A.7805 B.7915 C.7812 D.7912
A.主磁極數(shù) B.主磁極對數(shù) C.兩條
A.低位由0變1時(shí) B.上一級由1變0時(shí) C.下一級由1變0時(shí) D.無規(guī)律