Question

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

• A. $5\times {10}^4,5\times {10}^6$
• B. $5\times {10}^4,2.5\times {10}^6$
• C. $5\times {10}^4,5\times {10}^5$
• D. $2.5\times {10}^4,2.5\times {10}^6$

Answer 1

The correct option is B $5\times {10}^4,2.5\times {10}^6$

Voltage gain is given by
$V_{gain}=\left(\frac{\Delta I_C}{\Delta I_B}\right)\frac{R_{out}}{R_{in}}$

$V_{gain}=\left(\frac{5\times {10}^{-3}}{100\times {10}^{-6}}\right)\times {10}^3$

$V_{gain}=\frac{1}{20}\times {10}^6=5\times {10}^4$

Power gain is

$P_{gain}=\left(\frac{\Delta I_C}{\Delta I_B}\right)\left(V_{gain}\right)$

$P_{gain}=\left(\frac{5\times {10}^{-3}}{100\times {10}^{-6}}\right)(5\times {10}^4)=2.5\times {10}^6$

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