设P(A)=0.5,P(B)=0.4,P(A|)=0.6,求P(AB),P(A|AU)。
Hospital doctors don’t go out very often as their work__________ aU their time.
A.takes away
B.takes in
C.takes over
D.takes up
A.AU通道保护是恢复式的(返回式)
B.TU通道保护是非恢复式的(非返回式)
C.AU通道保护是非恢复式的(非返回式)
D.TU通道保护是恢复式的(返回式)
A.in au
B.at best
C.for all
D.by far
电路如图P2.7所示,晶体管的β=80,rbb=100Ω.分别计算RL=∞和RL=3kΩ时的Q点、Au、Ri和R0.