William Duddell

Duddell's devices
Duddell moving-coil oscillograph with mirror in oil bath, Top-Middle: Rotating shutter and moving mirror assembly used with Duddell oscillograph, for placing time-index marks next to the waveform pattern. Top-Right: Moving-film camera for recording the waveform. Bottom: Film recording of sparking across switch contacts, as a high-voltage circuit is disconnected.[1][2][3][4]

William Du Bois Duddell (1 July 1872 - 4 November 1917)^[5] was a British electro-physicist and electrical engineer. He was privately educated in the UK and France and rose quickly through the prestigious City & Guilds Schools via scholarships. His inventions include the moving coil oscillograph, as well as the thermo-ammeter and thermo-galvanometer.

Prior to the invention of the incandescent light bulb, arc lamps were used to light the streets. They created light by means of an electrical arc between two carbon electrodes. These lamps also produced a constant audible hum. Duddell was appointed in 1899 to solve this problem. As a result of his research (through which he demonstrated the humming was caused by a fluctuating electric current), he invented the singing arc, which could generate musical notes by way of a keyboard which interrupted oscillations in a circuit, making it one of the first examples of electronic music, and the very first that did not use the telephone system as an amplifier or speaker.

When Duddell exhibited the singing arc to the London Institution of Electrical Engineers, arc lamps on the same circuit in other buildings were noticed to play the tones of Duddell's machine. Despite the potential of music delivered over the lighting network, Duddell did not capitalize on his discovery as anything more than a novelty.

Duddell was made a Fellow of the Royal Society in 1907.

References

1. ^ Hawkins Electrical Guide, Theo. Audel and Co., 2nd ed. 1917, vol. 6, Chapter 63: Wave Form Measurement, p. 1858, Fig. 2607
2. ^ Hawkins Electrical Guide, Theo. Audel and Co., 2nd ed. 1917, vol. 6, Chapter 63: Wave Form Measurement, p. 1855, Fig. 2620
3. ^ Hawkins Electrical Guide, Theo. Audel and Co., 2nd ed. 1917, vol. 6, Chapter 63: Wave Form Measurement, p. 1866, Figs. 2621-2623
4. ^ Hawkins Electrical Guide, Theo. Audel and Co., 2nd ed. 1917, vol. 6, Chapter 63: Wave Form Measurement, p. 1867, Fig. 2625
5. ^ British Academy; Henry Colin Gray Matthew, Brian Howard Harrison, British Academy (2004). Oxford Dictionary of National Biography: In Association with the British .... Original from the University of Michigan: Oxford University Press. p. 54. isbn=019861411X. http://books.google.com/books?id=MSoYAAAAIAAJ&q=%22William+Duddell%22+1917&dq=%22William+Duddell%22+1917&client=firefox-a&pgis=1. 

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Name	Duddell, William
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Date of birth	1 July 1872
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Date of death	4 November 1917
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