[理工] [電子]-Feedback Amplifier
The feedback amplifier in Fig.3 has I=1mA and V_gs =0.8V. The MOSFET has
Vt=0.6vand V_A=30V. For Rs =10k 歐姆 ,R1= 1M 歐姆 , and R2 =4.7M歐姆,find the
voltage gain Vo/Vs ,the input resistance Rin ,and the output resistance Rout.
附圖如連結
http://www.wretch.cc/album/show.php?i=u61i6m4&b=18&f=1483674689&p=8
我解題步驟如下
1.判定為 shunt-shunt
所以我馬上就把 電壓源轉成電流源 @@
2.畫出 β 網路
1
求得β值= - ------
4.7M
R_iβ=4.7M
R_oβ=4.7M
3.畫出無回授電路圖
求得 A = Vo/Is (為轉阻回授放大器) = -2974 k (V/A)
Ri' = 9.98k 歐姆
Ro' = 29.8k 歐姆
4.
A Vo
Af = -------- = ---- = -1821k
1 + Aβ Is
Vo/Vs = Af/Rs = -182.12 (V/V)
^^^^^^^^^^^^^
5.
Ri'
Rif = ------- 又Rs//Rin =Rif 求得 Rin=15.67k
1 + Aβ ^^^^^^^^^^^
Ro'
Rof = ------- = Rout =18.25 k 歐姆
1 + Aβ ^^^^^^^
可是算出來的答案好像怪怪的
有人跟我算出來的答案差不多嗎 @@?
解答 : Vo/Vs = -4.56 (V/V)
Rin = 1015.6k ohm
Rout = 0.55k ohm
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◆ From: 118.171.94.132
※ 編輯: u61i6m4 來自: 118.171.94.132 (01/26 16:40)
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所以要先把R1和Rs做串連 看成一個新的Rs??
那我猜我大概是錯在這步驟 @@
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※ 編輯: u61i6m4 來自: 114.47.150.115 (01/26 22:07)
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