Basic Electronics - B.Tech 3rd Semester Special Exam., 2020

2020•Semester 2•Civil-CA•End Semester
Bihar Engineering University, Patna
B.Tech 3rd Semester Special Exam., 2020

Basic Electronics

Time: 03 HoursCode: ESC-202 (101302)Full Marks: 70

Instructions:

  1. The marks are indicated in the right-hand margin.
  2. There are NINE questions in this paper.
  3. Attempt FIVE questions in all.
  4. Question No. 1 is compulsory.
Q.1 Answer/Fill in the blanks/Write true or false (any seven):[2x7=14]

  1. Why is filter required to be added after rectifier circuit?

  2. What is the application of voltage regulator?

  3. DC value of pure AC waveform is ______.

  4. Which of the transistor currents is always the largest?

  5. What is the source of leakage current in a transistor?

  6. What is the major difference between a bipolar and a unipolar device?

  7. Give the advantage of negative feedback in amplifier.

  8. BUT amplifier changes the frequency and shape of the signal.

  9. CMMR for ideal operational amplifier is ______.

  10. Slew rate for ideal operational amplifier is ______.

Q.2 Solve both questions :[6+8=14]

  1. Draw volt-ampere characteristics of a Zener diode. What is meant by the knee voltage in the curve?

  2. Describe in detail the avalanche breakdown mechanism in a diode.

Q.3 Solve both questions :[6+8=14]

  1. Explain the principle of operation of LED with the help of diagram.

  2. Derive the expression for \( I_C \) in terms of \( I_E \) and \( \alpha_{dc} \) for a common-base BUT configuration. For a given \( \alpha_{dc} \) of 0.998, determine \( I_C \), if \( I_E = 4 \, \text{mA} \).

Q.4 Solve both questions :[5+9=14]

  1. Define the stability factor. What does smaller stability factor indicate?

  2. Derive the expression for stability factor for voltage divider bias (self-bias) circuit.

Q.5 Solve both questions :[7+7=14]

  1. Explain the construction and characteristics of FET.

  2. Draw and explain h-parameter small signal model for BJT.

Q.6 Solve both questions :[8+6=14]

  1. Explain the working of common emitter amplifier with the help of circuit diagram.

  2. What are the roles of coupling and bypass capacitors? Explain in detail.

Q.7 Solve both questions :[6+8=14]

  1. Describe the RC phase-shift oscillator with circuit diagram.

  2. Explain the working of high-frequency LC oscillator with the help of circuit diagram.

Q.8 Solve both questions :[7+7=14]

  1. Explain the working of voltage series feedback amplifier with the help of block diagram.

  2. Design an integrator using op-amp and explain its working.

Q.9 Solve both questions :[7+7=14]

  1. Write the circuit diagram of differential amplifier configurations and explain its working.

  2. Explain about CMRR, slew rate and concept of virtual ground.