為什么通訊電源是-48的???
一直搞不明白,有誰明白,說來聽聽
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@feelbetter
我覺得第5貼說保護接地金屬不被腐蝕是不對的,接地金屬為正,其他負離子(可考慮HCl的氯離子)向他移動,結果與金屬結合發生反應.最好看完整個貼再說.
其實第5帖說的"腐蝕"是對的,不過理由不是氧化,是原子遷移,原子移走了,銅身變幼了,慢慢的斷了.抄一段 :
Subscriber-line interface cards (SLICs) provide the interface between the telephone-service provider and the telephone handset in your home. ....... Telephone-system voltages are traditionally negative to prevent electromigration from eroding the installed copper wiring.
Subscriber-line interface cards (SLICs) provide the interface between the telephone-service provider and the telephone handset in your home. ....... Telephone-system voltages are traditionally negative to prevent electromigration from eroding the installed copper wiring.
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@qaz33510
其實第5帖說的"腐蝕"是對的,不過理由不是氧化,是原子遷移,原子移走了,銅身變幼了,慢慢的斷了.抄一段:Subscriber-lineinterfacecards(SLICs)providetheinterfacebetweenthetelephone-serviceproviderandthetelephonehandsetinyourhome........Telephone-systemvoltagesaretraditionallynegativetopreventelectromigrationfromerodingtheinstalledcopperwiring.
把這句話翻譯過來,正是說第五貼不正確.
第五帖說:保護接地金屬不被腐蝕.
注意接地的是正極,才有-48伏.
那句話:通信系統是負電壓(不是接地的正極)為了阻止氧化.
第五帖說:保護接地金屬不被腐蝕.
注意接地的是正極,才有-48伏.
那句話:通信系統是負電壓(不是接地的正極)為了阻止氧化.
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