LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – PHYSICS

THIRD SEMESTER – APRIL 2011

PH 3504/PH 3502/PH 5501 – ELECTRONICS – I

 

 

 

Date : 12-04-2011              Dept. No.                                                    Max. : 100 Marks

Time : 1:00 – 4:00

PART – A

Answer ALL questions.                                                                                              (10 x 2 = 20 marks)

1. State Norton’s theorem.
2. State the conditions for oscillations in an Oscillator.
3. Define β. Show that β= α/ (1-α)
4. For an inverting amplifier using Op-Amp, R1=1K and Rf = 10 K. Assuming the
   amplifier to be ideal, calculate the output voltage for an input of 1V.
5. Define CMRR.
6. What is don’t care condition in K- map?
7. Construct the K-map for a 4-variable truth table in which the output is high for the
   following input conditions ABCD = 1101, 1010, 0101, 1111
8. What is a Multiplexer?
9. The terminal count of a MOD 13 binary counter is________ a)1111   b) 1101 c) 1100
   d) 0100
10. A 4-bit asynchronous counter uses Flip-Flops of propagation delay time 20 ns each.
    The maximum possible time required for change of state is  _________

a)60 ns   b) 20 ns   c)80 ns   d)40ns

PART – B

Answer ANY FOUR questions.                                                                                   (4 x 7.5 = 30 marks)

11.a)  Derive the condition for transfer of maximum power from a source to a load. (4)

3. b) A generator develops 200 V and has an internal resistance of 100 Ω. Find the
   power delivered to a load of 100 Ω. What is the efficiency?  (3.5)
4. With a neat diagram, explain the construction and working of a phase shift oscillator.
5. Derive expressions for the gain of inverting and non-inverting amplifiers using Op-
   Amp.                                                                                                                                             (3+4.5)

 

14. Draw the logic circuit of a Master- Slave flip-flop and explain its working. How is the
    race around problem overcome?
15. Explain with theory, the working of MOD7 asynchronous UP counter.

PART – C

Answer ANY FOUR questions.                                                                                 (4 x 12.5 = 50 marks)

16. Give the equivalent circuit of a CE amplifier using h- parameters. Hence derive expressions for Ai, Av and Zi in terms of h-parameters.   (4+8.5)
17. a) Explain the construction and working of Bistable Multivibrator with a neat diagram.
18. b) A  potential divider circuit has the following values. I_E = 2mA, I_B = 50 µA , V_BE =
    2 V, R_E= 1 k and R₂ = 10 k and V_CC = 10V. Find the value of R₁.                                                  (8+4.5)
19. a) Explain the working of averaging amplifier using Op-Amp.
20. b) Solve the given simultaneous equations using Op-Amps.

2  X  +   3Y =  14  and  2 X  – Y  = 4                                                                                       (5+7.5)

19. Simplify the Boolean function

F(A,B,C,D)   =  Σ_m (  1,3,7,11,15)  + Σ_d  (0,2,5 )

Implement the simplified expression as a logic diagram with only two input NAND
gates only.                                                                                                                                     (6+6.5)

20. Write detailed notes on:
21. a) Shift registers b) Read Only Memory and     c) Random Access Memory.            (4.5+4+4)

 

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