A transistor is used as a common emitter amplifier with a load resistance $2 \mathrm{k} \Omega$. The input…
A transistor is used as a common emitter amplifier with a load resistance $2 \mathrm{k} \Omega$. The input resistance is $150 \Omega$, Base current is changed by $20 \mu \mathrm{A}$ which results in a change in collector current by $1.5 \mathrm{~mA}$. The voltage gain of the amplifier is
$1100$
$1000$
$900$
$12000$
Solution
The correct option is (B).
Concept: The voltage gain is given by
$\beta=\frac{I_C}{I_B}=\frac{1.5 \mathrm{~mA}}{20 \mu \mathrm{A}}=75$
And the voltage gain can be written as,
$\frac{\mathrm{V}_0}{\mathrm{~V}_{\mathrm{i}}}=\beta \frac{\mathrm{R}_{\mathrm{L}}}{\mathrm{R}_{\mathrm{i}}}=75 \times \frac{2000}{150}=1000$
.