Question

In case of a common emitter transistor amplifier, the ratio of the collector current to the emitter current $\frac{I_C}{I_E}$ is $0.96$. The current gain of the amplifier is

• A. $6$
• B. $48$
• C. $24$
• D. $12$

Answer 1

The correct option is C $24$

Given,

$\frac{I_C}{I_E}=0.96$

$\Rightarrow I_C=0.96I_E...\left(i\right)$

Also, we know,
$I_E=I_B+I_C$

$\Rightarrow I_E=I_B+0.96I_E$ ............[from $\left(i\right)]$

$\Rightarrow I_B=0.04I_E...\left(ii\right)$

Current gain for common emitter amplifier,

$\beta =\frac{I_C}{I_B}=\frac{0.96I_E}{0.04I_E}=24$

Hence, $\left(C\right)$ is the correct answer.

$$\begin{array}{c}\text{Why this question?}\\ \text{Key Concept: For any configuration of transistor}\\ I_E=I_B+I_C\end{array}$$