vacuum tube
1. An evacuated tube or pipe, esp. one along which vehicles or other objects can be propelled by allowing air to enter behind them.
| 1784 in Pall Mall Mag. (1896) Aug. 586 Grand Vacuum Tube Company. Direct to Bengal. 1846 Patent Jrnl. 4 July 90/1 Fig. 1 is a..section of a railway carriage and traction tube. Fig. 2 is a cross section..showing the communication between the carriage and the piston. The traction or vacuum tube..is the same as generally used. 1920 D. H. Lawrence Touch & Go 7 A system of vacuum tubes for whooshing Bradburys about from one to the other. 1972 Daily Tel. 30 Dec. 6/5 The explanation, it is believed, is that while it was being scooped up it became mixed with the dark grey soil usually found on the Moon. It could not have changed as a result of exposure to the Earth's atmosphere, because it is stored in vacuum tubes. 1973 Times 15 Oct. 6/3 High-speed surface systems should be studied as an alternative to air travel, including advanced systems such as the gravity vacuum tube, which would give high speeds for amazingly low energy consumption. 1974 [see people mover s.v. people n. 8]. |
2. An evacuated tube (sense 2 g) (
orig. a glass cylinder);
spec. one used as a thermionic valve.
| 1859 Phil. Trans. R. Soc. CXLVIII. 15 The direct discharge is that which is visible when taken from two wires hermetically sealed in a vacuum tube. 1880 Rep. Brit. Assoc. Adv. Sci. 1880 260 The band-spectrum of nitrogen... It was first observed by Plücker (1858) in a vacuum tube. 1901 Engineer 17 May 507/2 One of the most interesting exhibits was a number of electric vacuum-tube lamps. 1915 W. H. Eccles Wireless Telegr. & Teleph. 376 A. Langmuir has applied his vacuum tube with third electrode (the ‘pliotron’) in a manner different from those just described. 1923 Electr. Communication II. 157/2 No single advance has contributed so largely to change our whole picture of art as the advent of the thermionic valve or vacuum tube as it is designated in America. 1931 Moyer & Wostrel Radio Handbk. vi. 317 The increased use of vacuum tubes for other than radio services has made it necessary to design vacuum tubes which will be suitable for handling much larger currents. 1957 K. R. Spangenberg Fund. Electron Devices xi. 235 The transistor is, like the vacuum tube, a device that owes its amplifying characteristics to electric-field control of current within the device. 1972 Sci. Amer. June 52/2 It produces a television-like image without the cumbersome vacuum tube, electron beam and high voltage required by conventional television systems. |
| attrib. 1923 Electr. Communication II. 157/2 The vacuum tube telephone repeater has made possible telephonic transmissions over practically unlimited distances. 1929 K. Henney Princ. Radio xiv. 343 Such vacuum tube voltmeters are useful at all audio and nearly all radio frequencies, and can be made to read d.-c. voltages. 1950 [see instrument n. 2]. |