Encyclopædia Britannica Australia -

Encyclopedias since 1768

0-9

electric switch ... electronic game

electric switch: device for opening and closing electrical circuits under normal load conditions, usually operated manually. There are many designs of switches; a common type-the toggle, or tumbler, switch-is widely used in home lighting and other applications. The so-called mercury, or "silent," ...
electrical and electronics engineering: the branch of engineering concerned with the practical applications of electricity in all its forms, including those of the field of electronics. Electronics engineering is that branch of electrical engineering concerned with the uses of the electromagnetic spectrum and with ...
Electrical and Electronics Engineers, Institute of: international organization of engineers and scientists in electrical engineering, electronics, and allied fields, formed in 1963 by merger of the American Institute of Electrical Engineers (founded 1884) and the Institute of Radio Engineers (founded 1912). It publishes the monthly Journal ...
electrical double layer: region of molecular dimension at the boundary of two substances across which an electrical field exists. The substances must each contain electrically charged particles, such as electrons, ions, or molecules with a separation of electrical charges (polar molecules). In the ...
electrical impedance: measure of the total opposition that a circuit or a part of a circuit presents to electric current. Impedance includes both resistance and reactance (qq.v.). The resistance component arises from collisions of the current-carrying charged particles with the internal structure ...
electrical shock: the perceptible and physical effect of an electrical current that enters the body. The shock may range from an unpleasant but harmless jolt of static electricity, received after one has walked over a thick carpet on a dry day, to ...
electricity: phenomenon associated with stationary or moving electric charges. Electric charge is a fundamental property of matter and is borne by elementary particles. In electricity the particle involved is the electron, which carries a charge designated, by convention, as negative. Thus, ...
electrocardiography: method of graphic tracing (electrocardiogram; ECG or EKG) of the electric current generated by the heart muscle during a heartbeat. The tracing is recorded with an electrocardiograph (actually a relatively simple string galvanometer), and it provides information on the condition ...
electroceramics: category of advanced ceramic materials that are employed in a wide variety of electric, optical, and magnetic applications. In contrast to traditional ceramic products such as brick and tile, which have been produced in various forms for thousands of years, ...
electrochemical reaction: any process either caused or accompanied by the passage of an electric current and involving in most cases the transfer of electrons between two substances-one a solid and the other a liquid.
electrochemistry: branch of chemistry concerned with the relation between electricity and chemical change. Many spontaneously occurring chemical reactions liberate electrical energy, and some of these reactions are used in batteries and fuel cells to produce electric power. Conversely, electric current can ...
electrocution: method of execution widely used in the United States, in which the condemned person is subjected to a heavy charge of electric current. The prisoner is made to sit in a wired chair, and electrodes are fastened to his head ...
electrode: electric conductor, usually metal, used as either of the two terminals of an electrically conducting medium; it conducts current into and out of the medium, which may be an electrolytic solution as in a storage battery, or a solid, gas, ...
electroencephalography: technique for recording and interpreting the electrical activity of the brain. The nerve cells of the brain generate electrical impulses that fluctuate rhythmically in distinct patterns. In 1929 Hans Berger of Germany developed an electroencephalograph, an instrument that measures and ...
electroforming: making duplicates by electroplating metal onto a mold of an object, then removing the mold. Intricate surface details are exactly reproduced by this process, which is used to make masters for pressing phonograph records. Electroforming is also used for reproducing ...
electrogasdynamics: study of the forces produced by the motion of electrically charged particles (ions) carried by an insulating gas flowing through an electric field. See also magnetohydrodynamic power generator.
electrojet: streaming movement of charged particles in the ionosphere. The term is limited by some to those flow patterns that contain a significant proportion of neutral gases, but highly concentrated, laterally limited, electric currents are also called electrojets. The latter circulate ...
electroless plating: nonelectrical plating of metals and plastics to achieve uniform coatings by a process of controlled autocatalytic (self-continuing) reduction. Discovered in 1944 by A. Brenner and G.E. Riddell, electroless plating involves the deposition of such metals as copper, nickel, silver, gold, ...
electroluminescence: production of light by the flow of electrons, as within certain crystals. Electroluminescence is one of the few instances in which a direct conversion of electric energy into visible light takes place without the generation of heat, such as occurs ...
electrolysis: process by which electric current is passed through a substance to effect a chemical change. The chemical change is one in which the substance loses or gains an electron (oxidation or reduction). The process is carried out in an electrolytic ...
electrolyte: in chemistry and physics, substance that conducts electric current as a result of a dissociation into positively and negatively charged particles called ions, which migrate toward and ordinarily are discharged at the negative and positive terminals (cathode and anode) of ...
electrolytic cell: any device in which electrical energy is converted to chemical energy, or vice versa. Such a cell typically consists of two metallic or electronic conductors (electrodes) held apart from each other and in contact with an electrolyte (q.v.), usually a ...
electromagnet: device consisting of a core of magnetic material surrounded by a coil through which an electric current is passed to magnetize the core. An electromagnet is used wherever controllable magnets are required, as in contrivances in which the magnetic flux ...
electromagnetic field: a property of space caused by the motion of an electric charge. A stationary charge will produce only an electric field in the surrounding space. If the charge is moving, a magnetic field is also produced. An electric field can ...
electromagnetic radiation: in terms of classical theory, the flow of energy at the universal speed of light through free space or through a material medium in the form of the electric and magnetic fields that make up electromagnetic waves such as radio ...
electromagnetism: science of charge and of the forces and fields associated with charge. Electricity and magnetism are two aspects of electromagnetism.
electromechanical transducer: any type of device that either converts an electrical signal into sound waves (as in a loudspeaker) or converts a sound wave into an electrical signal (as in the microphone). Many of the transducers used in everyday life operate in ...
electrometer: instrument designed to measure very small voltages and currents. The quadrant, Lindermann, Hoffman, and Wulf electrometers measure electrical potential between charged elements (e.g., plates or fine quartz fibres) within the housings of the electrometer. The sensitivity of these instruments is ...
electromotive force: energy per unit electric charge that is imparted by an energy source, such as an electric generator or a battery. Energy is converted from one form to another in the generator or battery as the device does work on the ...
electromotive series: listing of chemical species (atoms, molecules, and ions) in the order of their tendency to gain or lose electrons (be reduced or oxidized, respectively), expressed in volts and measured with reference to the hydrogen electrode, which is taken as a ...
electromyography: the process of graphically recording the electrical activity of muscle. Normal muscle is electrically silent when at rest, but when it is active, as during contraction or stimulation, an electrical current is generated, and the successive action potentials (impulses) can ...
electron: lightest stable subatomic particle known. It carries a negative charge, which is considered the basic unit of electric charge. The rest mass of the electron is 9.109 × 10⁻³¹ kg, which is only 11,840the mass of a proton. An electron ...
electron affinity: in chemistry, the amount of energy liberated when an electron is added to a neutral atom to form a negatively charged ion. The electron affinities of atoms are difficult to measure, hence values are available for only a few chemical ...
electron beam: stream of electrons (as from a betatron) generated by heat (thermionic emission), bombardment of charged atoms or particles (secondary electron emission), or strong electric fields (field emission). Electrons may be collimated by holes and slits, and, because they are electrically ...
electron capture: one of three processes of radioactive disintegration known as beta decay (q.v.).
electron charge: (symbol e), fundamental physical constant expressing the naturally occurring unit of electric charge, equal to 1.6021892 × 10⁻¹⁹ coulomb, or 4.80325 × 10⁻¹⁰ electrostatic unit (esu, or statcoulomb). In addition to the electron, all freely existing charged subatomic particles thus ...
electron diffraction: bending of a beam of electrons when passing near matter or through spacings in its submicroscopic structure that are comparable in size to the wavelength of an electron. According to the proposal (1924) of the French physicist Louis de Broglie, ...
electron gun: electrode structure that produces and may control, focus, and deflect a beam of electrons, as in a television picture tube (see ), where the beam produces a visual pattern on the tube's screen. The source of the electron beam is ...
electron microscope: microscope that attains extremely high resolution using an electron beam instead of a beam of light to illuminate the object of study. See microscope.
electron optics: branch of physics that is concerned with beams of electrons, their deflection and focusing by electric and magnetic fields, their interference when crossing each other, and their diffraction or bending when passing very near matter or through the spacings in ...
electron paramagnetic resonance: selective absorption of weak radio-frequency electromagnetic radiation (in the microwave region) by unpaired electrons in the atomic structure of certain materials that simultaneously are subjected to a constant, strong magnetic field. The unpaired electrons, because of their spin, behave like ...
electron scattering: random collisions of the charge carriers (electrons) with atoms in a crystalline solid (e.g., metal, semiconductor, or insulator) that decreases the mobility of the carriers. The deflection of a beam of electrons by a target also is called electron scattering. ...
electron spectroscopy: method of determining the energy with which electrons are bound in chemical species by measuring the kinetic energies of the electrons emitted upon bombardment of the species with X-ray or ultraviolet radiation. Details of the structure may be inferred from ...
electron synchrotron: type of synchrotron designed to accelerate electrons to high energies (see synchrotron).
electron tube: device usually consisting of a sealed glass or metal-ceramic enclosure that is used in electronic circuitry to control a flow of electrons. Among the common applications of vacuum tubes are amplification of a weak current, rectification of an alternating current ...
electron volt: unit of energy commonly used in atomic and nuclear physics, equal to the energy gained by an electron (a charged particle carrying unit electronic charge when the electrical potential at the electron increases by one volt). The electron volt equals ...
electronegativity: in chemistry, the ability of an atom to attract to itself an electron pair shared with another atom in a chemical bond.
electronic carillon: 20th-century musical instrument in which the acoustical tone source-metal tubes, rods, or bars struck by hammers-is picked up electromagnetically or electrostatically and converted into electrical vibrations that are highly amplified and fed into loudspeakers placed in a belfry or other ...
electronic configuration: the arrangement of electrons in energy levels around an atomic nucleus. According to the older shell atomic model, electrons occupy several levels from the first shell nearest the nucleus, K, through the seventh shell, Q, farthest from the nucleus. In ...
electronic eavesdropping: the act of electronically intercepting conversations without the knowledge or consent of at least one of the participants. Historically, the most common form of electronic eavesdropping has been wiretapping, which monitors telephonic and telegraphic communication. It is legally prohibited in ...
electronic game: any interactive game operated by computer circuitry. The machines, or "platforms," on which electronic games are played include general-purpose shared and personal computers, arcade consoles, video consoles connected to home television sets, and handheld game machines. The term video game ...