Electronics Glossary – E
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| Term | Definition |
|---|---|
| E | Symbol used for voltage. Also written e. |
| E1 | The term for a digital facility used for transmitting data over a telephone network at 2.048 Mbps. The European equivalent of T1. |
| E3 | The highest transmission rate generally available in the European digital infrastructure (34 Mbps). |
| EAROM | Electrically alterable readonly memory. A reprogrammable ROM in which each cell can be individually erased by a special electrical process. |
| EBCDIC | Extended Binary-Coded Decimal Interchange Code. An 8-bit code used to represent 256 unique letters, numbers, and special characters. |
| ECCM | The defensive use of electronic warfare to counteract an opponent’s electronic countermeasures. |
| E-CGI | Enhanced Cell Global Identity |
| Echo Cancellation | Process by which a transmitter/receiver cancels out the transmitted signal as to “hear” the received signal better. |
| ECL | Emitter coupled logic – A bipolar logic family that works by diverting current from one path to another, rather than by switching transistors on and off. Characterized by very fast operating speeds and high power dissipation. Also called currentmode logic (CML). |
| ECM | The offensive use of electronic warfare. |
| eco | Abbreviation for electron-coupled oscillator. |
| Eddy Current Losses | Core losses associated with the electrical resistivity of the magnetic material and induced voltages within the material. Eddy currents are inversely proportional to material resistivity and proportional to the rate of change of flux density. Eddy current losses are present in both the magnetic core and windings of an inductor. Eddy currents in the winding, or conductor, contribute to two main types of losses: losses due to proximity effects and skin effects. As for the core losses, an electric field around the flux lines in the magnetic field is generated by alternating magnetic flux. This will result in eddy currents if the magnetic core material has electrical conductivity. Losses result from this phenomenon since the eddy currents flow in a plane that is perpendicular to the magnetic flux lines. Eddy current and hysteresis losses are the two major core loss factors. Eddy current loss becomes dominant in powder cores as the frequency increases. |
| EDFA | Erbium-doped fiber amplifier. |
| EDGE | Enhanced Data rates for Global Evolution |
| edge connector | A connector into which the edge of a printed circuit board is inserted. |
| edge pad | The portion of a printed circuit pattern (path, land) extending to the edge of a printed circuit board to provide a contacting surface for some type of connector. Also referred to as terminal area. |
| edge-mount connector | A connector that is mounted onto the edge of a printed circuit board. |
| Effective Area | For a magnetic core of a given geometry, the magnetic cross-sectional area that a hypothetical toroidal core of the same material properties would possess to be the magnetic equivalent to the given core. |
| Effective Length | For a magnetic core of a given geometry, the magnetic length that a hypothetical toroidal core of the same material properties would possess to be the magnetic equivalent to the given core. |
| Effective Permeability | For a magnetic circuit constructed with an air gap, or gaps, the permeability of a hypothetical homogeneous material that would provide the same reluctance, or net permeability. |
| Effective Volume | For a magnetic core of a given geometry, the magnetic volume that a hypothetical toroidal core of the same material properties would possess to be the magnetic equivalent to the given core. |
| Efficiency | Ratio of total output power to input power expressed as a percentage. Efficiency is normally measured at full rated output power and nominal input line conditions. |
| egg crating | Insulation walls between each cavity within the contact/wire entry face of the housing – usually appearing as rectangular cells. Normally allows the rear portion of the contact to be fully protected by housing material, thereby preventing shorts between adjacent contacts, and minimizing the danger of shock. Sometimes used to improve cross-talk characteristics, or to minimize the flexing of wires and/or contacts. |
| EGNOS | European Geostationary Navigation Overlay System |
| EID | Expanded Inside Diameter – The specified minimum (as supplied) internal diameter of tubing. |
| Elastic Memory | The ability of a crosslinked polymer to be deformed to some predetermined shape, hold that shape for a period, and then return to its original shape upon the application of heat. |
| elastomer | A material which at room temperature stretches under low stress to at least twice its length and snaps back to original length upon release of stress. |
| Electric Current | The movement of electric charge carriers in a medium. |
| Electric Field | Electric forces within a physical volume. |
| Electrical Length | Physical length expressed in terms of the wavelength of a signal for the medium in which the component or structure is situated. The units are degrees, radians or grads. |
| Electricity | A form of energy caused by the movement of electrons. |
| electroless plating | A chemical process by which nonconductive materials may be plated with a thin highly conductive film without using electric current. A thicker deposit of the desired metal may then be applied using standard electroplating methods. |
| Electromagnetic Field | Electric and magnetic forces that exist in a physical volume. |
| Electromagnetic Interference | EMI – An unwanted electrical energy in any form. EMI is often used interchangeably with ‘noise’ and ‘interference’. |
| Electromagnetic Radiation | The emanation of an electromagnetic field from a source through space. |
| Electromotive Force | The force that causes charge carriers to move from a location with high potential to a location with lower potential. |
| Electron | A subatomic particle that orbits the nucleus of an atom. Electrons have a negative charge. The charge of a single electron is -1.6 * 10-19 coulombs. When electrons escape from the immediate confines of an atom and move through a material, this motion constitutes electric current. |
| Electronic Counter-countermeasures | The defensive use of electronic warfare to counteract an opponent’s electronic countermeasures. |
| Electronic Countermeasures | The offensive use of electronic warfare. |
| Electronic Intelligence | The surreptitious gathering of information from an opponent or enemy through the use of electronic systems. |
| electronic interference | An electrical or electromagnetic disturbance that causes undesirable response in electronic equipment. Electrical interference refers specifically to interference caused by the operation of electrical apparatus that is not designed to radiate electromagnetic energy. |
| Electronic Warfare | The use of electronic signals and systems to disrupt the function of an opponent’s surveillance, defense or communications systems. |
| Electronics | The field of applied physics concerned with the behavior of electrons, especially when they move as current, in devices and materials. |
| electrostatic discharge | The sudden discharge of electrostatic charge that occurs when a charged conductor is grounded. |
| Electrostatic Discharge | ESD – Current produced by two objects having a static charge when they are brought close enough to produce an arc or discharge. |
| Electrostatic Sensitivity | The degree to which a component or device is susceptible to damage by electrostatic discharge. |
| Electrostatic Shield | Electrostatic shield that reduces coupling capacitance in transformers. The shield, which effectively reduces output common mode noise, is placed between the primary and secondary windings of a transformer. Also known as Faraday Shield. |
| electro-tinned | Electrolytic process of tinning wire using pure tin. |
| ELFEXT | Equal Level Far End Crosstalk. A measure of FEXT which accounts for the attenuation of the cabling system. |
| ELINT | The surreptitious gathering of information from an opponent or enemy through the use of electronic systems. |
| Elongation | The ultimate elongation, or elongation at rupture. Expressed as a percentage of original length. |
| embossing | A marker identification by means of thermal indentation leaving raised lettering on the sheath material of cable. |
| EMC | Electromagnetic compatibility. The ability of an electronic device to operate in its intended environment without its performance being affected by EMI and without generating EMI that will affect other equipment. |
| EMD | Equilibrium mode distribution. |
| emf | Electromotive force (voltage). |
| EMI | Electro-Magnetic Interference – An unwanted electrical energy in any form. EMI is often used interchangeably with ‘noise’ and ‘interference’. |
| EMI Filter | Filter placed at the input to an off-line converter that minimizes the effect of EMI on the converter and the associated system. |
| Emitter | The layer of a bipolar transistor through which all current flows and from which majority carriers are injected into the base of the transistor, where they are considered minority carriers. |
| Emitter Bias | The DC voltage or current that is applied to the emitter of a transistor to establish its operating point. |
| Emitter Current | The current that flows through the emitter of a transistor. |
| emitter-coupled logic | Abbreviated ECL. A bipolar logic family that works by diverting current from one path to another, rather than by switching transistors on and off. Characterized by very fast operating speeds and high power dissipation. Also called currentmode logic (CML). |
| emulator | An electronic circuit or computer program that performs functionally like another circuit or program; for example, a computer of one manufacturer emulating that of another manufacturer. |
| Enable | The act of asserting the enable signal to turn on the device. In the case of an EN low device, the EN signal must exceed the typical threshold voltage of 1.5V. |
| Enable High/Low | Some USB controller ships have enable logic that requires the power switch to be active low while others require the switch to be active high. This signal will be connected to the enable pin of the device selected. |
| Encapsulant | Description related to the way dual-wall tubing products and precoated molded parts melt and flow when heated, filling any void in the area being covered. Unlike an adhesive, an encapsulant does not form a mechanical bond to the substrate. |
| encapsulation | The process of embedding electrical components and conductors in a mechanically protective coating. |
| Enclosure | Case or container used to package a converter. Typically, converters are packaged in small plastic or metal. |
| encoder | A device which translates information from one form (code) to another (eg decimal to binary encoder). Normally, an encoder is used in the device sending the information. |
| End | The number of fibers or strands per carrier in braiding operations. |
| end of message | EOM – Usually a unique character in a data stream that indicates the end of a block of information data. |
| Energy Storage (.5LI2) | The amount of magnetic energy which can be stored in a given inductor in microjoules. It is the product of one half the inductance required in microhenries (µH) and the current (I) squared in amperes. |
| Energy Storage Inductors | Inductors used for energy storage, generally in power conversion rather than filtering or tuning. |
| engaging force | Force required to either engage or separate contacts – both in and out of the connector housing or insert. Values are generally established for maximum and minimum forces. Performance acceptance level vary per specification or customer requirements. Sometimes the forces are not only measured initially, but also after specified number of engagements and separations. |
| Enhanced Category 5 | Also called Category 5e.A performance classification for twisted pair cables, connectors and systems.Specified to 100 MHz.Suitable for voice and data applications up to 1000 Mbps. |
| Enterprise Network | A large typical corporate network under the auspices of one organization. |
| environment | The aggregate of all conditions (such as temperature, humidity, radiation, magnetic and electric fields, shock, and vibration) which externally influences the performance of an item. |
| environmentally sealed | A unit that is provided with gaskets, seals, grommets, potting, or other means to keep out moisture, dirt, air, or dust which might reduce or impair its performance. Does not include nonphysical environments such as RF and radiation. |
| EOM | End of Message. Usually a unique character in a data stream that indicates the end of a block of information data. |
| E-OTD | Enhanced Observed Time Difference |
| EPE | Estimated Position Error |
| Epitaxial | Of or pertaining to a layer of single crystal material grown on a crystalline substrate, with the same crystal orientation in both regions. |
| epitaxial layer | A thin precisely doped monocrystalline layer of silicone grown onto a heavily doped thick wafer, and into which the semiconductor junctions are diffused. In conventional integrated circuit processing, the thick wafer is “p” doped, and the epitaxial layer is “n” doped. |
| epoxy | A family of thermosetting resins used in the packaging of semiconductor devices. Epoxies form a chemical bond to many metal surfaces, and may be cast or molded. Epoxy should not be confused with silicone resins. |
| EPROM | Erasable, programmable read-only memory. A ROM in which the programmed data can be erased and the chip reprogrammed; it differs from the RAM in that the erasing and reprogramming requires special equipment not part of the system in which the EPROM is used. |
| EPSRC | Engineering & Physical Science Research Council |
| equilibrium mode distribution | The condition in an optical fiber in which all allowable modes propagate their characteristic amount of optical energy. |
| Equivalent Series Inductance (ESL) | Inductance in series with an “ideal” capacitor. Sources include leads, terminals, electrodes etc. |
| Equivalent Series Resistance (ESR) | Resistance in series with an “ideal” capacitor. Sources include lead resistance, terminal losses, etc. An important specification for high frequency applications. |
| Erbium-doped fiber amplifier | A type of fiber that amplifies 1550-nm optical signals when pumped with a 980- or 1480-nm light source. |
| Error Amplifier | Operational or different amplifier used in the control feedback loop of a converter. The amplifier produces an error voltage when the output (tapped off a voltage divider network) differs from a reference voltage. This error voltage is used to adjust the oepratioin of the PWM so as to correct the sensed output voltage. Sometimes called a Reference Amplifier. |
| ESCON | An IBM channel control system based on fiber optics. |
| ESD | Electrostaic discharge – Current produced by two objects having a static charge when they are brought close enough to produce an arc or discharge. |
| ESD | Electrostatic discharge is the sudden and momentary electric current that flows between two objects at different electrical potentials caused by direct contact or induced by an electrostatic field. |
| ETA | Estimated Time Of Arrival |
| etchant | A solution used to remove, by chemical reaction, the unwanted portion of a conductive material bonded to a base. |
| etched wire | A process applied to fluoroplastic wire in which the wire is passed through a sodium bath to create a rough surface to allow epoxy resin to bond the fluoroplastic. |
| etched wiring substrate | A printed conductive pattern formed by chemical, or chemical and electrolytic, removal of the unwanted portion of conductive material bonded to a base. |
| etching | The process of removing unwanted metallic substance bonded to a base – by chemical, or chemical and electrolytic, means. |
| ETE | Estimated Time Enroute |
| ETFE | Ethylenetetrafluoroethylene – A copolymer of ethylene and tetrafluoroethylene. This high temperature resin is well suited for wire insulation. It can withstand an unusual amount of physical abuse during and after installation, has very good electrical characteristics, good thermal and low temperature properties, and chemical inertness. |
| Ethernet | A baseband LAN specification invented by Xerox Corporation and developed jointly by Xerox, Intel, and Digital Equipment Corporation. Ethernet networks operate at 10 Mbps using CSMA/CD to run over coaxial cable. Ethernet has become a series of standards produced by IEEE referred to as IEEE 802.3. |
| ethylenepropylene rubber | These materials offer excellent resistance to ozone and weathering, good low temperature properties, good to excellent heat resistance and high temperature properties, and excellent electrical properties. Two types of the polymer are available – the copolymer based on ethylene and propylene only, and the terpolymer in which a small amount of unsaturation pendant to the chain is added. |
| Eutectic Solder | A solder consisting of two or more metals, all in the appropriate proportions to allow the lowest possible melting point for the given combination. |
| Evaporation | The physical change from the liquid to the gaseous state. |
| EW | Electronic Warfare – The use of electronic signals and systems to disrupt the function of an opponent’s surveillance, defense or communications systems. |
| exa | A prefix that indicates a factor of 1018, abbreviated as “E”. |
| Excess loss | In a fiber-optic coupler, the optical loss from that portion of light that does not emerge from the nominally operational ports of the device. |
| Excitation Current | The current required to overcome the losses in a core, which begins to produce magnetic energy (or flux) in an inductor. |
| excite | To initiate or develop a magnetic field in a motor or other electrical machine. |
| executive control program | A main system program designed to establish priorities, and to process and control other routines. |
| Expanded ID | Expanded Inside Diameter – The specified minimum (as supplied) internal diameter of tubing. |
| Expansion Ratio | An expression of how much larger the inside diameter of a tubing is before shrinking. Specifically, the relationship of the minimum (expanded) inside diameter of tubing to the maximum (recovered) inside diameter, expressed as a ratio. See also Shrink Ratio. |
| extender | A substance added to a plastic composition to reduce the amount of the primary resin required per unit volume. |
| external storage | That portion specially designed to receive and store information for use at a later time, external to . Also called storage. |
| extraction tool | A tool used for removing a contact from a connector. Most extraction tools will remove a contact in such a manner that the contact can be re-used, if desired. |
| Extrinsic loss | In a fiber interconnection, that portion of loss that is not intrinsic to the fiber but is related to imperfect joining, which may be caused by the connector or splice. |
| extrinsic properties | The properties of a semiconductor as modified by impurities or imperfectionswith in a crystal. |
| extrinsic semiconductor | A semiconductor whose electrical properties are dependent upon impurities added to the semiconductor crystal, in contrast to an intrinsic semiconductor whose properties are characteristic of an ideal pure crystal. |
| Extrusion | A process that conveys plastic insulation material, generally via a screw, through forming dies and subsequently cools the insulation material to form a predetermined shape. |
| eyelet | A short length of metal tubing used in the terminal holes of printed circuit boards to provide a through connection and a tight mechanical contact with the printed wiring prior to soldering. Eyelets are sometimes used in place of plated thru holes and should not be confused with “fillets” which serve only to hold the component in place prior to soldering, and promote solder wicking. |