NEET Solved Paper 2016 Question 17
Question: A npn transistor is connected in common emitter configuration in a given amplifier. A load resistance of $ 800,\Omega $ is connected in the collector circuit and the voltage drop across it is 0.8 V. If the current amplification factor is 0.96 and the input resistance of the circuit is $ 192\Omega , $ the voltage gain and the power gain of the amplifier will respectively be :
Options:
A) 4, 3.84
B) 3.69, 3.84
C) 4, 4
D) 4, 3.69
Show Answer
Answer:
Correct Answer: A
Solution:
Given $ \alpha =0.96 $ So, $ \beta =\frac{\alpha }{1-\alpha }=\frac{0.96}{0.04}\Rightarrow $ Voltage gain for common emitter configuration $ A _{v}=\beta .\frac{R _{L}}{R _{i}}=24\times \frac{800}{192}=100 $
Power gain for common emitter configuration $ P _{v}=\beta A _{v}=24\times 100=2400 $
Voltage gain for common base configuration $ A _{v}=\alpha .\frac{R _{L}}{R _{P}}=0.96\times \frac{800}{192}=4 $
Power gain for common base configuration $ P _{v}=A _{v}\alpha =4\times 0.96=3.84 $
*In the question it is asked about common emitter configuration but we got above answer for common base configuration.
