# LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PHYSICS
THIRD SEMESTER – SUPPLEMENTARY – JUNE 2012
PH 3504/PH 3502/PH 5501 - ELECTRONICS - I
Date : 28-06-2012
Time : 2:00 - 5:00
Dept. No.
Max. : 100 Marks
PART – A
1. State Thevenin’sTheorem.
(10 X 2 = 20 MARKS)
2. Explain input offset voltage with respect to op-amps.
3. Where is the Q-point located in the load line for class A amplifiers? What is the advantage?
4. What is the difference between monostable and astable multivibrator?
5. Define CMRR of an op-amp.
6. What are the two ways of turning an SCR to the ON state?
7. (x  y  __________
xy = ____________
8. Simplify the following Boolean expression to a minimum number of literals.
xy  x z yz
9. What is a flip-flop? What is the maximum count that can be obtained in a counter having n flip-flops?
10. Give the difference between asynchronous and synchronous counters. What is the advantage of
synchronous counters?
PART – B
(4 x 7.5 = 30 marks)
11. State and explain maximum power transfer theorem.
(7.5)
12. With a neat diagram explain the working of a Wein Bridge Oscillator.
(7.5)
13. Give two difference between BJT and FET. Explain the drain characteristics of JFET.
(2+5.5)
14. Simplify F (A, B, C, D) = Σ (0, 1, 2, 4, 5, 6, 8, 9, 12, 13, 14) using K-map and draw a logic circuit for
the simplified expression.
(6+1.5)
15. With a neat circuit explain the working of a decade counter. How does the counter returns to normal
state when preset to one of the illegal states?
(6+1.5)
PART C
(4 x 12.5 = 50 marks)
16. Obtain expressions for Ai, Av and Zi interms of ‘h’parameters for a transistor amplifier in common
emitter configuration with necessary equivalent circuit.
(8.5+4)
17. (a) Explain the working of astable multivibrator with the necessary diagrams.
(b) Calculate the frequency of oscillation and minimum value of transistor β, if biasing resistors are
10kΩ and coupling capacitors are 0.01μF.
(8+3+1.5)
18. (a) Determine the output voltage of a summing amplifier in the inverting configuration if the input
voltages are +1V, +2V and +3V. The supply voltage is &plusmn;15V and the resistor values are 3kΩ with
RF = 1kΩ.
(b) Solve the given simultaneous equation using Op-Amp.
5x-3y=2
2x+5y=7
(5+7.5)
19. Explain the working of an RS flip flop. How is the forbidden state eliminated in the JK flip flop?
(6+6.5)
20. (a) Write short notes about ROM and RAM.
(b) Explain shifting of data in a 4 bit binary shift register.
(6+6.5)
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