The Illustrated Dictionary of Electronics - Loscha

oxide-coated cathode • ozone monitor 509oxide-coated cathode See OXIDE-COATED EMIT-TER.oxide-coated emitter An electron-tube cathode orfilament coated with a material, such as thoriumoxide, for increased electron emission at lowemitter temperatures.oxide-coated filament See OXIDE-COATEDEMITTER.oxide film 1. The thin film of iron oxide that constitutesthe recording surface of a magnetic diskor tape. 2. The layer of copper oxide formed onthe copper plate of a copper-oxide rectifier.oxide-film capacitor An electrolytic capacitor, socalled because the dielectric is a thin oxide film.oxide rectifier A solid-state rectifier using a junctionbetween copper and copper oxide. Also calledCOPPER-OXIDE RECTIFIER.oximeter A photoelectric instrument for measuringthe oxygen content of the blood. It operates bypassing visible light through the earlobe, and analyzingthe color and intensity of the emergingbeam. Also called ANOXEMIA TOXIMETER.oxygen Symbol, O. Abbreviation, O 2 . A gaseous element.Atomic number, 8. Atomic weight, 15.999.Constitutes 21% of Earth’s atmosphere. It readilycombines with various elements to form compounds(see OXIDATION).oxygen analyzer An electronic gas analyzer designedespecially to measure oxygen content. Theoperation of this instrument is based on the paramagneticproperties of oxygen.oxygen recombination In nickel-cadmium (NICAD)cells and batteries, a process in which oxygen isgenerated in the vicinity of the positive electrode,and is reduced with water in the vicinity of thenegative electrode. This produces battery heating.oz 1. Abbreviation of OUNCE. 2. Abbreviation ofOZONE.oz-in Abbreviation of OUNCE-INCH.ozocerite An insulating mineral wax. Dielectricconstant, 2.2. Dielectric strength, 4 to 6 kV/mm.Also spelled OZOKERITE.ozone Symbol, O 3 . An allotropic form of oxygen. Itsformula indicates that each molecule has threeatoms. Produced by the action of ultraviolet rays(or electrical discharge) on oxygen, its characteristicodor (somewhat like weak chlorine) can oftenbe detected around sparking contacts or in theair after a thunderstorm.ozone layer In the earth’s atmosphere, a layer ofozone gas in the upper troposphere and lowerstratosphere. It is produced by ultravioletradiation from space, mainly from the sun. Theozone layer tends to block ultraviolet radiation,reducing the amount that reaches the surface ofthe earth.ozone monitor An instrument for measuring theconcentration of ozone in the atmosphere. Oneversion measures the extent to which ultravioletradiation is absorbed by a sample of air; thegreater the absorption, the higher the ozone concentrationin the sample.