[理工] [電子學] 頻率響應

看板Grad-ProbAsk作者 (桶三洨!!!)時間14年前 (2011/10/03 22:29), 編輯推噓3(302)
留言5則, 3人參與, 最新討論串3/3 (看更多)
Consider the emitter diffusion capacitance Cde of a BJT. Which of the following statements is correct? (a)If the emitter current increase , Cde decrease. (b)If the base width increase,Cde decrease. (c)The large the value of Cde,the smaller the unity-gain frequency fT. (d)If the BJT is operated in the active region,Cde is smaller than the collector junction capacitance. 答案是給C 不過我是覺得B 有大大可以幫忙解惑嗎? -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 218.164.49.223

10/03 22:56, , 1F
我想Cde正比穿越時間 所以應該是增加
10/03 22:56, 1F

10/03 22:59, , 2F
fT=gm/Cde+Cje+Cu , Cde增加 fT減少
10/03 22:59, 2F

10/03 23:18, , 3F
Cde增加 gm也會增加
10/03 23:18, 3F

10/04 23:59, , 4F
B一定是錯的 Cde=基極穿越時間*gm 基極穿越時間是
10/04 23:59, 4F

10/05 00:05, , 5F
wb^2/2*Dn
10/05 00:05, 5F
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