| 释义 |
ˈoverˌvoltage
[f. over- 19, 20 + voltage2, as tr. G. überspannung (W. A. Caspari 1899, in Zeitschr. f. physikal. Chem. XXX. 91).]
1. The difference between the electrode potential for a reaction (as the liberation of a gas) in practical, irreversible conditions and the theoretical, reversible value.
1907Whitney & Brown tr. Le Blanc's Text-bk. Electro-Chem. viii. 299 Not only in the case of hydrogen, but also in that of oxygen, an over-voltage which varies with the nature of the electrode..is produced by the separation of the gas. 1922Glazebrook Dict. Appl. Physics II. 60/1 Platinised platinum as a cathode has the lowest overvoltage among the elements commonly available. 1965Phillips & Williams Inorg. Chem. I. xi. 421 Using a mercury electrode the over-voltage of hydrogen is so great that the sodium is discharged and taken into the mercury as an amalgam.
2. A voltage in excess of that which is normal, safe, or allowed for.
1921S. Q. Hayes Switching Equipment for Power Control v. 157 Relays are built to furnish protection on A.C. or D.C. circuits against overvoltage, no voltage, overload, no load, reverse load and reverse phase. 1963B. Fozard Instrumentation Nucl. Reactors v. 56 It may sometimes occur that a tube must be used with an insensitive scaling equipment, in which case a high overvoltage may be necessary to give satisfactory operation. |