audionn.
/ˈɔːdɪɒn/, U.S. /ˈɔdiɑn/, /ˈɑdiɑn/ Radio. Now historical.
An early form of triode valve, developed by Lee De Forest and used as a detector and amplifier for radio signals. Frequently attributive, as audion amplifier, audion tube, etc. De Forest discovered that a signal current flowing through a valve could be varied (modulated) by a second current through a wire placed inside the valve in the path of the signal current through it (in the original form of the audion the wire was wrapped round the outside of the glass envelope). The advantage over earlier devices was that the second current did not have to come from the tuned circuit, enabling this to operate more efficiently. It differed from the later form of the triode in that it was not capable of linear amplification.The device was patented by De Forest in U.S. Patent 824,637 (26 June 1906) and U.S. Patent 836,070 (13 Nov. 1906), but the term audion does not occur in these patents.
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the world > matter > physics > electromagnetic radiation > electronics > electronic devices or components > thermionic valve > [noun] > vacuum tube or thermionic valve
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audion1906
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1906 L. De Forest in Trans. Amer. Inst. Electr. Engineers 25 735 (title) The Audion. A new receiver for wireless telegraphy.
1906 L. De Forest in Trans. Amer. Inst. Electr. Engineers 25 736 This early form of Audion, the flame receiver, was remarkably sensitive to weak high-frequency oscillations.
1915 E. H. Armstrong in Proc. IRE 3 215 (title) Some recent developments in the audion receiver.
1916 Chambers's Jrnl. 63/1 The audion, or wireless lamp, which plays such a part in wireless telephony between Arlington, Hawaii, California, Paris and other distant parts.
1926 Encycl. Brit. New Suppl. I. 838/1 De Forest, Lee..The most important part of his inventions was the Audion amplifier, which made possible long-distance telephony.
1939 Fortune Oct. 116B/1 In 1910 Edwin Armstrong..began tinkering with a vacuum-tube detector—a Fleming valve type, the forerunner of the De Forest audion tube.
1977 J. Monaco How to read Film vi. 353 (caption) The audion tube amplifies a signal because the grid acts as a continually varying electronic gate.
1996 Sci. Amer. (U.K. ed.) Feb. 121/2 Then, voilà..the new Movietone system from Western Electric, incorporating the amplifying power of the audion.
2004 B. Bunch & A. Hellemans Hist. Sci. & Technol. 480/4 1912..Lee De Forest develops the audion amplifier.
This entry has been updated (OED Third Edition, March 2013; most recently modified version published online December 2021).
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n.1906