The Illustrated Dictionary of Electronics - Loscha

2 abhenry • absolute errorand is the inductance across which a currentthat changes at the rate of 1 abampere per secondinduces a potential of 1 abvolt.ABL Abbreviation of Automated Biology Laboratory(NASA).abmho The obsolete unit of conductance and ofconductivity in the cgs electromagnetic system.Replaced with ABSIEMENS.abnormal dissipation Power dissipation higher orlower than the customary level, usually an overload.abnormal oscillation 1. Oscillation where none isdesired or expected, as in an amplifier. 2. Oscillationat two or more frequencies simultaneouslywhen single-frequency operation is expected.3. Oscillation at an incorrect frequency. 4. Parasiticoscillation.abnormal propagation 1. The chance shifting ofthe normal path of a radio wave, as by displacementsin the ionosphere, so that reception is degraded.2. Unintentional radiation of energy fromsome point other than the transmitting antenna.3. Propagation over a path or in a direction notexpected.abnormal reflections Sharp, intense reflections atfrequencies higher than the critical frequency ofthe ionosphere’s ionized layer.abnormal termination The shutdown of a runningcomputer program or other process. Caused bythe detection of an error by the associated hardwarethat indicates that some ongoing series ofactions cannot be executed correctly.abnormal triggering The false triggering or switchingof a circuit or device, such as a flip-flop, bysome undesirable source instead of the true triggersignal. Electrical noise pulses often cause abnormaltriggering.abohm The unit of resistance and of resistivity inthe cgs electromagnetic system. One abohmequals 10 –9 ohms and is the resistance acrosswhich a steady current of 1 abampere produces apotential difference of 1 abvolt.abort To deliberately terminate an operation, experiment,process, or project before it has run itsnormal course.AB power pack 1. A portable dry-cell or wet-cellarray containing both A and B batteries in onepackage. 2. An ac-operated unit in one packagefor supplying A and B voltages to equipment normallyoperated from batteries.abrasion machine An instrument for determiningthe abrasive resistance of a wire or cable.abrasion resistance A measure of the ability of awire or wire covering to resist mechanical damage.ABS A basic programming abbreviation for the absolutevalue (of a number, variable, or expression).abscissa 1. The independent variable in a function.2. The axis (usually horizontal) on the graph of afunction that indicates the independent variable.absence-of-ground searching selector A rotaryswitch that searches for an ungrounded contactin a dial telephone system.absiemens The unit of conductance or conductivityin the cgs electromagnetic system. Oneabsiemens equals 10 9 siemens and is theconductance through which a potential of 1 abvoltforces a current of 1 abampere.absolute 1. A temperature scale in which zero representsthe complete absence of heat. Units of measureare same as units on Celsius and Fahrenheitscales. See ABSOLUTE SCALE. 2. Independent ofany arbitrarily assigned units of measure or value.absolute accuracy The full-scale accuracy of a meterwith respect to a primary (absolute) standard.absolute address In a digital computer program,the location of a word in memory, as opposed tolocation of the word in the program.absolute code A computer code in which the exactaddress is given for storing or locating the referenceoperand.absolute coding In computer practice, coding thatuses absolute addresses.absolute constant A mathematical constant thathas the same value wherever it is used.absolute delay The time elapsing between thetransmission of two synchronized signals fromthe same station or from different stations, as inradio, radar, or loran. By extension, the time intervalbetween two such signals from any source,as from a generator.absolute digital position transducer A digital positiontransducer whose output signal indicatesabsolute position. (See ENCODER.)absolute efficiency The ratio X x /X s , where X x isthe output of a given device, and X s is the outputof an ideal device of the same kind under thesame operating conditions.absolute encoder system A system that permitsthe encoding of any function (linear, nonlinear,continuous, step, and so on) and supplies a nonambiguousoutput.absolute error The difference indicated by the approximatevalue of a quantity minus the actual