6.單相電源60赫茲在三相十二脈衝下,1個脈衝(pulse)的時間約為多少毫秒(ms)?
(A)8
(B)3
(C)1.4
(D)0.7
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統計: A(204), B(251), C(1454), D(302), E(0) #1529604
統計: A(204), B(251), C(1454), D(302), E(0) #1529604