| 释义 |
cathode Electr.|ˈkæθəʊd|
Also kath-.
[ad. Gr. κάθοδος a going down, way down, f. κατά down + ὁδός way.]
a. The path by which an electric current leaves the electrolyte and passes into the negative pole; the point or surface in contact with the negative pole; in electro-metallurgy the object to be electro-plated.
b. The negative pole. Opposed to anode: see electrode.
1834Faraday Res. Electr. (1839) §663 The cathode is that surface at which the current leaves the decomposing body, and is its positive extremity. 1839Proc. Amer. Phil. Soc. I. 100 The lower electrode formed the cathode. 1870R. Ferguson Electr. 161 The poles..are called electrodes..the - pole being called the cathode. 1875Ure Dict. Arts II. 219 The deposit was formed in twenty-four hours upon the whole of the cathode. 1881Metal World No. 9. 131 The object to be coppered is to be..attached as a cathode..when it will become rapidly coated with an adherent film of metallic copper. 1883E. H. Gordon Electr. & Magn. (ed. 2) II. 1 The electrode attached to the zinc of the battery is called the cathode, and the other, the anode.
c. attrib. and Comb. cathode dark space = Crookes (dark) space; cathode follower, a type of electric circuit (see quots.); also attrib.; cathode ray, a beam of electrons issuing from the cathode of a high-vacuum tube under the action of an electric field; hence cathode-ray oscillograph: see oscillograph and quot. 1922; cathode-ray oscilloscope (see quot.); cathode-ray tube, a vacuum tube in which cathode rays are projected upon a fluorescent screen.
1914R. Soc. Catal. Sci. Papers 1800–1900, Subject Index III. ii. 685/2 Cathode dark space, origin. 1920Discovery July 217/1 The dark space around the negative pole, which has since been referred to as the Crookes or Cathode Dark Space.
1939Electronics Mar. 35 Connections of the cathode-coupled (‘cathode-follower’) stage, used for low-impedance output applications. 1941Wireless World July 176/1 In essence, the cathode-follower stage is a device to avoid mismatching. Ibid. 177/1 The cathode-follower gives an output voltage equal to its input voltage (the cathode potential follows the grid potential—hence the name ‘cathode-follower’). 1942Electronic Engin. XV. 287 The ‘cathode follower’ type of circuit has the distinction of being one of the most versatile circuits used by the Radio Engineer..and derives its name from the fact that an input signal that makes the grid go positive with respect to HT. negative will also make the cathode go positive with respect to HT. negative.
1905Jrnl. Chem. Soc. LXXXVIII. ii. 224 With copper, nickel, gold, and bright platinum, the cathode potential for a given current density goes on increasing for hours.
Ibid., Cathode process and anode liquid are opposed to each other.
[1879Phil. Trans. R. Soc. CLXX. 144 It excludes such rays of the cathode as impinge upon it from reaching the side.] 1880Phil. Mag. X. 411 It was further examined whether the negative discharges which excite the green light, the so-called kathode-rays, do really propagate themselves only in straight lines. 1898[see corpuscle 2 c]. 1900Jrnl. Chem. Soc. LXXVIII. ii. 587 Electrical Conductivity in Gases traversed by Cathode Rays. 1912J. W. Mellor Mod. Inorg. Chem. xliii. 825 The cathode rays is [sic] a stream of negatively charged electrons sent from the cathode with a high velocity. 1951J. R. Partington Gen. & Inorg. Chem. (ed. 2) viii. 184 These cathode rays were discovered in 1859 by Plücker, who showed that they are easily deflected by a magnet. 1957Encycl. Brit. V. 41/1 Cathode rays have many applications, one of the chief being the excitation of X-rays by the impinging of swift electrons against a hard anticathode.
1922Glazebrook Dict. Appl. Physics II. 146/2 Cathode ray oscillograph, an apparatus for delineating the instantaneous values of the current or voltage in a circuit by the deflection of a fine cathode stream. 1937Discovery Jan. 4/1 A cathode ray oscillograph..is an instrument in which a fast beam of electrons passes between deflecting plates and impinges on a screen, where it produces a spot of light. 1951Uvarov & Chapman Dict. Science (ed. 2) 44 Cathode ray oscilloscope, apparatus consisting essentially of an ‘electron gun’ producing a beam of electrons which passes through horizontal and vertical deflecting plates, to fall upon a fluorescent screen.
1905Varley & Murdoch in Electrician 16 June 335/1 (title) Some Applications of the Braun Cathode-Ray Tube. 1934Discovery Apr. 106/1 The advances made in the use of short waves and the introduction of cathode-ray tubes have enabled us to transmit images on screens 3 or 4 feet square. 1957Amos & Birkinshaw Television Engin. I. ix. 210 In the majority of television receivers the picture is produced on the face of a cathode-ray tube which is viewed directly or by reflection at a plane mirror. |