某单相桥式整流电路,交流输入电压为220V时,试计算整流输出电压值?
参考答案:
根据单相桥整流电路特性可知:V=0.9u2
V=0.9×220=198V
整流输出电压值198V
(2013·河北普通高中高三质量监测)Lucy has changed a lot since she got her new job. Recently she ________ her work quite well.
A.has been doing
B.has done
C.did
D.had done
某工作最早开始时间5,最迟开始时间,持续时间6,其紧后工作最早结束时间16,持续时间4,其自由时差为( )。
A.1B.2C.3D.4