Anna University, Chennai

**EC2205-ELECTRONIC ****CIRCUITS-I**

** ****UNIT-I**

PART B

1) How are dc and ac load lines draw on the output characteristic curves of on the output characteristics curves of an amplifier sketch them

&discuss

2) Explain thermistor compensation technique with neat diagram and explain self bias circuit using n-channel JFET

3) Derive expression for the various stability factors

4) Explain in detail about voltage divider bias circuit for FET

5) What is the need for biasing .explain the different types of biasing of

BJT?

6) Explain in detail about collector to base bias circuit of FET

7) Define 3 stability factors derive& explain the condition to avoid thermal run away

8) Describe the stability in fixed &self bias& compare their performance

9) Explain in detail about biasing of MOSFET

10) Show how a FET can be used as a voltage variable resistor

11) Draw the dc load line for the following transistor configuration obtain the quiescent point RC=330Ω, rb1=5.2k, rb2=1.24k, re=100Ω&B=100 Ω

12) Determine the values of circuit elements of collector to base bias circuit using vcc=29v, Vce=5v, β=45, IC=5 A

13) Explain how FET biasing differs from BJT? &write short notes on heat sink?

14) Design a voltage divider bias network using a supply of

24v,β=110&ICQ=4MA, VCEQ=8V choose ve=1/8 vcc

15) Compare different types of transistor configuration

16) Explain in the detail about CE configuration

**UNIT-II **

**PART B**

1) Explain the operation of the emitter coupled differential amplifier and

Discuss about the transfer characters of the differential amplifier

2) Explain bootstrapped Darlington circuit with neat sketch.

3) Explain the differential and common mode operation of transistorized differential amplifier.

4) Derive the expression for CE short circuit current gain and current gain with resistive load at high frequencies.

5) Derive the expression for the voltage gain of i) Common source amplifier

Common drain amplifier configurations, under small signal low frequency conditions.

6) Draw the Darlington emitter follower circuit and explain.

7) With small signal equivalent circuit of emitter follower; derive its input and output impedance.

8) Employ boot strapping technique in the emitter follower circuit and derive its input impedance.

9) Define CMRR. Explain the method used to improve CMRR.

10) Give the guidelines for the analysis of transistor circuit for its small signal behavior.Explain with an example.

11) Draw a two identical stage RC coupled amplifier and explain the need foreach component. Comment on its individual stage voltage gain and current gain. What happens to the overall value of the above gains?

12) In a darlingtonpair amplifier Re=100 ohms, If β1=100, β2=75,

calculate the overall impedance.

13) Draw a small signal low frequency model for an FET amplifier and explain.

14) Derive the input and output impedances of FET amplifier and explain about common collector amplifier.

15) Explain in detail about transformer coupled amplifier.

16) Explain in detail about direct coupled amplifier.

**UNIT-III**

1) Draw the high frequency equivalent circuit for a FET amplifier and derive the values of all the parameters.

2) Derive the expression for transistor conductance for hybrid? Common emitter transistor model.

3) What is the effect of Cbe ’ on the input circuit of a BJT amplifier at high frequencies.

4) Find the equivalent miller capacitance if the Cbc ’ is 10pf, CB current gain is 0.99, the small signal resistance is 26 ohms and the load resistor is 10 kohm.

5) How does base compensation help in broadcasting the bandwidth of an amplifier? Explain with necessary expressions.

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

7) Derive the expression for CE short circuit current gain of a transistor at high frequency.

8) Define alpha and beta cutoff frequency,rise time,bandwidth and transistion frequency and derive their values interms of circuit parameters.

9) Discuss the frequency response characteristics of CE amplifier. Derive the general expression for gain at low, middle, high frequencies. Draw the bode plots forlow and high frequencies.

10) Using hybrid pimodel. Derive the expression for short circuit current gain. Define Ft. Draw bode plot for short circuit current gain as a function of frequency.

11) Explain in detail about low frequency response of BJT amplifier.

12) Explain in detail about low frequency response of JFET amplifier.

13) Explain in detail about high frequency response of BJT amplifier.

14) Explain in detail about high frequency response of JFET amplifier.

**UNIT-IV**

**PART B**

1) Describe the operation of class c amplifier and derive the efficiency.

2) What is thermal runaway? What are design aspects that have to be taken care of While designing power amplifier to have thermal stability?

3) Calculate the efficiency of a classB amplifier with ac peak to peak voltage at output is

4) Prove that the maximum efficiency of class A transformer coupled power amplifier is 50% and that of class B type 78.5%.

5) Explain complementary symmetry power amplifier with neat diagram and give the design procedure for heat sinks.

6) Explain the transformer coupled audio power amplifier.

7) Explain the operation of class B push pull amplifier.

8) Explain the working of class D amplifier and explain about cross over distortion.

9) Give the procedure of heat sink, compare class A,B & AB power amplifiers is their performance& efficiency.

10) Draw the transform coupled class B amplifier using PNP transistors& explain its Operation.What is the modification done to alter it to function as a class AB amplifier?

11) Differentiate between voltage & power amplifier.

12) Explain in detail about RC coupled class & amplifier.

13) Explain in detail about different types of distortions in class B

amplifier.

14) Explain in detail about class AB amplifier.

**UNIT-V**

** PART B**

1) Explain how Zener diode acts as a regulator. explain its working. Derive the expression for ripple factor. variation of a linear voltage regulator. of 50mA. Assume any data required, but reasonably. Provide short circuit protection.

6) Explain in detail about half Wave rectifier circuit and compare their performance.

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

8) Explain in detail about Bridge rectifier circuit.

9) Describe in block diagram the series and shunt voltage regulator

10) How regulation of output voltage is obtained against line and load variation in SMPS.

11) Explain in detail the operation of the electronic voltage regulators.

12) Explain in detail about power controlled using SCR.

13) Explain in detail about different types of voltage multiplier.

14) Explain in detail about FullWave rectifier circuit. operation of transistorized series regulator.

15) Explain in detail about different types of filters.

16) Describe the regulation of the output voltage with respect to input voltage and load

17) Design a simple Zener regulator to give a DC fixed output of 5v to a load current

18) Draw the circuit diagram of a FWR with capacitor input filter. With suitable waveform

.