【单选题】电路如图所示。已知U2=20V,稳压管的 =9V,R=300Ω, =300Ω。若不慎将稳压管开路了,电路的输出电压 为 。
【单选题】There is no ____ in the bus and we have to wait for another.
【简答题】While we_1___(wait) for the bus, a girl_2___( run) up to us.
【简答题】稳压电源电路如图所示,(1) 该电路输出电压U0值为多少伏?(2) 若测得UC=12V,问U2值为多少?(3)若已知U2=20V,并测得UC=18V,分析电路发生了什么的故障?
【简答题】Rewrite the following passage, giving the sentences some variety in length and structure I got up a little later than usual on Sunday morning. I washed and had a quick breakfast. Then I started going ...
【简答题】Task 4Rewrite the following passage , giving thesentences some variety in length and structure: 1. I got up alittle later than usual on Sunday morning. I washed and had a quick breakfast. Then I start...