3带载R,=3kC2 Ⅰb1 Ⅰb27be 时 R B R rbi rb Re R R Re R r.=Rb/lre +(1+(re2b/ru B(R11R,) A1=A1·A2=-1765 17.8 Irhe +(l+brelb R -13.58 r+r 1+B)(R2∥R) =0.992 2 +(1+B)(R2∥R) 135.8mRL = 3k 17.8 [ (1 ) ] ( // ) //[ (1 )( // )] 1 ' 1 1 2 2 ' 2 2 = − + + = − = + + • • b e e b b c u b b e e L r R I I R R A R R r R R i i    s s U R • Rb11 Rb12 I b1 • rbe Re1 I b1 •  Rc1 Rb2 I b2 • rbe I b2 •  Re 2 RL U o • + _ + _   ' i 2 R 0.992 (1 )( // ) (1 )( // ) 2 2 2 = + + + = b e e L e L u r R R R R A   13.58 1 2 17.65 = − + = = • = − s i i u s u u u u R R R A A A A A Uo =Us • Au s = −135.8mV • • 3)带载 时