half-waven.adj.
/ˈhɑːfweɪv/, U.S. /ˈhæfˌweɪv/ A. n.
1. Physics and Electronics. One half of a complete cycle of a periodic wave.
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the world > matter > physics > electromagnetic radiation > electricity > electric current > alternating current > [noun] > half-wave of
half-wave1829
the world > matter > physics > electromagnetic radiation > electronics > electronic phenomena > [noun] > waveform > types of waveform > radio waves
carrier1911
ground wave1927
1829 A. Ure New Syst. Geol. i. ii. 41 By hypothesis, they [sc. two waves] differ by a semi-undulation in their pace, the half waves of the one which tend to propel the molecules of the ether forwards, coincide with the half waves of the other which tend to propel them backwards.
1883 Proc. Musical Assoc. (9th Sess., 1882–3) 156 The air on the inside of the tube will take up those same vibrations, and at the lengths of the half-waves will be the nodal points.
1912 Motor Man. (ed. 14) ii. 33 When the platinum contacts at the end of the armature touch, one-half of every complete wave flows into the accumulator, and when the contacts separate, the reverse wave of the current is interrupted at the zero or no-voltage line; thus only the half-waves of current flowing in the same direction are used.
2022 N. D. Jespersen & A. Hyslop Chemistry (ed. 8) vii. 327 The number of nodes is one more than the number of half-waves.
2. A small, curtailed, or tentative wave of the hand. Cf. half adj. 3c.
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1838 N. P. Willis in N.-Y. Mirror 26 May 381/1 The superb daughter of Spinola stepped over the trembling side [of the gondola], and with a half-wave of her hand, strode past the Lion of St. Mark.
1958 H. S. Krech Other Side of Day vi. 101 She smiled over her shoulder and gave a little half-wave.
2006 A. Carter I'd tell you I love you, but then I'd have to kill You (2010) xix. 223 Mrs Abrams raised her hand in a sad half-wave, as if she were freezing that bit of Josh in space and time.
B. adj. Physics and Electronics.
Of a device or instrument operating with light, radio waves, etc.: involving or characterized by an interval of half a wavelength. Cf. full wave adj. at full adj., n.2, and adv. Compounds 1b.
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the world > matter > physics > electromagnetic radiation > electronics > electronic phenomena > [adjective] > of specific wavelength
quarter-wave1872
the world > matter > physics > electromagnetic radiation > electricity > electric current > alternating current > [adjective] > utilizing half waves
half-wave1881
1881 London, Edinb., & Dublin Philos. Mag. 5th Ser. 12 230 A half-wave plate is then interposed in front of the analyzer and rotated until the plane of polarization of the light-rays is not deflected by their passing through the plate.
1904 G. F. Goodchild & C. F. Tweney Technol. & Sci. Dict. 278/1 Half wave plate, a plate of doubly refracting crystal, capable of splitting up a plane polarised ray into two portions, one of which is retarded half a wave length with respect to the other.
1943 Gloss. Terms Telecommunications (B.S.I.) 67 Half-wave dipole, a straight aerial symmetrical in regard to its standing-wave current and usually approximately half a wavelength long.
1962 D. R. Corson & P. Lorrain Introd. Electromagn. Fields xiii. 446 After having mastered the electric dipole, we shall be able to study the radiation field of the half-wave antenna—the type commonly used for transmitting radio waves.
2019 R. A. Chipman et al. Polarized Light & Optical Syst. iv. 95 The orientation of the half wave linear retarder adjusts the orientation of the major axis of each polarization state's ellipse.
Compounds
half-wave rectifier n. Electronics a circuit, device, or component that converts an alternating input into a direct current output by passing current in one direction only.
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1905 Electr. World & Engineer 3 June 1033/1 The half-wave rectifier is described first because it illustrates the principle best.
2000 P. Scherz Pract. Electronics for Inventors iv. 131 This circuit is called a half-wave rectifier, since only half the input waveform is supplied to the output.
half-wave rectification n. Electronics the conversion of an alternating input into direct current output by a circuit, device, or component that passes current in one direction only.
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1915 Gen. Electric Rev. Mar. 164 (caption) Half-wave Rectification, Upper Curve Gives Voltage Over Kenotron.
2020 K. Robinson Pract. Audio Electronics v. 60 One diode on its own easily achieves half wave rectification.
This entry has been updated (OED Third Edition, December 2022).
> as lemmas
half-wave
half-wave n. one-half of a complete wave, esp. of electricity or radiation; freq. attrib., utilizing only alternate halves of a sequence of waves, as half-wave rectification ( Chambers's Techn. Dict. 1940); half a wave-length long, as half-wave antenna, half-wave dipole, etc.
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1904 G. F. Goodchild & C. F. Tweney Technol. & Sci. Dict. 278/1 Half wave plate, a plate of doubly refracting crystal, capable of splitting up a plane polarised ray into two portions, one of which is retarded half a wave length with respect to the other.
1912 Motor Man. (ed. 14) ii. 33 When the platinum contacts at the end of the armature touch, one-half of every complete wave flows into the accumulator, and when the contacts separate, the reverse wave of the current is interrupted at the zero or no-voltage line; thus only the half-waves of current flowing in the same direction are used.
1926 R. W. Hutchinson First Course Wireless viii. 145 If the first half-wave is positive the grid will become positive.
1926 R. W. Hutchinson First Course Wireless viii. 145 The next half-wave is negative and this still further lowers the potential of the grid.
1928 Morning Post 6 Feb. 3/4 A half wave rectifier.
1943 Gloss. Terms Telecommunications (B.S.I.) 67 Half-wave dipole, a straight aerial symmetrical in regard to its standing-wave current and usually approximately half a wavelength long.
1962 J. H. Simpson & R. S. Richards Physical Princ. Junction Transistors xii. 276 The same is true of any amplifier, such as the Class AB, whose output is asymmetrical and consists of pulses that are larger than one half-wave.
1962 D. R. Corson & P. Lorrain Introd. Electromagn. Fields xiii. 446 After having mastered the electric dipole, we shall be able to study the radiation field of the half~wave antenna—the type commonly used for transmitting radio waves.
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n.adj.1829as lemmas