JNTU B Tech 2nd Semester Examinations, Basic Electronics, Apr/May 2008

JNTU B.Tech II Semester Examinations,

                                                                                                                    Basic  Electronics,

 Apr/May 2008

(Metallurgy & Material Technology)

Time: 3 hours Max Marks: 80

Answer any FIVE Questions

All Questions carry equal marks


1. (a) Draw the circuit of Bridge rectifier and explain the working of it. Give the advantages and drawbacks of this circuit.

(b) Compare the performance of C, L- section and ? – section filters with reference to the rectifier circuits. [10+6]


2. (a) Draw the circuit of a P N P transistor in CC configuration and give the special features of this type of circuit.

(b) The emitter current IE in a transistor is 2 ma. If the leakage current ICBO is 5 ? a and ?dc = 0.985 calculate the collector current.

(c) Give the applications of J F E T. [6+6+4]


3. (a) Name different methods of turning-on of SCR.

(b) What are the important points to be noted while designing the gate-control circuit of SCR.

(c) Draw and explain the V-I characteristics of SCR. [2+6+8]


4. (a) Distinguish between open-loop or non feedback system and closed-loop or feedback system.

(b) An amplifier with Zi = 1 k has a gain of 1000. Calculate the feedback factor required to reduce the gain to 100 with negative feedback. Also calculate the input impedance of the feedback amplifier. [6+10]


5. (a) Draw the circuit of transistor Colpitts Oscillator and briefly explain the working of it. Derive the expression for frequency of oscillation fo.

(b) Calculate the frequency of oscillation of a transistor Colpitts Oscillator having

C1 = 0.02 ?F, C2 = 0.2 ?F and L = 10 ?H. [10+6]


6. (a) Classify timers according to the function and the techniques used.

(b) Draw the circuit and explain the working of “Magnetic Energy StorageWelder”. [8+8]


7. (a) Give the block diagram of Cathode Ray Oscilloscope (C R O) and explain each block in detail.

(b) Explain the principle of Dielectric Heating.

(c) Explain thermal effects of Ultrasonic waves. [8+4+4]


8. (a) Explain in detail the various addressing modes used in 8085 Microprocessor with examples.

(b) What is a Microprocessor? [12+4]

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