某单相半波整流电路，若变压器次级电压U2=100V，则负载两端电压_爱下问搜题

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问题单项选择题

某单相半波整流电路，若变压器次级电压U2=100V，则负载两端电压及二极管承受的反向电压分别是（）。

A.45V和141V

B.90V和141V

C.90V和282V

D.45V和282V

答案

参考答案：A

选择题

— Where is Zhang Ming?

— Oh, don't you know he _____ to Beijing to see his parents and he'll be back tomorrow.[ ]

A. has gone

B. has been

C. had gone

问答题简答题

轴承的润滑油膜是怎样形成的？