例2 ：=100，rbb=100，静态时vo=0V (1)计算静态电流 (2)计算差模放大倍数,例3：电路如图，静态时，Vo=0。求R=？,解：(1)静态分析：,IC3=IC4=2mA,VR5=2 IC4 R5=7.2V,VR3=VR4= VR5+VBE3 =7.9V,ID1=ID2=0.79mA,VR8= VR9 = 2 ID2 R8=5.7V,VR=12-0.7- VR8 =5.6V,IR9= VR8 / R9 =1.1mA,R= VR / IR9 =5.1K,设=150，gm=3mA/V，rbe3=rbe4=2.16k,输入输出同相,
