A.逆流二極管 B.空氣開(kāi)關(guān) C.充電電阻 D.充電保險(xiǎn)
A.5s B.15s C.10s D.20s
A.0.3~0.4V B.0.2~0.5v C.0.3~0.6V D.0.4~0.5V