【简答题】
A、如图所示为电桥电路,已知R1=1Ω、R2=2Ω、R3=2Ω、R4=4Ω、R5=5Ω,试求等效电阻Rab。r /> rc="https://img.ppkao.com/2018-05/tangxueping/2018051015543465216.jpg" />
A、电路如图P2.7所示,晶体管的β=60,rbb=100Ω。r /> rc="https://img.ppkao.com/2018-09/yuanhao/2018091014153362573.jpg" />