A.適當(dāng)減小比例帶 B.適當(dāng)增加比例帶 C.無(wú)須改變比例帶
A.AC220—500V B.AC36—380V C.AC或DC55—500V
A.最下 B.最上 C.與平衡錘最上時(shí)不一定完全對(duì)應(yīng)