For $CE$ transistor amplifier, the audio signal voltage across the collector resistance of $2 k \Omega$ is $4\, V$. If the current amplification factor of the transistor is $100$ and the base resistance is $1 \, k\Omega$, then the input signal voltage is
- 10 mV
- 20 mV
- 30 mV
- 15 mV
The Correct Option is B
Solution and Explanation
Voltage Gain Calculation
Given values:
- \(\beta = 100\)
- \(R_C = 2 \, k \Omega\)
- \(v_0 = 4 \, V\)
- \(R_B = 1 \, k \Omega\)
The voltage gain (A) is given by:
\(A = \frac{v_0}{v_i} = \beta \frac{R_C}{R_B}\)
Now, solving for input voltage \(v_i\)
\(v_i = \frac{v_0 \times R_B}{\beta R_C}\)
Substitute the given values:
\(v_i = \frac{4 \times 10}{100 \times 2 \times 10^3} = 20 \, mV\)
Conclusion:
The input voltage \(v_i\) is 20 mV.
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Concepts Used:
Semiconductors
Semiconductors are a crystalline solid materials, whose electrical conductivity lies between a conductor and an insulator. Semiconductors are mainly used in the manufacturing of electronic devices like capacitors, transistors, diodes, Integrated circuits, etc.
Properties of Semiconductor:
- Semiconductor acts like an insulator at Zero Kelvin. On increasing the temperature, it works as a conductor.
- Due to their exceptional electrical properties, semiconductors can be modified by doping to make semiconductor devices suitable for energy conversion, switches, and amplifiers.
- Lesser power losses.
Uses of Semiconductor:
- Semiconductors are widely used in manufacturing electronics devices like transistors, diodes, sensors, integrated circuits.
- Semiconductors are widely used in all electronic devices, like mobile phones, digital cameras, communication devices, trains, ATMs, etc.