Punjab University 2005 B.Tech Electronics and Communications Engineering ANALOG ELECTRONICS - Question Paper

EC 202 fourth Sem May 2005
ANALOG ELECTRONICS
Note: part A is compulsory. Attempt any 4 ques. from part B and 2 from part C. presume any missing data

1.(10 *2=20)

1. Draw the high frequency equivalent circuit of CE transition.
2. Why does RC coupling provide constant gain over mid-frequency range?
3. discuss the difference ranging from a voltage and power amplifier.
4. What is crossover distortion? discuss in brief.
5. Show that maximum collector efficiency of class a transformer coupled power amplifier is 50%.
6. Why is negative feedback employed in high gain amplifiers?
7. elaborate practical applications of emitter follower?
8. Why is crystal oscillator used in radio transmitter?
9. Why is –ve feedback given in Wein-bridge oscillator?
10. How does zener diode maintain constant voltage across load in the breakdown region?

part B Marks five every
(5 *4=20)
2. discuss hybrid pi CE transistor model in detail.

3. discuss the push-pull amplifier circuit in detail with a neat diagram.

4. The gain and distortion of an amplifier are 150 and 5% respectively without feedback. If the stage has 10% of its output voltage applied as negative feedback, obtain the distortion of the amplifier with feedback.

5. A transformer coupling is used in the final stage of a multistage amplifier. If the output impedance of transistor is one k O, obtain the turn ratio of the transformer so that maximum power is transferred to the load.

6. discuss a current shunt feedback circuit and perform a suitable analysis.

part C Marks 10 every
(10 * 2=20)
7. What do you understand by class A, Class B and class C power amplifier? describe and discuss the subsequent terms as applied to power amplifiers:
(a) Collector efficiency
(b) Distortion
(c) Power dissipation capability

8 (a) A zener regulator has Vz=15V.The input voltage may vary from 22 V to 40 V and load current from 20 to 100 mA. To hold load voltage constant under all conditions, what should be the value of series resistance?
(b) discuss the working of a Colpitts oscillator with a neat diagram.

9. (a) Derive an expression for the gain of negative voltage feedback amplifier.
(b) A multistage amplifier consists of 3 stages. The voltage gain of stages are 60, 100 and 160 compute the overall

Earning:   Approval pending.