33, pages 312–354. *S. Butterworth (December 1921) "On the use of

Anderson's bridge In electronics, Anderson's bridge is a bridge circuit used to measure the self-inductance of the coil. It enables measurement of inductance by utilizing other circuit components like resistors and capacitors. Anderson's bridge was invented by Ale ...

for the measurement of the variations of the capacity and effective resistance of a condenser with frequency" ''Proceedings of the Physical Society of London'', vol. 34, pages 1–7. *S. Butterworth (December 1921) "Notes on Earth Capacity Effects in Alternating-Current Bridges," ''Proceedings of the Physical Society of London'', vol. 34, pages 8–16. *S. Butterworth (1922) "III. Eddy-current losses in cylindrical conductors, with special applications to the alternating current resistances of short coils," ''Philosophical Transactions of the Royal Society of London, Series A'', vol. 222, pages 57–100. *S. Butterworth (1924) "Note on the alternating current resistance of single layer coils," ''Physical Review'', vol. 23, pages 752–755. *S. Butterworth (1924) "The distribution of the magnetic field and return current round a submarine cable carrying alternating current. Part 2," ''Philosophical Transactions of the Royal Society of London. Series A'', vol. 224, pages 141–184. *S. Butterworth (1 April 1925) "On the alternating current resistance of solenoidal coils," ''Proceedings of the Royal Society of London. Series A'', vol. 107, no. 744, pages 693–715. *S. Butterworth (July 1925) "The high-frequency copper losses in inductance coils", ''Experimental Wireless and the Wireless Engineer'', vol. 2, no. 22, pages 613–616. *S. Butterworth, A. B. Wood, and E. H. Lakey (October 1926) "The use of a resonant shunt with an Einthoven string galvanometer," ''Journal of Scientific Instruments'', vol. 4, no. 1, pages 8–18. *S. Butterworth (1926) "Effective resistance of inductance coils at radio frequencies," ''Experimental Wireless and the Wireless Engineer'', vol. 3, pages 203, 267, 417 and 483. *S. Butterworth (1926) "Designing low-loss receiving coils," ''Wireless World'', vol. 19, pages 754 and 811. *S. Butterworth (January 1929) "The high frequency resistance of toroidal coils," ''Experimental Wireless and the Wireless Engineer'', vol. 6, pages 13–16. *S. Butterworth (November 1929) "Note on the apparent demodulation of a weak station by a stronger one," ''Experimental Wireless and the Wireless Engineer'', vol. 6, no. 74, page 619. *S. Butterworth (1930) "On the theory of filter amplifiers," ''Experimental Wireless and the Wireless Engineer'', vol. 7, pp. 536–541. Available: https://www.changpuak.ch/electronics/downloads/On_the_Theory_of_Filter_Amplifiers.pdf *S. Butterworth and F.D. Smith (1 March 1931) "The equivalent circuit of the magnetostriction oscillator," ''Proceedings of the Physical Society of London'', vol. 43, no. 2, pages 166–185.

Patents

*Stephen Butterworth and Leonard O. Cook, "Suspensions for deflectional instruments". British patent number: GB 433,080 (filed: 25 April 1934; published: 8 August 1935).

Footnotes

{{DEFAULTSORT:Butterworth, Stephen English physicists People from Cowes People from Rochdale 1885 births 1958 deaths