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REJINPAUL.COM IMPORTANT QUESTIONS

ANNA UNIVERSITY NOV/DEC 2013 EXAMS

EC2205 Electronic Circuits

Unit I

1. Explain in detail different types of biasing circuits.

2. Explain the need for biasing , Stability factor and Fixed bias circuit.

3. Explain the advantage of self bias (voltage divider bias) over other types of biasing.

4. Explain the various types of bias compensation techniques.

5. Explain biasing of FET and MOSFET

Unit II

1. Draw the hybrid model of CE configuration obtain its gain, input impedance compare the

performance of this amplifier with CC&CB configuration

2. Draw the circuit of a common source FET amplifier & explain its operation.

3. Briefly explain the operation of a Darlington emitter follower and also derive an expression for its performance measures

(16)

4. What is a differential amplifier? Explain its working in common mode operation. Obtain its

AC equivalent circuit & drive the expression for voltage gain

5. What are the methods to improve the CMRR of differential amplifier? Detail any two of them.

Unit III

1. Derive the expression for the CE short circuit current gain of transistor at high frequency.

2. What is the effect of Cbe on the input circuit of a BJT amplifier at High frequencies? Derive the equation for gm which gives

the relation between

gm, Ic and temperature.

3. Draw the high frequency hybridp model for a transistor in the CE configuration and explain the significance of each

component.Derive an expression for its short circuit current gain.

4. Define fa,f and fT and state the relation between f and fT.Explain the significance of octaves and decades.

5. Define unity gain frequency. Obtain the necessary relation using transistor frequency response.

6. Derive the expression for Ai,Av,Zi,Yo,Ap for transistor amplifier using h parameter model.

Unit IV

1. Draw a neat circuit diagram of push-pull class-B amplifier. Explain its working.

2. For the transformercoupled class A power amplifier circuit derive the expression for its efficiency.

3. Prove that the maximum efficiency of class B amplifier is 78.5% and that of Class A type is 50%.

4. Compare class A, class B and class C power amplifier in their performance and efficiency.Give the design procedure for heat

sinks.

5. What is the difference between a voltage amplifier and a power amplifier? Discuss the advantage and disadvantage of a

complementary symmetry class B amplifier

6. With the help of neat diagram. Explain the characteristics of class A amplifier and also derive

an expression for its efficiency and figure of merit.

Unit V

1. Describe the working principle of full wave rectifier and derive the expression for the ripple factor ,rectifier

efficiency,Vdc,Idc,Vrms,Irms.

2. Draw the Hybrid (pie) model of transistor and derive the various parameters

3. Draw the block diagram of SMPS and explain its operation. Discuss its merits.

4.Distinguish between volatge regulator and voltage multiplier. Draw and explain the voltage regulator circuit.

Note : Problems can be asked from any units.