Semiconductor Electronics Materials Devices And Simple Circuits Ques 79
79. 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
[2010, 2007]
(a) $500$
(b) $1000$
(c) $1250$
(d) $50$
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Answer:
Correct Answer: 79.(c)
Solution:
- (c) Power gain $=$ voltage gain $\times$ current gain
$=V_G \cdot I_G=\frac{V_0}{V_i} \cdot \frac{I_0}{I_i}$
$=\frac{V_0^{2}}{V_i^{2}} \cdot \frac{R_i}{R_0}=50 \times 50 \times \frac{100}{200}$
$=\frac{2500}{2}=1250$
BETA
