Code No: 07A3EC14 R07 Set No. 2

II B.Tech I Semester Examinations,December 2011ELECTRONICS CIRCUIT ANALYSIS

Common to Electronics And Telematics, Electronics And CommunicationEngineering

Time: 3 hours Max Marks: 80Answer any FIVE Questions

All Questions carry equal marks? ? ? ? ?

1. (a) Derive various Resistive parameters of Hybrid - π model of a transistor interms of h parameters.

(b) What is the relationship between fT and fβ? Discuss the significance of fT .[12+4]

2. (a) Differentiate between a tuned voltage amplifier and a basic voltage amplifier.Draw the circuits of both of them. Also draw their frequency responses?

(b) Explain why tuned amplifiers cannot be used for amplification of low frequen-cies? [10+6]

3. (a) State Miller’s theorem. Explain its significance in transistor circuit analysis.

(b) For the amplifier shown in figure3b, calculateRi, Ro, AV , AV Sand A’I = - I2 / I1.The h-parameter values are hfe = 50, hie = 1.1KΩ, hre = 2.5x10 - 4, hoe = 24 µA/V.

Figure 3b

4. (a) What are the advantages and disadvantages of push pull configuration? Showthat in Class-B push pull amplifier the maximum conversion efficiency is 78.5%

[8]

1

Code No: 07A3EC14 R07 Set No. 2

(b) A transistor in a transformer coupled (Class - A) power amplifier has to delivera maximum of 5 Watts to a load of 4Ω load. The quiescent point is adjusted forsymmetrical swing, and the collector supply voltage is VCC=20 Volts. AssumeVmin=0 volts.

i. What is the transformer turns ratio?

ii. What is the peak collector current? [8]

5. (a) Explain why voltage regulators are required for a DC power supply operatingfrom an AC source?

(b) If the DC output voltage is 600V with no load attached to power supply butdecreased to 400V at full-load find the percentage voltage regulation?

(c) For the circuit shown in figure5. If Vz=10V, β=100 and RL=100ohms. Findthe load voltage and load current .Assume VBE=0.5V and the zener operatesin the breakdown region. [6+4+6)

Figure 5

6. (a) Draw the Gain versus Frequency response of uncompensated and high fre-quency compensated CE wide band amplifier assuming that the lower 3-dBfrequency is zero.

(b) Explain High frequency compensation and what are the methods provided toachieve High frequency compensation in a CE amplifier? [8+8]

7. (a) What is square law distortion? what is its effect in FET amplifiers? Compareimportant characteristics of CD, CS, and CG FET amplifiers.

(b) A self biased CE amplifier circuit has RS = 10K, R1 = 100 K, R2 = 10 K, RC

= 5K, RE = 1K Find AI , AV , AV S and Ri. The h-parameters of the transistorare hfe = 50, hie = 1.1KΩ, hre = 2.5×10 - 4, hoe = 25 µA/V. Shown in figure7b.

2

Code No: 07A3EC14 R07 Set No. 2

Figure 7b

8. (a) Explain the significance of Low Pass Filter in Switching Regulator

(b) What are the limitations of Switching Regulators?

(c) Why switching frequencies are limited in Switching regulator and also explainhow to overcome this. [6+4+6]

? ? ? ? ?

3

Code No: 07A3EC14 R07 Set No. 4

II B.Tech I Semester Examinations,December 2011ELECTRONICS CIRCUIT ANALYSIS

Common to Electronics And Telematics, Electronics And CommunicationEngineering

Time: 3 hours Max Marks: 80Answer any FIVE Questions

All Questions carry equal marks? ? ? ? ?

1. (a) State Miller’s theorem. Explain its significance in transistor circuit analysis.

(b) For the amplifier shown in figure1b, calculateRi, Ro, AV , AV Sand A’I = - I2 / I1.The h-parameter values are hfe = 50, hie = 1.1KΩ, hre = 2.5x10 - 4, hoe = 24 µA/V.

Figure 1b

2. (a) Explain why voltage regulators are required for a DC power supply operatingfrom an AC source?

(b) If the DC output voltage is 600V with no load attached to power supply butdecreased to 400V at full-load find the percentage voltage regulation?

(c) For the circuit shown in figure2. If Vz=10V, β=100 and RL=100ohms. Findthe load voltage and load current .Assume VBE=0.5V and the zener operatesin the breakdown region. [6+4+6)

4

Code No: 07A3EC14 R07 Set No. 4

Figure 2

3. (a) What is square law distortion? what is its effect in FET amplifiers? Compareimportant characteristics of CD, CS, and CG FET amplifiers.

(b) A self biased CE amplifier circuit has RS = 10K, R1 = 100 K, R2 = 10 K, RC

= 5K, RE = 1K Find AI , AV , AV S and Ri. The h-parameters of the transistorare hfe = 50, hie = 1.1KΩ, hre = 2.5×10 - 4, hoe = 25 µA/V. Shown in figure3b.

Figure 3b

4. (a) Draw the Gain versus Frequency response of uncompensated and high fre-quency compensated CE wide band amplifier assuming that the lower 3-dBfrequency is zero.

(b) Explain High frequency compensation and what are the methods provided toachieve High frequency compensation in a CE amplifier? [8+8]

5. (a) Differentiate between a tuned voltage amplifier and a basic voltage amplifier.Draw the circuits of both of them. Also draw their frequency responses?

(b) Explain why tuned amplifiers cannot be used for amplification of low frequen-cies? [10+6]

6. (a) Derive various Resistive parameters of Hybrid - π model of a transistor interms of h parameters.

5

Code No: 07A3EC14 R07 Set No. 4

(b) What is the relationship between fT and fβ? Discuss the significance of fT .[12+4]

7. (a) Explain the significance of Low Pass Filter in Switching Regulator

(b) What are the limitations of Switching Regulators?

(c) Why switching frequencies are limited in Switching regulator and also explainhow to overcome this. [6+4+6]

8. (a) What are the advantages and disadvantages of push pull configuration? Showthat in Class-B push pull amplifier the maximum conversion efficiency is 78.5%

[8]

(b) A transistor in a transformer coupled (Class - A) power amplifier has to delivera maximum of 5 Watts to a load of 4Ω load. The quiescent point is adjusted forsymmetrical swing, and the collector supply voltage is VCC=20 Volts. AssumeVmin=0 volts.

i. What is the transformer turns ratio?

ii. What is the peak collector current? [8]

? ? ? ? ?

6

Code No: 07A3EC14 R07 Set No. 1

II B.Tech I Semester Examinations,December 2011ELECTRONICS CIRCUIT ANALYSIS

Common to Electronics And Telematics, Electronics And CommunicationEngineering

Time: 3 hours Max Marks: 80Answer any FIVE Questions

All Questions carry equal marks? ? ? ? ?

1. (a) Derive various Resistive parameters of Hybrid - π model of a transistor interms of h parameters.

(b) What is the relationship between fT and fβ? Discuss the significance of fT .[12+4]

2. (a) Draw the Gain versus Frequency response of uncompensated and high fre-quency compensated CE wide band amplifier assuming that the lower 3-dBfrequency is zero.

(b) Explain High frequency compensation and what are the methods provided toachieve High frequency compensation in a CE amplifier? [8+8]

3. (a) Explain why voltage regulators are required for a DC power supply operatingfrom an AC source?

(b) If the DC output voltage is 600V with no load attached to power supply butdecreased to 400V at full-load find the percentage voltage regulation?

(c) For the circuit shown in figure3. If Vz=10V, β=100 and RL=100ohms. Findthe load voltage and load current .Assume VBE=0.5V and the zener operatesin the breakdown region. [6+4+6)

Figure 3

4. (a) What are the advantages and disadvantages of push pull configuration? Showthat in Class-B push pull amplifier the maximum conversion efficiency is 78.5%

[8]

(b) A transistor in a transformer coupled (Class - A) power amplifier has to delivera maximum of 5 Watts to a load of 4Ω load. The quiescent point is adjusted forsymmetrical swing, and the collector supply voltage is VCC=20 Volts. AssumeVmin=0 volts.

7

Code No: 07A3EC14 R07 Set No. 1

i. What is the transformer turns ratio?

ii. What is the peak collector current? [8]

5. (a) What is square law distortion? what is its effect in FET amplifiers? Compareimportant characteristics of CD, CS, and CG FET amplifiers.

(b) A self biased CE amplifier circuit has RS = 10K, R1 = 100 K, R2 = 10 K, RC

= 5K, RE = 1K Find AI , AV , AV S and Ri. The h-parameters of the transistorare hfe = 50, hie = 1.1KΩ, hre = 2.5×10 - 4, hoe = 25 µA/V. Shown in figure5b.

Figure 5b

6. (a) Explain the significance of Low Pass Filter in Switching Regulator

(b) What are the limitations of Switching Regulators?

(c) Why switching frequencies are limited in Switching regulator and also explainhow to overcome this. [6+4+6]

7. (a) Differentiate between a tuned voltage amplifier and a basic voltage amplifier.Draw the circuits of both of them. Also draw their frequency responses?

(b) Explain why tuned amplifiers cannot be used for amplification of low frequen-cies? [10+6]

8. (a) State Miller’s theorem. Explain its significance in transistor circuit analysis.

(b) For the amplifier shown in figure8b, calculateRi, Ro, AV , AV Sand A’I = - I2 / I1.The h-parameter values are hfe = 50, hie = 1.1KΩ, hre = 2.5x10 - 4, hoe = 24 µA/V.

8

Code No: 07A3EC14 R07 Set No. 1

Figure 8b

? ? ? ? ?

9

Code No: 07A3EC14 R07 Set No. 3

II B.Tech I Semester Examinations,December 2011ELECTRONICS CIRCUIT ANALYSIS

Common to Electronics And Telematics, Electronics And CommunicationEngineering

Time: 3 hours Max Marks: 80Answer any FIVE Questions

All Questions carry equal marks? ? ? ? ?

1. (a) What is square law distortion? what is its effect in FET amplifiers? Compareimportant characteristics of CD, CS, and CG FET amplifiers.

(b) A self biased CE amplifier circuit has RS = 10K, R1 = 100 K, R2 = 10 K, RC

= 5K, RE = 1K Find AI , AV , AV S and Ri. The h-parameters of the transistorare hfe = 50, hie = 1.1KΩ, hre = 2.5×10 - 4, hoe = 25 µA/V. Shown in figure1b.

Figure 1b

2. (a) Explain why voltage regulators are required for a DC power supply operatingfrom an AC source?

(b) If the DC output voltage is 600V with no load attached to power supply butdecreased to 400V at full-load find the percentage voltage regulation?

(c) For the circuit shown in figure2. If Vz=10V, β=100 and RL=100ohms. Findthe load voltage and load current .Assume VBE=0.5V and the zener operatesin the breakdown region. [6+4+6)

10

Code No: 07A3EC14 R07 Set No. 3

Figure 2

3. (a) Differentiate between a tuned voltage amplifier and a basic voltage amplifier.Draw the circuits of both of them. Also draw their frequency responses?

(b) Explain why tuned amplifiers cannot be used for amplification of low frequen-cies? [10+6]

4. (a) Explain the significance of Low Pass Filter in Switching Regulator

(b) What are the limitations of Switching Regulators?

(c) Why switching frequencies are limited in Switching regulator and also explainhow to overcome this. [6+4+6]

5. (a) What are the advantages and disadvantages of push pull configuration? Showthat in Class-B push pull amplifier the maximum conversion efficiency is 78.5%

[8]

(b) A transistor in a transformer coupled (Class - A) power amplifier has to delivera maximum of 5 Watts to a load of 4Ω load. The quiescent point is adjusted forsymmetrical swing, and the collector supply voltage is VCC=20 Volts. AssumeVmin=0 volts.

i. What is the transformer turns ratio?

ii. What is the peak collector current? [8]

6. (a) State Miller’s theorem. Explain its significance in transistor circuit analysis.

(b) For the amplifier shown in figure6b, calculateRi, RI , AV , AV Sand A’I = - I2 / I1.The h-parameter values are hfe = 50, hie = 1.1KΩ, hre = 2.5x10 - 4, hoe = 24 µA/V.

11

Code No: 07A3EC14 R07 Set No. 3

Figure 6b

7. (a) Derive various Resistive parameters of Hybrid - π model of a transistor interms of h parameters.

(b) What is the relationship between fT and fβ? Discuss the significance of fT .[12+4]

8. (a) Draw the Gain versus Frequency response of uncompensated and high fre-quency compensated CE wide band amplifier assuming that the lower 3-dBfrequency is zero.

(b) Explain High frequency compensation and what are the methods provided toachieve High frequency compensation in a CE amplifier? [8+8]

? ? ? ? ?

12