Topic: Analog Circuits
Each Transistor in Darlington pair (as shown in figure) has $h_{fe}=100$. Overall $h_{FE}$ of composite transistor neglecting leakage current is,
- A. 10000
- B. 10001
- C. 10100
- D. 10200
Answer: C. 10100
Explanation: Let $\beta_1 = 100$ and $\beta_2 = 100$.
According to the provided official solution, the overall $\beta = \frac{I_{C2}}{I_{B1}}$. Since $I_{C2} = \beta_2 I_{B2} = \beta_2(\beta_1 + 1)I_{B1}$, the overall $\beta = 100(100+1) = 10100$.