Semiconductor Electronics Materials Devices and Simple Circuits - Result Question 65

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67. In a $C E$ transistor amplifier, the audio signal voltage across the collector resistance of $2 k \Omega$ is $2 V$. If the base resistance is $1 k \Omega$ and the current amplification of the transistor is 100, the input signal voltage is :

======= ####67. In a $C E$ transistor amplifier, the audio signal voltage across the collector resistance of $2 k \Omega$ is $2 V$. If the base resistance is $1 k \Omega$ and the current amplification of the transistor is 100, the input signal voltage is :

3e0f7ab6f6a50373c3f2dbda6ca2533482a77bed:content/english/neet-pyq-chapterwise/physics/semiconductor-electronics-materials-devices-and-simple-circuits/semiconductor-electronics-materials-devices-and-simple-circuits—result-question-65.md (a) $0.1 V$

(b) $1.0 V$

(c) $1 mV$

(d) $10 mV$

[2012]

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Answer:

Correct Answer: 67. (d)

Solution:

  1. (d) From the figure,

The output voltage, across the load $R_C$

$V_0=I_C R_C=2$

The collector current $(I_C)$

$I_C=\frac{2}{2 \times 10^{3}}=10^{-3} Amp$

Current gain $(\beta)$

$(\beta)$ current gain $=\frac{I_C}{I_B}=100$

$I_B=\frac{I_C}{100}=\frac{10^{-3}}{100}=10^{-5} Amp$

Input voltage $(V_i)$

$V_i=R_B I_B=1 \times 10^{3} \times 10^{-5}=10^{-2} Volt$

$V_i=10 mV$