Subjecttopreconditi***.Weknowthatanysubstanceisrelativelyinsulated,andwhenthevoltageatbothendsofthematerialincreasestoacertainextent,thematerialcanconductelectricity.Wecallthisvoltageabreakdownvoltage.Capacitanceisnoexception.Whenthecapacitorisbroken,itisnotaninsulator.Inmiddleschool,however,suchvoltagesareinvisibleincircuits,sotheyworkbelowbreakdownvoltagesandcanbetreatedasinsulators.)