Discussion :: BJT Amplifiers - General Questions (Q.No.21)
Refer to this figure. Calculate the value of Rin(tot).
Answer: Option B
No answer description available for this question.
|K.Rekha said: (Sep 27, 2012)|
|Because range of out put impedance is 40 kilo ohms to 50 kilo ohms. So above options which value is nearer to the resistance that is correct answer.|
|Anil From Iiit Basar,Civil said: (Feb 22, 2013)|
|Zi = RB||Zb where Zb = beta.re+(1+beta)RE
Zb = (100*4.34)+(1+100)*0.5= 486k ohms
Zi = 4.07k || 486k = 3.77k ohms.
|Tuan Tieu said: (Apr 16, 2014)|
|Without bypass capacitor, we have:
Rin(base) = beta x (r'e + RE ) = 100 x (6 + 500) = 50k.
Rin(total) = R1 || R2 || Rin(base) = 3.767 kOhm.
|Fibo said: (Feb 22, 2017)|
|Where did you get the value of r'e?|
|Divya said: (Sep 3, 2017)|
|How to find the RE?|
|Charl said: (Sep 29, 2017)|
|re' = 26mV (voltage @ room temp) divided by Ie.
Ie = (Vb - Vbe) / RE = (3.7V - 0.7)/500
Get the value of Vb by using voltage divider equation.
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