Important Questions in Electronic circuits-I ** **147304 subject for NOV/DEC 2011 AUT ANNA UNIVERSITY OF TECHNOLOGY EXAMINATIONS FOR SECOND YEAR THIRD SEMESTER ECE Students

147304 - Electronic circuits-I

UNIT I

1. Derive the stability factor for voltage divider bias

2. Expain the working principle of full wave rectifier circuit with Î filter.Derive its ripple factor

3. Explain the function of differential amplifer with neat circuit.Derive its Ad& Ac CMRR

4. Discuss the various for techniques of stabilzation of Q-point in a transistor

UNIT II

1. For the CC transistor amplifer circuit,find the expressions for input impedance and voltage gain. Assume suitable model for transistor

2. Discuss the working of a basic emitter coupled differential amplifer circuit

3. Briefly explain the drain to gate bias circuit for enhancement MOSFET

4. Derive the current gain Ai,input impendance Zi,voltage gain Av and output admittance Yo for a two port hybrid network

UNIT III

1. Describe the function of SMPS with suitable diagram

2. Explain the circuit which uses a diode to compensate for changes in Vbe and in Ico

3. Discuss the high frequency equivalent circuit of FET and hence derive gain bandwidth product for Any one configuration

4. Discuss the frequency response of multistage amplifers.calculate the overall upper and lower Cut-off frequencies

5. Discuss the terms rise time and sag.

UNIT IV

1. Draw the hybrid ∏ common emitter transistor model and derive the valves of various component of h- parameter

2. Sketch the small signal high frequency circuit of a common source amplifier and derive the expression for a voltage gain

3. Derive the theortical max conversion efficency of class B power amplifer

4. Describe the distortion in power amplifer and the methods to eliminate the same

UNIT V

1. Explain the circuit of voltage regulator and also discuss the short circuit protection Mechanism

2. Explain the power control method using SCR.

3. Prove that the maximum efficiency

(a)For class A transformer coupled power amplifier is 50% and (b) For class B amplifier is 78.5%

4. The loud speaker of 8Î© is connected to the secondary of the output transformer of a class Aamplifier circuit the quiescent collector current is 140 mA The turns ratio oe the transformer is 3:1 the collector supply voltage is 10V if ac power delivaried to the loud speaker is .48W assume ideal transformer calculate

(a)power developed across primary

(b)RMS value of load voltage

(c) RMS value of primary voltage

(d)RMS value of load current

(e) RMS value of primary current

(f) DC power input

(g)The efficiency

(h) power dissipation

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