已知电路如图所示，开关闭合后的时间常数等于（）。 

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku where sourceid='32672' and id < 2598948 and id<>'2598948' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='32672' and id > 2598948 and id<>'2598948' order by id asc limit 5