Question

The transfer characteristic curve of a transistor, having input and output resistances $100\Omega$ and $100\text{k}\Omega$ respectively, is shown in the figure. The voltage gain is

• A. $1\times {10}^4$
• B. $5\times {10}^4$
• C. $3\times {10}^4$
• D. $4\times {10}^4$

Answer 1

The correct option is B $5\times {10}^4$

Given,

From given curve,
$\Delta I_c=(10-5)\text{mA}=5\text{mA}=5\times {10}^{-3}\text{A}$

$\Delta I_B=(200-100)\mu \text{A}=100\mu \text{A}=1\times {10}^{-4}\text{A}$

So, we have
$\beta =\frac{\Delta I_C}{\Delta I_B}=\frac{5\times {10}^{-3}}{1\times {10}^{-4}}=50$

Also, $A_v=\beta \frac{r_o}{r_i}$

$\Rightarrow A_v=50\times \frac{100\times {10}^3}{100}=5\times {10}^4$

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