Question

A common emitter amplifier has a voltage gain of $50$, an input impedance of $100\Omega$ and an output impedance of $200\Omega$. The power gain of the amplifier is

• A. $500$
• B. $1000$
• C. $1250$
• D. $50$

Answer 1

The correct option is C

$1250$

Step 1: Given data.

Common-emitter amplifier.

Voltage gain $=$ $50$

Input impedance, $R_{in}=100\Omega$

Output impedance, $R_{out}=200\Omega$

Step 2: Finding the power gain of the amplifier.

Formula used:

Power gain$=\frac{{\left(Voltagegain\right)}^2}{Resis\tan cegain}$

We know that

Resistance gain $=\frac{R_{out}}{R_{in}}$$=\frac{200}{100}$$=2$

Now,

Power gain $=\frac{{\left(Voltagegain\right)}^2}{Resis\tan cegain}$$=\frac{{50}^2}{2}$ $=1250$

Hence, option C is correct.