Firstranker's choice
USN
--- Content provided by FirstRanker.com ---
CHIKODI
KLE Society's
College of Engg & Tec
10ELN 15/25
First/Second Semester B.E. Degree Examination, June/July 2014
--- Content provided by FirstRanker.com ---
Basic Electronics
Time: 3 hrs.
Max. Marks:100
Note: 1. Answer any FIVE full questions, choosing at least two from each part.
2. Answer all objective type questions only in OMR sheet page 5 of the answer booklet.
--- Content provided by FirstRanker.com ---
3. Answer to objective type questions on sheets other than OMR will not be valued.
PART — A
1 a. Choose the correct answers for the following : (04 Marks)
i) Zener diode can be used for rectification. This statement is
A) true B) false C) neither true nor false D) none of these
--- Content provided by FirstRanker.com ---
ii) The maximum efficiency of full wave rectifier is
A) 40.6% B) 60.4% C) 78.5% D) 81.2%
iii) The knee voltage of a silicon diode is
A) 0.3V B) 0.5V C) 0.7V D) none of these
iv) If f Hz is the frequency of the input given to a half wave rectifier, the output frequency will be
--- Content provided by FirstRanker.com ---
A) 2f Hz B) f Hz C) 3f Hz D) 0.5f Hz
b. Draw and explain the VI — characteristics of a Si-diode and Ge-diode. (06 Marks)
c. With a neat circuit diagram, explain the working principles of full wave bridge rectifier and show that the ripple factor = 0.48, and efficiency = 81.2%. (10 Marks)
2 a. Choose the correct answers for the following : (04 Marks)
i) The current conduction in BJT is because of
--- Content provided by FirstRanker.com ---
A) electrons B) holes C) both electrons and holes D) none of these
ii) If a = 0.95, then the value of ß transistor is
A) 0.05 B) 19 C) 100 D) 120
iii) Common collector arrangement is generally used for
A) impedance matching B) voltage amplification C) current amplifier D) none of these
--- Content provided by FirstRanker.com ---
iv) The current relationship between two current gain in a transistor is
A) ß = a / 1-a B) ß = 1+a / 1-a C) ß = 1-a / 1+a D) ß = 1+ß / 1-a
b. Draw input and output characteristics of an NPN transistor in common base configuration and explain. (10 Marks)
c. For a Silicon transistor a = 0.995, emitter current is 10 mA and leakage current ICBO is 0.5µA. Find IC, IB, ß and ICEO. (06 Marks)
--- Content provided by FirstRanker.com ---
K.L.E. Society's
CHIKODI
College of Engg & Tec
10ELN 15/25
3 a. Choose the correct answers for the following : (04 Marks)
--- Content provided by FirstRanker.com ---
i) Which of the following factor affects the Q-point stability?
A) ICO B) coupling capacitor C) emitter resistor D) bypass capacitor
ii) The inter section of the dc load line with given base current curve is the
A) h-point B) D-point C) Q-point D) none of these
iii) For an emitter follower, the voltage gain is
--- Content provided by FirstRanker.com ---
A) unity B) greater than unity C) less than unity D) zero
iv) The best biasing stability is achieved by using biasing method.
A) fixed B) collector to base C) voltage divider D) none of these
b. Explain the working of collector-to-base bias circuit using an NPN transistor and derive the equation for IB. (08 Marks)
c. Define stability factor and discuss the factors that cause instability of biasing circuits. (08 Marks)
--- Content provided by FirstRanker.com ---
4 a. Choose the correct answers for the following (04 Marks)
i) FET is a __________ controlled device.
A) voltage B) current C) pulse D) power
ii) PNPN device is an
A) UJT B) SCR C) MOSFET D) MODFET
--- Content provided by FirstRanker.com ---
iii) __________ used as a relaxation oscillator.
A) MOSFET B) SCR C) BJT D) UJT
iv) The intrinsic standoff ratio of UJT
A) equal to one B) must be less than unity C) must be greater than unity D) must be zero
4 b. Explain the working of two transistor model of an SCR and obtain the expression for the anode current. (08 Marks)
--- Content provided by FirstRanker.com ---
c. Draw the equivalent circuit and VI-characteristic of UJT and explain it. (08 Marks)
PART - B
5 a. Choose the correct answers for the following: (04 Marks)
i) Oscillator uses __________ type of feedback.
A) positive B) negative C) reverse D) both A and B
--- Content provided by FirstRanker.com ---
ii) The frequency of oscillations in an oscillator is given by
A) 2pLC B) 2pvLC C) 1 / 2pLC D) 1 / 2pvLC
iii) With negative feedback, the bandwidth of an amplifier
A) decreases B) increases C) constant D) both A and B
iv) The magnitude voltage gain at half power frequencies of an RC coupled amplifier is __________ times maximum voltage gain.
--- Content provided by FirstRanker.com ---
A) 0.707 B) 7.07 C) 10 D) 17.06
b. Draw the frequency response of an RC-coupled amplifier and explain it. Mention its advantages and disadvantages. (08 Marks)
c. Explain with the help of circuit diagram the working of an RC phase shift oscillator using transistor. (06 Marks)
d. In a transistor colpitts oscillator having tank circuit parameters as c1 = 0.001 µF and c2 = 0.01 pF if L = 5µH, calculate the frequency of oscillations. (02 Marks)
--- Content provided by FirstRanker.com ---
6 a. Choose the correct answer; (04 Marks)
i) The gain of the voltage follower is
A) zero B) infinite C) negative D) unity
ii) Ideally open loop gain of op-amp is
A) 0 B) 1 C) 8 D) positive
--- Content provided by FirstRanker.com ---
iii) The CMRR is given by
A) Ad x Ac B) Ac /Ad C) Ad/Ac D) none of these
iv) Maximum rate of change of output voltage with time is called
A) CMRR B) slew rate C) over rate D) none of these
b. List the characteristics of an ideal-op-amp and draw the three input inverting summer circuit using an op-amp and derive an expression for output voltage. (08 Marks)
--- Content provided by FirstRanker.com ---
c. Draw the basic block diagram of a cathode ray tube and explain its working. (08 Marks)
7 a. Choose the correct answers for the following : (04 Marks)
i) Two's compliant of (1001)2 is
A) 1001 B) 0010 C) 0111 D) 1010
ii) To represent 35 in binary, number of bits required is
--- Content provided by FirstRanker.com ---
A) 6 B) 5 C) 4 D) 33
iii) Decimal number 37 is represented in BCD by
A) 100111 B) 00111011 C) 00110111 D) 111100
iv) Over modulation exists when modulation index is
A) 1 B) 0 C) >1 D) < 1
--- Content provided by FirstRanker.com ---
b. Explain the need for modulation. (06 Marks)
c. Convert (A3B)16 = ( )10, and (247.75)10= ( )8 (04 Marks)
d. i) Perform (FC02A)16 – (D052)16, using 16's complement.
ii) Subtract (4317.64)8 from (42.345)8 using 8's complement. (06 Marks)
8 a. Choose the correct answers for the following : (04 Marks)
--- Content provided by FirstRanker.com ---
i) The expression for half adder carry with input A and B is given by
A) A + B B) AB C) A B D) none of these
ii) The complement of A + B + 1 is
A) 0 B) A + 1 C) AB + 1 D) 1
iii) ABCD + ABD is equal to
--- Content provided by FirstRanker.com ---
A) ABC B) ABC C) ABD D) ABD
iv) A + (A + B) + C is __________ law.
A) associative B) commutative C) distributive D) none of these
b. Design a full adder circuit and realize, using two half adders. (08 Marks)
c. Simplify the following expressions and implement using only NAND gates : (08 Marks)
--- Content provided by FirstRanker.com ---
i) Y = ABC + ABC + ABC + ABC
ii) Y = AB + AC
iii) Y = A + AB
--- Content provided by FirstRanker.com ---
This download link is referred from the post: VTU B.Tech 1st Year Last 10 Years 2011-2021 Question Papers