(多选题)14: 星形联结电路可以分为: A: 三相三线 B: 三相四线 C: 四相三线 D: 四相四线 ...
(判断题)18: 电流型逆变电路直流侧串大电容,相当于电压源。 A: 错误 B: 正确 ...
(多选题)12: 额定电压可能是以下值: A: 断态重复峰值电压UDRM B: 反向重复峰值电压URRM C: 通态(峰值)电压 D: UDRM与URRM的平均值 ...
(判断题)16: 承受正向电压时,仅在门极有触发电流的情况下晶闸管才能开通。 A: 错误 B: 正确 ...
(单选题)10: PWM是()的简称。 A: 脉冲相位调制 B: 脉冲幅度调制 C: 脉冲频率调制 D: 脉冲宽度调制 ...
(单选题)4: 晶闸管延迟时间td的定义是,门极电流阶跃时刻开始,到阳极电流上升到稳态值的()的时间。 A: 5% B: 8% C: 10% D: 15% ...
(单选题)24: It’s usually quiet here _____ Sunday mornings. A: on B: in C: at D: the ...
(单选题)18: — Hello, I’m Harry Potter. — Hello, my name is Charles Green, but ______. A: call my Charles B: call me at Charles C: call me Charles D: call Charles me ...
(单选题)6: I do not intend to follow that, because we shall have an opportunity to do so on another ______. A: occasion B: situation C: condition D: environment ...
(单选题)19: "Do I have to meet you at the station?" "It's up to you. You______ if you don't want to." A: needn't B: mustn't C: shouldn't D: wouldn't ...