题目内容
如图5所示为一个简单的报警器电路图,下列说法正确的是 ( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241408113714691.png)
A.Sl,S2都合上时报警器发声; |
B.Sl断开,S2合上时报警器发声; |
C.Sl,S2都断开时报警器发声; |
D.Sl闭合,S2断开时报警器发声。 |
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241408113714691.png)
D
当与门输出为高电压时报警器报警,当Sl闭合,S2断开时两个支路均输出高电压,所以与门输出为高电压,D对;
![](http://thumb2018.1010pic.com/images/loading.gif)
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