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如果將照明開關(guān)串接在零線上,雖然斷開時電燈也不亮,但燈頭的相線仍然是接通的,而人們以為燈不亮就會錯誤地認(rèn)為燈是處于斷電狀態(tài)。而實際上燈具上各點的對地電壓仍是220V的危險電壓。如果燈滅時人們觸及這些實際上帶電的部位.就會造成觸電事故。
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開關(guān)和保險絲 An electric switch is often on a wall near the door of a room. Two wires lead to the lamp in the room. The switch is fixed in one of them. The switch can cause a break in this wire, and then the light goes. The switch can also join the two parts of the wire again, then we get a light. Switch can control many different things. Small switches control lamps and radio sets because th