Electroencephalography (EEG) - The graphical recording of the electrical activity of the brain by means of electrodes attached to the scalp
Electroforming - The electrolytic deposition of metal on a conducting mould (usually graphite-coated wax) which can subsequently be removed by melting. The process is used, for example, for accurate reproduction or the manufacture of precision tubing.
Electrokinetic Phenomena - Denotes the interrelated series of effects having to do with the electrical behaviour of solid-liquid interfaces. The term embraces colloid phenomena (solid phase mobile), on the one hand and capillary phenomena (liquid phase mobile), on the other.
Electrokinetic Potential: Zeta Potential - At a solid-liquid interface in a colloid system: the potential existing across the diffuse portion of the electrical double layer.
Electroless Deposition - Electro-deposition which is achieved in the absence of an electric current the necessary ions for the formation of a metallic film being supplied, for an appropriate metal, by a suitable choice of electrolyte.
Electrolysis - In general, signifies the passage of an electric current through a liquid containing charged particles or ions. The current flows in both directions and is thus fundamentally different from that in a metallic conductor.
Electrolyte - (1) A substance whose solution conducts electrictiy by the movement of positive and negative ions. (2) The solution itself Electrolytic Polishing. The process of producing a smooth lustrous surface on a metal by making the metal the anode in an electrolytic solution. The protuberance are dissolved away preferentially.
Electrolytic Reduction - The extraction of metals from solution or from fused salts by electrolysis, usually for industrial purposes.
Electrolytic Refining - The removal of impurities from metallic material by electrolysis:
Electrolytic Tank - A shallow tank of electrolyte used for solving various problems for which the tank may be made to give an electrical analogy. It is of constant depth and of geometrical shape appropriate to the problem being investigated.
Electromagnet - A magnet whose field is produced by an electric current, and which is, to a large extent, demagnetized when the current is cut off.
Electromagnetic Field - A field representing the joint interplay of electric and magnetic forces.
Electromagnetic Induction - The setting up of an electric field by reason of the variation in magnetic flux density with time. Any current so induced is in such a direction as to oppose the change in magnetic flux.
Electromagnetic Mass - Of a charged particle: the mass arising from the motion of the particle.
Electrical Protective Gear Or Cutout - A relay or group of relays and accessories intended, in case of fault or abnormal conditions, either to isolate a zone of an electrical installation or to actuate a warning signal
Electric Field Strength - The force experienced by a stationary unit positivec charge placed in an electromagnetic field - In MKSA and SI units it is expressed in newtons per coulomb - The electric field strength is sometimes called electric intensity
Electric Flux - At a surface in an electrostatic field: the quantity of electricity displaced across the surface and normal to it - The unit is the Coulomb - Also known is the flux of displacement
Electric Flux Density - The electric flux per unit area . It is the same as the displacement. It is expressed in Coulombs per unit area (cm² or m²)
Electric Intensity - See: Electric field strength
Electricity - The manifestation of the existence of electric charge, ultimately derived from the ionization of atoms - According as it is concerned with stationary charges or moving charges it is known as static or current electricity
Electric Motor - A machine which converts electrical energy into mechanical energy
Electroanalysis - Analysis by any technique which involves the measurement of an electrical property (e - g - current or potential) of an electrolytic cell -
Electrocapillarity - The change in the surface tension at an interface between two phases when an electrical field is imposed - The term refers especially to the change in a capillary tube when a voltage is applied across them
Electrocardiography (ECG) - The graphical recording of the electrical activity of the heart muscle by means of electrodes attached to the wrists and one ankle
Electromagnetism. Denotes all those phenomena concerned with the interaction of electric and magnetic fields.
Electromerism: Electromeric Effect. The change in the electronic, configuration of a molecule as a result of conjugation.
Electrometer. An instrument for detecting, or measuring potential
difference or electric charge.
Electrometer, Capillary: Electrometer, Lippman. An electrometer in which small changes in potential difference are measured from the changes in level, in a Capillary tube, of the surface of separation between a mercury surface and an electrolyte.
Electrometer, Compton. A type of quadrant electrometer. having a controlled variable sensitivity.
Electrometer, Quadrant. The most commonly used. type of electrometer. It consists of a shallow cylindrical metal box cut into four quadrants, inside which a metal vane is suspended by a, vertical wire or conducting fibre.
Electrometer, Valve (or Tube). An electrometer, employing a triode valve, which operates by the d.c. amplification and measurement of an ionization current.
Electromotive Force (E.M.F.) The electrical force produced by the conversion of some form of energy into electrical energy. The conversion processes which can generate an e.m.f include the conversion of mechanical energy (as in a dynamo), of heat energy (as in a thermocouple), of magnetic energy (as in an inductance), and of chemical energy (as in an battery). Electromotive force is to
be distinguished from potential difference, which is a general term signifying a difference in potential energy, or of voltage, which exists between two points in a circuit or between two electrically charged bodies.
Electromyography (EMG). The graphical recording of the electric currents and action potentials generated in a muscle during its contraction, by means of concentric needle electrodes inserted into the muscle.
Electron. A stable elementary particle having an electric charge of ±1.602 x 10-19C and a rest mass of 9:109 x 10-31 kg. When used
without specification the term means the negatively charged electron (also called a negatron of negaton). Its antiparticle is the positively charged electron (positron or position).
Electron Attachment - The capture of an electron by an atom or molecule to form a negative ill.
Electron-beam Machining - The use of electron beams in machining operations. The equipment is similar to that used in electron-beam melting, and is used to carry out such operations as the drilling of holes, the cutting of slots and profiles, and milling in general. The technique is applicable to ceramics as well as to metals.
Electron-beam Melting - The application of electron beams on the industrial scale to such operations as the refining, casting and welding of refractory metals, e.g. tungsten, molybdenum, and. zirconium.
Electron-beam Tube - An electron tube, the performance of which depends on the formation and control of one or more electron beams.
Electron Capture - (1) Electron attachment. (2) The capture of an orbital electron (usually a K-electron) by an atomic nucleus . The vacancy is filled by an electron from an outer shell with the emission of fluorescence X-rays or Auger electrons.
Electron Cloud - Refers to an interpretation of the Schrödinger wave function, Ψ,for an atomic electron whereby it is supposed that the electron is spread out in the form of a cloud, the density of which at a given point at a given time is proportional to Ψ 2 at that point. The function Ψ 2 is often called the probability density function of the electron cloud, See also:Schrödinger equation.