作者: alan3340 (alan3340) 2015-12-08 21:56:00
46.hfe=rπ/gm=50000,Rin=10k//10k//(2k+50k*100)=5kΩRi'=R/(1-A)=100k/101=990.1Ω,Rin=Ri'//10k=900.9Ω49題在想是不是要出負回授結果又出成下回授(台電常搞這鳥龍)正回授以正回授解;Vr2=11k/1k*5,Vth2=(-1k/10k)*10+Vr2=4.5V∵Vs>Vth2,∴Vo2=VDD=10VVr1(用節點算)=7.89V,Vth1=(-1k/10k)*10+Vr1=7.679V∵Vs<Vth1,∴Vo1=0Vopa1正回授沒有虛短路所以Vr1實在想不出來要如何簡單一點解,只好權當虛短路解以負回授解;Vo2=(-10/1)*6+(1+10/1)*5=0VV1-(節點解)=30/19V,Vo1=(-10/1)*6+(1+10/1)*30/19=0V