题目内容
一自耦调压变压器(可看做理想变压器)的电路如图甲所示,移动滑动触头P可改变副线圈匝数.已知变压器线圈总匝数为1900匝;原线圈为1100匝,接在如图乙所示的交流电源上,电压表为理想电表.则
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250012190338633.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250012190338633.png)
A.交流电源电压瞬时值的表达式为![]() |
B.P向上移动时,电压表的最大示数为380V |
C.P向下移动时,原、副线圈的电流之比减小 |
D.P向下移动时,变压器的输入功率变大 |
BC
试题分析:交流电源电压的最大值是
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001219064486.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001219080882.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001219096653.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250012191111300.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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