# RGPV Exams Questions Papers – 3rd SEM. – Dec- 2004, Electronics

B.E. (Third semester) EXAMINATION, DEC, 2004

(Common for EC/EE/IP Engg.)

(ELECTRONICS)

(EE/EC/EX-304)

Note:      Attempt any five questions.  All question carry equal marks. Assume any data  missing.

1. (a) Explain the V-1 characteristics of zener diode and explain its working as a voltage regulator .

(b)  Define the pinch off voltage V p. Sketch the depletion region before and after pinch off. How does

FET behaves in the region  before and after pinch off ?

2. (a) Distinguish between positive feedback and negative feedback . List the characteristics of an

amplifier that get modified by negative feedback.

(b)  Explain the Wien’s  bridge oscillator using BJT. For this circuit calculate the frequency of

oscillation.

3. (a) Draw a self bias circuit for a transistor . Why these circuit has an improvement on fixed bias circuit

? How the load line is drawn in self bias circuit.

(b)    Determine the d.c. bias voltage V CE   And the current IC From the circuit given below :

4. (a) Give the characteristics of class- A power amplifier . Deduce the expressions where necessary.

(b)   A transformer coupled class – A amplifier , maximum collector current charge is 100 mA ; VCC =10 .

Find the power transferred to 4 ohm speaker load if it is

(i) Direct coupled (ii) Transformer coupled (Find the turn ratio of transformer)

5. (a) Draw the circuit of Bitable multavibrator . Explain its working.

(b)  What is voltage comparator ? How to generate a saw-tooth using op-amps ?

6. (a) Explain the operation of a transistorized differential amplifier . Show the input bias currents clearly

and how input offset current can be minimized ?

(b)  What are the characteristics of an ideal Op-Amp . Derive the formulas for inverting and non-verging

amplifiers.

7. (a) Explain V-1 characteristics of SCR . What is meant by Gate on and Off times ?

(b)  Explain the operation and application  of convertor . invertors and choppers circuits.

8.     Write short notes on any three of the following  :

(a) Varactor diode

(b) h-parameter