Dynatron oscillator

Dynatron vacuum tube signal generator, 1931. It covered the range 1.8 to 15 MHz. The circuit was used in signal generators due to its frequency stability, which was compared to crystal oscillators
The dynatron oscillator circuit was also used as the local oscillator in early vacuum tube superheterodyne radio receivers, such as this 1931 Crosley model 122 seven tube radio.

In electronics, the dynatron oscillator, invented in 1918 by Albert Hull[1][2] at General Electric, is an obsolete vacuum tube electronic oscillator circuit which uses a negative resistance characteristic in early tetrode vacuum tubes, caused by a process called secondary emission.[3][4][5][6] It was the first negative resistance vacuum tube oscillator.[7] The dynatron oscillator circuit was used to a limited extent as beat frequency oscillators (BFOs), and local oscillators in vacuum tube radio receivers as well as in scientific and test equipment from the 1920s to the 1940s but became obsolete around World War 2 due to the variability of secondary emission in tubes.[8][9][10][11]

Negative transconductance oscillators,[8] such as the transitron oscillator invented by Cleto Brunetti in 1939,[12][13] are similar negative resistance vacuum tube oscillator circuits which are based on negative transconductance (a fall in current through one grid electrode caused by an increase in voltage on a second grid) in a pentode or other multigrid vacuum tube.[5][14] These replaced the dynatron circuit[14] and were employed in vacuum tube electronic equipment through the 1970s.[8][10][11]

  1. ^ Kröncke, H. (March 24, 1926). "Oscillation without reaction" (PDF). Wireless World. 18 (12). London: 467–468. Retrieved March 20, 2015.
  2. ^ Hull, Albert W. (February 1918). "The Dynatron - A vacuum tube possessing negative electric resistance". Proceedings of the IRE. 6 (1). New York: Institute of Radio Engineers: 5–35. doi:10.1109/jrproc.1918.217353. S2CID 51656451. Retrieved 2012-05-06.
  3. ^ Amos, S. W.; Roger Amos (2002). Newnes Dictionary of Electronics. Newnes. p. 107. ISBN 978-0080524054.
  4. ^ Gottlieb, Irving (1997). Practical Oscillator Handbook. US: Elsevier. pp. 76–78. ISBN 978-0080539386.
  5. ^ a b Edson, William A. (1953). Vacuum Tube Oscillators (PDF). US: John Wiley and Sons. pp. 31–34. on Peter Millet's Tubebooks website
  6. ^ Technical Manual TM 11-665: C-W and A-M Radio Transmitters and Receivers. Dept. of the Army, US Government Printing Office. September 1952. pp. 68–69.
  7. ^ Kumar, Umesh (April 2000). "Design of an indiginized negative resistance characteristics curve tracer" (PDF). Active and Passive Electronic Components. 23: 13–23. doi:10.1155/APEC.23.13. Retrieved May 3, 2013.
  8. ^ a b c Dietmar, Rudolph (17 December 2010). "Negative resistance oscillators". Principles of Schematics forum. Ernest Erb personal website. Retrieved 29 November 2013.
  9. ^ Worthen, Charles E. (May 1930). "The Dynatron" (PDF). The General Radio Experimenter. 4 (12). General Radio Co.: 1–4. Retrieved September 5, 2014.
  10. ^ a b Shunaman, Fred (April 1945). "Transitron Oscillators" (PDF). Radio-Craft. 16 (7). New York: Radcraft Publication Inc.: 419. Retrieved September 6, 2014.
  11. ^ a b Palmer, C. W. (March 1940). "Recent advances in oscillator circuits" (PDF). Radio-Craft. 11 (9). New York: Radcraft Publications, Inc.: 534–535. Retrieved September 6, 2014.
  12. ^ Brunetti, C.; E. Weiss (February 1939). "The Transitron Oscillator". Proceedings of the IRE. 27 (2). Institute of Radio Engineers: 88–94. doi:10.1109/JRPROC.1939.229010. ISSN 0096-8390. S2CID 51644322.
  13. ^ Brunetti, Cleto (December 1939). "A Practical Negative Resistance Oscillator". Review of Scientific Instruments. 10 (3): 85–88. Bibcode:1939RScI...10...85B. doi:10.1063/1.1751492.
  14. ^ a b Gottlieb, 1997, Practical Oscillator Handbook, p. 78-81