→ bg2305z : 是108-2 04/22 00:57
感謝指正
※ 編輯: chun10396974 (223.136.224.202 臺灣), 04/22/2020 10:50:22
課程名稱︰電子學(二)
課程性質︰電機工程學系大二必修
課程教師︰林宗賢
開課學院：電機資訊學院
開課系所︰電機工程學系
考試日期（年月日）︰2020/4/21
考試時限（分鐘）：50分鐘
試題 :
1. A CS amplifier that can be represented by the equivalent circuit of Fig.1
has Cgs = 1pF, Cgd = 0.05pF, CL = 1pF, gm = 4mA/V, and R'sig = R'L = 20kΩ
(a) Find the midband gain AM. (10%)
(b) Find tje input capacitance Cin using the Miller approximation. (20%)
(c) Obtain the estimate of fH using open-circuit time constants. (20%)
┌─R'sig┬─Cgd───┬──┬──┐ +
+ │ + │ │ │ │
V'sig○ Vgs Cgs gmVgs↓ ◇ R'L CL Vo
- │ - │ │ │ │ -
≡ ≡ ≡ ≡ ≡
Fig.1 Generalized high-frequency equivalent circuit for the CS amplifier
2. Consider a feedback amplifier for which the open-loop gain A(s) is given by
10000
A(s)= ────────────────
(1 + s/10000) (1 + s/100000)^2
If the feedback factor β is independent of frequency,
(a) Find the frequency at which the phase shift is 180° . (25%)
(b) Find the critical value of β at which oscillation will commence. (25%)
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https://imgur.com/yEoiJJx
你們或許從肉身的枷鎖中解放了出來，但難道不是又進了另一個更為痛苦的牢籠嗎？
在人們造出的名為「社會」的牢籠中，被別人決定自身價值、被別人裁決的生活。我不想
為了在樂園生活而願意淪為一名奴隸。—丁格
———《樂園追放—Expelled from Paradise》
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