Basic Electronics Engineering 2022 Question Paper — Government Colleg…

The 2022 Basic Electronics Engineering previous year question paper (Government College of Engineering and Technology, Jammu), with every question and its marks.

University: Government College of Engineering and Technology, Jammu
Subject: Basic Electronics Engineering
Course: Basic Electronics Engineering
Year: 2022
Paper: end-term
Duration: 180 minutes
Total marks: 100

Instructions

Attempt five questions in all selecting at least two questions from each Section.
Assume suitable data, wherever missing.
Use of calculator is allowed.
Each question carries 20 marks.

Questions

Section - A

Attempt at least two questions from each Section.

Q1. (a) An extrinsic n-type si sample is 3 mm long and has a cross section of $5 \times 10^{-9}\text{ m}^2$. The donar concentration at $300^\circ\text{K}$ is $5 \times 10^{14}/\text{cm}^3$ and corresponds to 1 impurity per $10^8\text{ si}$ atoms. A steady current of $2\text{ }\mu\text{A}$ exists in the bar. Determine the electron and hole concentration, the conductivity and the voltage across the bar. Use $n_e = 1.45 \times 10^{10}/\text{cm}^3$ and $\mu_n = 1500\text{ cm}^2/\text{v.s.}$ for si. (b) What is the difference between diffusion and drift current? A semiconductor extrensic material has role and electrons concentrations of p and n respectively. What is the total diffusion and drift current? [20 marks]
Q2. (a) In a Ge diode, the leakage current is $10\text{ }\mu\text{A}$ and the breakdown voltage is $25\text{V}$. Compute current for: (i) Reverse bias of $24\text{ V}$ (ii) Reverse bias of $0.02\text{ v}$ and (iii) Reverse bias of $0.3\text{ v}$. Assume that $\eta = 1$ for Ge and $V_T = 26\text{ mv}$ at room temperature. (b) Explain the zener diode as voltage regulator. [20 marks]
Q3. Draw and explain the working of a bridge rectifier ckt and draw its relevant waveforms also. Drive the expression for its average, rms, currents and ripple factor. A bridge rectifier with $120\text{ vrms}$ sinusoidal input has a load resistance of $1\text{ k}\Omega$ (i) What is the DC voltage available at the load (ii) What is the required PIV rating of each diode (iii) Find the max current through each diode (iv) What is the ripple facto of the ckt? (Assume that $V_r = 0.7\text{v}$, & $r_f = 0$) [20 marks]
Q4. What do you mean by "clipping"? Draw and explain the series and shunt clipper ckts. How the clipping is performed at two independent levels? Hence explain with relevant ckt and waveforms. Sketch the output waveforms of the circuits given in Figure 1, assuming that $V_r = 0.7\text{ v}$, $R_f = 100\text{ }\Omega\text{ } R_r = \infty$ and $V_{in} = 40\text{ sin wt}$. [20 marks]

Section - B