图示电路中，电压源=（）。 

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SQL Error: select id,body,options from ***_enewstiku where sourceid='32669' and id < 2598559 and id<>'2598559' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='32669' and id > 2598559 and id<>'2598559' order by id asc limit 5