Modern Physics Ques 9
- For a common-emitter configuration, if $\alpha$ and $\beta$ have their usual meanings, the incorrect relationship between $\alpha$ and $\beta$ is
(2016 Main)
(a) $\frac{1}{\alpha}=\frac{1}{\beta}+1$
(b) $\alpha=\frac{\beta}{1-\beta}$
(c) $\alpha=\frac{\beta}{1+\beta}$
(d) $\alpha=\frac{\beta^2}{1+\beta^2}$
Show Answer
Answer:
Correct Answer: 9.( b,d )
Solution:
$ \begin{array}{rlrl} & I_b+I_c =I_c \\ \Rightarrow & \frac{I_b}{I_c}+1 =\frac{I_c}{I_c} \\ \Rightarrow & \frac{1}{\beta}+1 =\frac{1}{\alpha} \\ \Rightarrow & \frac{1}{\alpha} =\frac{1+\beta}{\beta} \Rightarrow \alpha=\frac{\beta}{1+\beta} \end{array} $
BETA
