江苏春晨电缆有限公司生产YCB扁电缆,一种简易测量导线断芯位置的电路Asimplecircuitformeasuringbrokencorepositionofwire2015.12.1414:23评论：22015.12.1414:23comments:2对于内部断芯的绝缘导线、电缆线往往废弃不用，这是十分可惜的，假如能确定断芯位置，就可进行修复。Itisapitythattheinsulatedwiresandcableswithinternalbrokencoresareoftendiscarded.Ifthelocationofthebrokencorecanbedetermined,itcanberepaired.如下图所示电路是用NMOS场效应管组成一种测电笔电路，YCB扁电缆它能够方便地测出导线的断芯位置。测量时，被测导线一端接220V交流电源的相线，另一端悬空，合上控制开关SA，然后将感应测电笔的探头靠近被测导线，并沿导线移动，由于NMOS管的输入阻抗很高，放大倍数很大，所以只要栅极感应到微弱的电压信号，就能引起漏极电流的显著变化，漏极电流再通过三极管放大，足以使发光二极管发光。如果自上而下检查到某一位置时，发光二极管突然熄灭，则所处导线位置即为断芯处。Asshowninthefigurebelow,thecircuitiscomposedofNMOSfieldeffecttransistor,whichcaneasilymeasurethebrokencorepositionofthewire.Whenmeasuring,oneendofthemeasuredwireisconnectedtothephaselineofthe220VACpowersupply,andtheotherendissuspended.ClosethecontrolswitchSA,andthenmovetheprobeoftheinductivemeasuringpenclosetothemeasuredwireandalongthewire.BecausetheinputimpedanceoftheNMOStubeisveryhighandtheamplificationfactorisverylarge,aslongasthegridsensesaweakvoltagesignal,thedraincurrentwillchangesignificantly,andthedraincurrentwillpassthroughagainTriodeamplification,enoughtomakelight-emittingdiodes.IftheLEDsuddenlygoesoutwhenacertainpositionisdetectedfromtoptobottom,thepositionofthewireisthebrokencore.需要注意，检查时导线或电缆的绝缘层必须完好无损，否则容易触电。Itshouldbenotedthattheinsulationlayerofwireorcablemustbeintactduringinspection,otherwiseitiseasytogetelectricshock.)