Question

In a common emitter amplifier, the load resistance of the output circuit is $1000$ times the resistance of the input circuit. If $\alpha =$ $0.98$, the voltage gain is

• A. $98000$
• B. $49000$
• C. $9800$
• D. $4900$

Answer 1

The correct option is B $49000$

Given that:
$R_L=1000R_i$
$\alpha =0.98$
For transistors,
$\beta =\frac{\alpha }{1-\alpha }$

$\beta =\frac{0.98}{1-0.98}=49$

Now,
Voltage gain = $\beta \times$ Resistance gain

Voltage gain = $\beta \times \frac{R_L}{R_i}$

Voltage gain = $49\times \frac{1000R_i}{R_i}$

Voltage gain = $49000$