LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PHYSICS
THIRD SEMESTER – APRIL 2012
PH 3504/PH 3502/PH 5501 – ELECTRONICS – I
Date : 24-04-2012 Dept. No. Max. : 100 Marks
Time : 9:00 – 12:00
PART –A
Answer all questions: (10 x 2 = 20)
- A DC source generating 500 V has an internal resistance of 1000 Ω. Find the load current if load resistance is 50 Ω and 100 Ω.
- State the condition for transfer of maximum power from a source to load.
- What is the need for biasing a transistor?
- What is a multivibrator?
- Define CMRR.
- Give the basic construction of UJT.
- Give the block diagram of a multiplexer.
- Draw the logic symbol and truth table for T flip flop.
- What is a shift register?
- Write a brief note on RAM.
PART – B
Answer any FOUR questions: (4 x 7.5 = 30 marks)
- Use the principle of superposition to find the current in the 4 Ω resistor in the circuit given below:
- Discuss the working of RC coupled amplifier with a neat circuit diagram.
- Explain how op-amp can be used as a summing and difference amplifier.
- Discuss the construction and working of 4 bit a parallel binary adder.
- Design the logic circuit for 3 bit down counter and explain its working with the help of truth table.
PART – C
Answer any FOUR questions: (4 x 12.5 = 50 marks)
- Obtain the general expression for input impedance, current gain and voltage gain of a transistor in terms of h parameters and load resistance. Deduce the same for a transistor used in CE mode.
- a) Explain the principle of phase shift oscillator and describe its working with a neat
diagram.
- b) Describe the working of bistable multivibrator. (7 + 5.5)
- Describe the construction and working of SCR. Also explain how it can be used as an half wave rectifier.
- With a neat circuit diagram and truth table describe the operation of a J-K Master Slave flip flop.
- Discuss the working of a bi-directional shift register with a neat block diagram.
LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PHYSICS
FIFTH SEMESTER – APRIL 2012
PH 5404/5401 – ELECTRONICS – II
Date : 27-04-2012 Dept. No. Max. : 100 Marks
Time : 1:00 – 4:00
PART – A
Answer ALL questions (10×2=20)
- Write a short note on logarithmic amplifier.
- Calculate the cut off frequency for a second order high pass filter given R2 =10 kΩ,
R3 =10 kΩ, C2= 1µF, C3 =1µF, R1 = 20kΩ, R2=10kΩ. - Differentiate analog and digital signals
- What is meant by accuracy in a D/A converter?
- What is meant by etching in IC terminology?
- What is VLSI?
- What is PSW?
- State the difference between ADD and ADC instructions of 8085.
- Define opcode and operand.
- Write a program to add 05 and 04 by immediate mode of addressing in microprocessor 8085.
PART – B
Answer any FOUR questions (4×7.5 = 30)
- Solve the following differential equation using operational amplifiers. d2y/dt2 2dy/dt+3y–1=0.
- Explain with circuit the working of OP-AMP based integrator.
- Discuss with a neat diagram the working of a counter type A/D converter.
- What is addressing? Explain in detail about the different addressing modes in µP 8085.
- Write an assembly language program to determine the smallest number in an array of 10 numbers.
PART – C
Answer any FOUR questions (4×12.5 =50)
- With a neat diagram explain in detail the working of an OP-AMP based monostable multivibrator. Obtain the expression of the pulse width.
- (a) Explain with circuit, the working of a 4 bit binary weighted D/A converter with OP-AMP (6.5)
(b) For a 4 bit binary weighted resistor D/A converter determine the following (i) output voltage when MSB is set. (ii) Output voltage for 1011 (iii) Full scale voltage. Assume 0=0V and 1=5V. Rf=R/8 (6)
- (a) Discuss in detail the fabrication of resistor. (6.5)
(b) Write short notes on linear and non-linear integrated circuits. (6)
- Explain in detail about the classification of instruction sets in microprocessor 8085.
- Write an assembly language program to evaluate the expression x2+xy+y2 using subroutine.
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