【文章內(nèi)容簡介】 etween the upper and lower frequencies of the half power points of the response relative to the reference frequency.*bandwidthThe difference between the two dominant critical frequencies of an amplifier. It is also equal to the upper critical frequency when there is no lower critical frequency.*bandwidthThe data a cable can carry measured in bits per second (bps).*barUnit of pressure equivalent to 105pa.*barometerInstrument for measuring atmospheric pressure.*barrierA part providing a defined degree of protection against contact with live parts from any usual direction of access.*baseThe part of a transistor which separates the emitter from the collector. The middle part of the transistor. permits electrons from emitter to pass through to the collector.*baseThe reference quantity in a perunit or percentage calculation.*baseline forecastA prediction of future energy needs which does not take into account the likely effects of new conservation programs that have not yet been started.*base loadThe minimum load experienced by an electric utility system over a given period of time, which must be supplied at all times.*base load capacityCapacity of generating equipment operated to serve loads 24hours per day.*base load plantA power plant built to operate aroundtheclock. Such plants tend to have low operating costs and high capital costs and are best utilized by running continuously. Coal fired and nuclear fuelled plants are typical base load plants.*basic insulationInsulation applied to live parts to provide basic protection against electric shock and other hazards, which do not necessarily include insulation used exclusively for functional purposes.*basic insulation level *BILIt defines the insulation level of power system equipment. It is a statement of the impulse (lightning or switching as appropriate) withstand voltage and the short duration power frequency withstand voltage.*batteryA number of primary or secondary cells arranged in series or parallel. A device for turning chemical energy into electrical energy.*battery backupA battery or a set of batteries in a UPS system. Its purpose is to provide an alternate source of power if the main source is interrupted.*battery chargerA device or a system which provides the electrical power needed to keep the battery backup fully charged.*BCD *Binary coded decimal. A digital code based on 0 and 1.*beckmann thermometerSensitive thermometer for measuring small differences or changes in temperature.*belTen decibels. (see decibel)*bewley lattice diagramThis is a convenient diagram devised by Bewley, which shows at a glance the position and direction of motion of every incident, reflected, and transmitted surge on the system at every instant of time. The diagram overes the difficulty of otherwise keeping track of the multiplicity of successive reflections at the various junctions.*bhp, *BHP[see brake horse power].*BIL[see basic insulation level]*bilateral contractA direct contract between the power producer and user or broker outside of a centralized power pool.*billionA thousand million or 109(US). Also a million million (British)*bimetallic stripA strip posed of two different metals welded together in such a way that a rise of temperature will cause it to deform as a result of the unequal expansion. It is used in switches for control of temperature.*binary cellAn element in a puter which can store information by virtue of its ability to remain stable in one of two possible states.*binary coded decimal[see BCD]*binary notationA system of numbers which has only two different integer values 0 and 1.*biomassAny plantderived organic matter available on a renewable basis, including dedicated energy crops and trees, agricultural food and feed crops, agricultural crop wastes and residues, wood wastes and residues, aquatic plants, animal wastes, municipal wastes, and other waste materials.*bipolar transistorA transistor where both free electrons and holes are necessary for normal operation.*bisectionDivision into two equal parts.*bitThe unit of information in information theory. The amount of information required to specify one of two alternatives 0 and 1.*bitumenA term covering numerous tarry mixtures of hydrocarbons.*black bodyThermal radiator that absorbs pletely all incident radiation, whatever the wavelength, the direction of incidence or the polarization.*blackoutA total loss of the mercial electrical power lasting for more than one cycle. Blackouts can result from any of a number of problems, ranging from Acts of God (high winds, storms, lightning, falling trees, floods, etc.) to situations such as cables being cut during excavation, equipment failures at the utility, vandalism, corrosion, etc. Used synonymously with Outage.*blackoutA power loss affecting many electricity consumers over a large geographical area for a significant period of time.*blankingprocess of making the trace, or parts of a trace, invisible.*bleachingRemoving the colour from coloured materials by chemical transformation.*board of trade unit or *BOT unit.Unit of electrical energy (British) supplied to the consumer. Equal to 1 kWh. Energy obtained when a power of 1 kW of power is maintained for 1 hour.*bode plotSemilog plots of the magnitude (in decibel) and phase angle of a transfer function (or performance) against frequency.*boilingThe state of a liquid at its boiling point when the maximum vapour pressure of the liquid is equal to the external pressure to which the liquid is subject, and the liquid is freely converted into vapour.*boiling pointThe temperature at which the maximum vapour pressure of the liquid is equal to the external pressure. The temperature at which the liquid boils freely under that pressure.*boiling water reactor or *BWRA nuclear reactor in which water is used as coolant and moderator. Steam is thus produced in t