三極管的Pspice模型參數(shù)

第第#頁共9頁Figure2-Temperaturecontrolledresistor12OKU8OKU40KULLL」LLL」—ILIILIIL——^0U-40O4080□U(I1：-)TEMPFigure3-PSpiceplotofResistancevs.Temperature(current=1A)VariableQRLCnetworkInmostcircuitsthevalueofaresistorisfixedduringasimulation.WhilethevaluecanbemadetochangeforasetofsimulationsbyusingaParametricSweeptomovethroughafixedsequenceofvalues,avoltage-controlledresistorcanbemadetochangedynamicallyduringaSimulation.ThisisillustratedbythecircuitshowninFigure5,whichemploysavoltage-controlledresistor.Thiscircuitemploysanexternalreferencecomponentthatissensed.Theoutputimpedanceequalsthevalueofthecontrolvoltagetimesthereference.Here,wewilluseRref,a50ohmresistorasourreference.Asaresult,theoutputimpedanceisseenbythecircuitasafloatingresistorequaltothevalueofV(Control)timestheresistancevalueofRref.Inourcircuit,thecontrolvoltagevalueissteppedfrom0.5voltto2voltsin0.5voltsteps,therefore,theresistancebetweennodes3and0variesfrom25ohmsto100ohmsin25ohm-steps.

C1F：11G00G1IN+DU1IN-匚iL「GWLIJETRAN=PULSBQDV.1V.D.5ms.1us.lus.D.5ms.4ms)C1F：11G00G1IN+DU1IN-匚iL「GWLIJETRAN=PULSBQDV.1V.D.5ms.1us.lus.D.5ms.4ms)PARAMETERS:Rref=50iLimHControlX%lN+.%lN＜：L'i；RrerX.：：ontrolXi"“1uFAtransientanalysisofthiscircuitusinga0.5mswidepulsewillshowhowtheringingdiffersastheQisvaried.UsingProbe,wecanobservehowtheringingvariesastheresistancechangeSFigure6showstheinputpulseandthevoltageacrossthecapacitorC1.Comparingthefouroutputwaveforms,wecanseethemostpronouncedringingoccurswhentheresistorhasthelowestvalueandtheQisgreatest.Anysignalsourcecanbeusedtodrivethevoltage-controlledresistance.Ifwehadusedasinusoidalcontrolsourcei