Electronics and Communication Engineering - Exam Questions Papers - Discussion

Discussion Forum : Exam Questions Papers - Exam Paper 3 (Q.No. 45)
45.
A bipolar differential amplifier uses a transistor having β0 = 200, ICQ = 100 mA, |Adm| = 500 and CMRR = 80 dB. The value of Rc and RE will be respectively __________ .
1.25 kΩ, 1.25 MΩ
125 kΩ, 1.25 MΩ
1.25 MΩ, 1.25 kΩ
3.25 kΩ, 3.25 MΩ
Answer: Option
Explanation:

80 = 20 log CMRR

CMRR = 10000

But CMRR = 2gmRE

= 1.25 MΩ

Adm = - gmRC

= 1.25 KΩ.

Discussion:
2 comments Page 1 of 1.

Sitharam said:   8 years ago
How could you tell VT=25?

Can anyone explain?

Marcus Liwag said:   1 decade ago
Shouldn't Re be 1.25k ohms and Rc 125 ohms?

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