Metal detector

《Metal detector》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、MetaldetectorFromWikipedia,thefreeencyclopediaJumpto:navigation,searchThisarticleneedsadditionalcitationsforverification.Pleasehelpimprovethisarticlebyaddingreliablereferences.Unsourcedmaterialmaybechallengedandremoved.(March2008)AU.S.Armysoldierusesametal

2、detectortosearchforweaponsandammunitioninIraqAmetaldetectorisadevicewhichrespondstometalthatmaynotbereadilyapparent.Thesimplestformofametaldetectorconsistsofanoscillatorproducinganalternatingcurrentthatpassesthroughacoilproducinganalternatingmagneticfield.

3、Ifapieceofelectricallyconductivemetalisclosetothecoil,eddycurrentswillbeinducedinthemetal,andthisproducesanalternatingmagneticfieldofitsown.Ifanothercoilisusedtomeasurethemagneticfield(actingasamagnetometer),thechangeinthemagneticfieldduetothemetallicobjec

4、tcanbedetected.Thefirstindustrialmetaldetectorsweredevelopedinthe1960sandwereusedextensivelyforminingandotherindustrialapplications.Usesincludede-mining(thedetectionoflandmines),thedetectionofweaponssuchasknivesandguns,especiallyinairportsecurity,geophysic

5、alprospecting,archaeologyandtreasurehunting.Metaldetectorsarealsousedtodetectforeignbodiesinfood,andintheconstructionindustrytodetectsteelreinforcingbarsinconcreteandpipesandwiresburiedinwallsandfloors.Contents[hide]·1Historyanddevelopmento1.1Moderndevelop

6、mentso1.2Furtherrefinementso1.3Discriminatorso1.4Newcoildesignso1.5Pulseinduction·2Useso2.1Archaeologyo2.2Asahobbyo2.3Securityscreeningo2.4Industrialmetaldetectors·3Seealso·4Notes·5References·6Externallinks[edit]HistoryanddevelopmentTowardtheendofthe19thce

7、ntury,manyscientistsandengineersusedtheirgrowingknowledgeofelectricaltheoryinanattempttodeviseamachinewhichwouldpinpointmetal.Theuseofsuchadevicetofindore-bearingrockswouldgiveahugeadvantagetoanyminerwhoemployedit.TheGermanphysicistHeinrichWilhelmDoveinven

8、tedtheinductionbalancesystem,whichwasincorporatedintometaldetectorsahundredyearslater.Earlymachineswerecrude,usedalotofbatterypower,andworkedonlytoaverylimiteddegree.AlexanderGrahamBellusedsuchadevicetoattemp