Phenol to Photomulliplier

Phenol-furfural resins to Photo-composing

Phenol-furfural resins. (Chem. Plast.) Made principally from oat hulls and coal. Used in pressure molding, positive, 'flash, transfer and injection molding, and lami­nating. Have wide range of appli­cation for electrical articles, cabi­nets, etc. Desirable from stand­point of superior moldability, permanence of dimensions dur­ing molding, high heat resistance, and stability of color.

Phenolic resins molding type. (Chern. Plast.) One of the oldest and most important family of plastics because of its low cost and combination of useful prop­ erties, outstanding of which are. its resistance to heat and most corrosive agents. It is a noncon­ductor of electricity, and from the beginning and now, electrical plugs, sockets, connectors, handles, and enclosures are made oif it, together with a host of other familiar housings and appliance parts. Phenolics result from a controlled reaction between phe­nol and formaldehyde, (See Plas­tics.)

Phenoplast. (Chem. Plast.) A gen­eral term for phenol-aldehyde resins. synonymous with popular term "phenolics."

Phillips machine screw. A metal or W90d holding screw made in a variety of head forms and having a four-point star-shaped recess in the head which requires a special tool for setting.
Phone. A speech sound.
Phonetics. The science or study of speech sounds and their produc­tion, transmission, and reception, and their analyses, classification and transcription.

Phono. Sound. Phonograph. Any sound producing machine .using records.
Phonometer. An instrument for mea­suring the intensity of a sound.

Phosphor. Any of a number of sub­stances that exhibit luminescence when struck by light of certain wavelengths.

Phosphor bronze. (Metal.) An al­loy composed of copper and tin to which a little phosphorus is added. It is largely used as a bearing metal.

Phosphorescence. The property of. being luminous at temperatures below incandescence, as from slow oxidation in the case of phosphorus or after exposure to light or other radiation.

Phosphorus. (Chem.) A light yel­low, waxlike solid; specific grav­ity 1.83; melting point 44.4 deg. C. It is marketed in the form of sticks which, being highly inflam­mable, must be kept under water.

Photocathode. A cathode, typically of a cesium or sodium compound that emits electrons when acti­vated by light or other radiation. Photocell. Phototube:

Photo-composing. (Print.) Type­ seting by means of photographi­ Photoconductive to Photomulliplier cally activated tape.
Photoconductive. Of pertaining to,or exhiniting, photoconductivity.

Photoconductivity. The increase of the electric conductivity of a sub­stance, often non-metallic, caused by the absorption of electromag­netic radiation.
Photocurrent. An electric current produced by a photo.electric effect.

Photolectric. Pertaining to the elec­tronic or other electric effects pro­duced by light.

Photoelectric cell. A device incorporated in an electric circuit to make the resistance or electro­motive force in part of the circuit variable in accordance with varia­tions in the intensity of light or similar radiation falling upon it, thus making operations controlled by the circuit dependent on varia­tions in illumination, a beam .of radiation or the like. Photoelectric current. Photo current.

Photoelectric effect. The pheno­menon . in which the absorption of electromagnetic radiation, as light, of sufficiently high fre­quency by a surface, usually metallic, induces, the emission of electrons from the surface.

Photoelectricity. Electricity induced by electromagnetic radiation, as the photoconductivity and pho­toionization.

Photo-en-graving. (Print.) Any engraving process accomplished by means of photography.

Photography. (Chern.) The process. of fixing an image of an object on a sensitized plate, film, or paper, by exposure to light, after which it is made permanent by treat­ment with certain chemicals.

Photogravure. (Print.) An intaglio plate for printing, in which there are no sharp lines but very small depressions; the high parts show white and the depressions pro­ duce . shadows.

Photometer. (Phys.) An instrument for measuring the interisity of light or for comparing the relative intensity of different lights.

Photo-micrograph. (Metal.) A pic­ture taken by a combination mi­croscope and camera for the pur­pose of studying specimens. The usual magnification is 100 to 500 times for metallic sections.

Photomultiplier. An extremely sen­sitive detector of light and of other radiation; consisting of a tube in which the electrons released by radiation striking a photocathode are accelerated to successive dy-nodes that release several electrons for each incident. . electron, greatly amplifying the signal produced by the invident radiation.