# An npn transistor operates as a common emitter

Question:

An npn transistor operates as a common emitter amplifier with a power gain of $10^{6}$. The input circuit resistance is $100 \Omega$ and the output load resistance is $10 \mathrm{~K} \Omega$. The common emitter current gain ' $\beta$ ' will be_______ . (Round off to the Nearest Integer)

Solution:

$10^{6}=\beta^{2} \times \frac{R_{0}}{R_{i}}$

$10^{6}=\beta^{2} \times \frac{10^{4}}{10^{2}}$

$\beta^{2}=10^{4} \Rightarrow \beta=100$