.图示电路中，电压源US=（    ）。

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69349' and id < 4489456 and id<>'4489456' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69349' and id > 4489456 and id<>'4489456' order by id asc limit 5