Q. In a CE transistor amplifier, the audio signal voltage across the collector resistance of $2k\Omega$ is $2V$. If the base resistance is $1k\Omega$ and the current amplification of the transistor is 100, the input signal voltage is
A) 0.1 $V$
B) 1.0 $V$
C) $1\ mV$
D) 10 $mV$
Explanation
(d) [image:14_image236.emf]
$V_{0} = I_{c}R_{c} = 2$
$I_{c} = \frac{2}{2 \times 10^{3}} = 10^{- 3}\ Amp$
Current gain $= \frac{I_{C}}{I_{B}} = 100$
$I_{B} = \frac{I_{C}}{100} = \frac{10^{- 3}}{100} = 10^{- 5}\ Amp$
$V_{i} = R_{B}I_{B} = 1 \times 10^{3} \times 10^{- 5} = 10^{- 2}\ Volt$
$= 10\ mV$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.