78m05 引脚,78m05引脚

三极管yd78m05引脚接线图,及作用?
l78m05acdt
regulator fw78m05b-to251-252 spec-fw
mc78m05: 5.0 v, 500 ma positive linear voltage regulator
78m05稳压电路我用万用表进行检测输出的是0v怎么办