| 释义 |
potentiometer|pəʊtɛnʃɪˈɒmɪtə(r)|
[f. L. potentia power (with allusion to potential n. 4) + -meter.]
1. a. A device for measuring potential difference or an e.m.f. by balancing it against a variable potential difference of known value produced by passing a known (usu. fixed) current through a known (usu. variable) resistance.
1897W. C. Fisher (title) The Potentiometer and its adjuncts. 1906Athenæum 27 Oct. 517/3 The various methods of measuring resistances and a description of the uses of the potentiometer. 1922Glazebrook Dict. Appl. Physics II. 611/2 A Weston cell having an E.M.F. of 1·0183 volts would be balanced across 10 coils and 0·183 of the total length of the slide wire, the pressure drop across each coil of the potentiometer being then 0·1 volt. 1935Turner & Banner Electr. Measurements xi. 127 The Crompton type is one of the most widely used potentiometers; in this, instead of a continuous slide wire covering the whole voltage range, resistance coils are used with a selector switch. 1975D. G. Fink Electronics Engineers' Handbk. xvii. 6 The constant-resistance potentiometer..uses a variable current through a fixed resistance to generate a voltage for obtaining a null with the unknown emf.
b. A voltage divider which is regulated by varying a resistance; also, loosely, a rheostat.
1910G. W. Pierce Princ. Wireless Telegr. xxvii. 324 The accurate adjustment of the local voltage is achieved by the use of a potentiometer. 1914R. Stanley Text-bk. Wireless Telegr. xvi. 221 Such an arrangement of battery and wire is called a potentiometer; by means of it we can obtain any voltage, to apply to our apparatus, from zero up to the full voltage of the battery. 1955Sci. Amer. Aug. 96/2 Connect the power supply to the solution [in the ice-box dishes] through the carbon electrodes and adjust the potentiometer or tapped resistor to the prescribed potential of 200 volts. 1962F. I. Ordway et al. Basic Astronautics ix. 375 The voltage in a current varies with the displacement of the mass by means of a potentiometer. 1966McGraw-Hill Encycl. Sci. & Technol. X. 542/1 By using only the movable and one fixed connection, a potentiometer may be used as a rheostat. 1968A. Marcus Electricity for Technicians iv. 59 Such variable resistors are called rheostats or potentiometers.
2. attrib. and Comb.
1881W. G. Adams in Nature 21 Apr. 582 The electrometer or potentiometer method, in which the difference of potential between two points in the circuit with a given resistance between them is directly measured. 1916C. C. Garrard Electric Switch & Controlling Gear iv. 261 Potentiometer-type regulators are used when it is desired to reduce the voltage applied to the terminals of the field coil to zero, as is the case, for example, with boosters. 1920Whittaker's Electr. Engineer's Pocket-bk. (ed. 4) 434 These curves can be used for any potentiometer regulator which has a resistance 3½ times the field coil. 1922Glazebrook Dict. Appl. Physics II. 615/2 The total resistance of the potentiometer circuit remains unchanged whatever the setting of the dials. 1961G. V. Sadler in G. F. Tagg Pract. Electr. Engin. III. 215 Special precautions must also be taken when potentiometer control is used on a crane whose d.c. supply is obtained from a static rectifier. 1962G. A. T. Burdett Automatic Control Handbk. ix. 4 Potentiometer pressure transducers are made in a number of forms. 1966McGraw-Hill Encycl. Sci. & Technol. X. 543/2 Potentiometer measurement of current is accomplished by passing current through a standardized resistor of appropriate value and measuring the potential difference across this resistor. 1979Sci. Digest July 35/1 When potentiometer controls are used with microprocessor games the analog voltage due to the potentiometer must be converted into a digital quantity.
Hence potentioˈmetric a., of or pertaining to a potentiometer; employing, or obtained by means of, a potentiometer; potentiometric titration, a titration which is followed by measuring the change in potential of an electrode immersed in the sample solution; potentioˈmetrically adv.; potentiˈometry, the technique of measurement with potentiometers, esp. in chemical analysis.
1915Jrnl. Chem. Soc. CVIII. ii. 307 (heading) Potentiometric arrangement for electrochemical investigations. 1926Kolthoff & Furman Potentiometric Titrations viii. 151 Everyone who has had experience with the performance of potentiometric titrations knows that, near the equivalence-point especially,..the potential does not become constant immediately after the addition of the reagent. Ibid. xi. 247 Manganous salts may be titrated potentiometrically according to the Volhard-Wolff method. 1931I. M. Kolthoff Colorimetric & Potentiometric Determination of pH vii. 129 (heading) Problems in potentiometry. 1946L. Michaelis in A. Weissberger Physical Methods Org. Chem. II. xxii. 1052 Potentiometry consists of the measurement of the electro⁓motive force of a galvanic cell composed of two half-cells one of which is a reference half-cell of known composition; and the other an electrode immersed in the solution to be investigated. 1966Elvidge & Sammes Course Mod. Techniques Org. Chem. (ed. 2) xxxiv. 284 Potentiometry makes possible the titration of very weak acids and bases. 1967Times Rev. Industry Oct. 49/3 The length of the cable is then determined by a potentiometric method and may be indicated at any remote control position. 1972Grunwald & Kirschenbaum Introd. Quantitative Chem. Anal. xviii. 337 A silver-silver halide electrode is used for the potentiometric titration of a mixture of halide salts with silver nitrate. 1975D. G. Fink Electronics Engineers' Handbk. x. 13 Potentiometric displacement transducers are widely used because of their relative simplicity of construction and their ability to provide a high-level output. 1978Nature 17 Aug. p. ix/1 Finally the controller starts the titration to titrate the free iodine potentiometrically using sodium thiosulphate. |