RAJIV GANDHI COLLEGE OF ENGINEERING AND TECHNOLOGY

Transcription

1 RAJIV GANDHI COLLEGE OF ENGINEERING AND TECHNOLOGY DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING QUESTION BANK EE T34 - Electronic Devices and Circuits II YEAR / III SEMESTER RGCET 1

2 UNIT-I 1. How does the avalanche breakdown voltage vary with temperature? 2. What are semiconductors? 3. Draw the V-I characteristics of a diode 4. What is meant by extrinsic semiconductor? 5. Draw the equivalent circuit of diode. 6. Distinguish between avalanche and zener break down. 7. A silicon diode has a saturation current of 7.5µA at room temperature 300 K. Calculate the saturation current at 400 K. 8. Write the difference between avalanche and zener break down. 9. What is meant by static forward resistance? 10. Distinguish between intrinsic and extrinsic semiconductors. 11. Draw the energy band structure of semiconductor. 12. What is the effect of temperature on diode operation. 13. What is Hall Effect? 14. What is the significance of transition capacitance? 15. Define drift current for a semiconductor. 16. What is meant by diffusion current in a semiconductor? 17. Calculate the speed of electron when it falls by potential of 300 k volts. PART-B 1. Draw and explain the operation and characteristics of a PN junction diode. Also derive its current equation. 2. Write short note on the following. (i) Diode switching time (ii) Transition and diffusion capacitance. 3. Explain the behavior of PN junction diode in forward bias and reverse bias mode. Discuss the effect of temperature on the volt-ampere characteristic of a diode? 4. (a) Draw the VI characteristic of PN junction diode. Explain its principle of operation. (b) The reverse saturation current of a silicon PN junction diode is 10µA. Calculate the diode current for the forward bias voltage of 0.6V at 25 C. RGCET 2

3 5. Distinguish between space charge capacitance and diffusion capacitance in all aspects. 6. Derive the expression for the transition capacitance and diffusion capacitance of a diode. 7. Explain the operation of a PN junction diode under forward and reverse biased condition. Also explain the characteristic of a PN-junction diode. UNIT-II 1. Why an ordinary transistor is called bipolar? 2. Among CE, CB, CC which one is most popular. Why? 3. Draw the symbol of PNP and NPN transistor. 4. What is emitter bias? 5. Define thermal runaway. 6. What is thermal stability? 7. What is meant by transistor? 8. Draw the h-parameter equivalent circuit of a CE BJT configuration? 9. Define the term current amplification factor in common collector transistor. 10. What is reverse saturation current? 11. What is meant by biasing and the need of biasing? 12. How the compensation is achieved in diode compensation for V BE? 13. What is DC load line? 14. What is meant by Q-point? 15. Mention the two factors affecting the stability of a Q point. 16. What is stability factor? 17. What are the requirements for biasing a circuit? 18. Define three stability factor. 19. What is early effect? PART-B 1. a) Explain why CE configuration is popular in amplifier circuits? b) Compare all the three configurations of a BJT in terms of their circuit parameters. RGCET 3

4 2. Draw the circuit diagram of a common base NPN transistor circuit and explain the input and output characteristics of common base connection. 3. Explain the operation of NPN and PNP transistor. 4. Explain the principle of transistor action in CE configuration. Also discuss in detail its input and output characteristics. 5. Explain Eber-moll model in detail. 6. Draw the circuit diagram of collector-base bias circuit using CE configuration and explain how it stabilizes operating point. 7. Explain briefly about the various types of BJT biasing. 8. Explain the bias compensation techniques using diode and thermistor. 9. Draw the self-bias BJT networks. Derive expression for ICQ and VCEQ and describe the mention of drawing the dc load line on the output characteristics. 10. Explain in detail about different types of bias compensation techniques to compensate for variations in current. UNIT-III 1. Distinguish DMOSFET and EMOSFET. 2. What is the difference between a JFET and a bipolar transistor? 3. What is MOSFET? How many types of MOSFET are there? 4. Give any two application of JFET? 5. What is dual mode MOSFET? 6. Draw the drain characteristics of p-channel enhancement MOSFET? 7. What do you understand by pinch off voltage? 8. What are the different operating regions of JFET? 9. MOSFET is also called as IGFET. Justify. 10. Draw the high frequency model of JFET. 11. List the name of regions in the VI characteristics of UJT. 12. Why FET is called voltage control device? RGCET 4

5 PART-B 1. Explain the operation and VI characteristics of JFET. 2. Explain the construction and operation of E-MOSFET 3. Explain the construction and operation of N-channel JFET. Discuss its characteristics. 4. Explain the construction and working of n-channel J-FET. 5. Draw and explain the biasing circuits for MOSFET using common source configuration. 6. Explain voltage divider bias and self-bias of J-FET in detail. 7. Explain DC load line and Q-point of a transistor in detail. UNIT-IV 1. Define the term threshold voltage 2. What is a DIAC? Give the basic construction and symbol of DIAC. 3. Mention the application of UJT. 4. Define the holding current in SCR. 5. Draw the VI characteristics of TRIAC. 6. Draw the typical VI characteristics of UJT? 7. Why is Zener diode used as a voltage reulator? 8. Define breakdown voltage of SCR 9. What is intrinsic standoff ratio of UJT? 10. What are the basic rectifier circuits? 11. Is the capacitor filter suitable for heavy loads? Justify the reason. 12. What are the factors affecting the output voltage of a regulated power supply? 13. Define the term ripple factor? 14. What is the advantage of switching regulator? 15. What is the need for current limiting circuit? 16. Mention the function of switching regulators. 17. What is meant by fold back limiting in a voltage regulator? 18. What is meant by switching regulator? RGCET 5

6 PART-B 1. What is SCR? Explain construction, operation and its VI characteristics. 2. Explain the working of SCR. Draw its forward and reverse characteristics. 3. Explain the construction and characteristics of SCR. 4. Explain with the help of a circuit diagram the working of UJT. Mention some of the applications of UJT. 5. Explain the construction and working of SCR and UJT with necessary diagram. 6. Describe principle of working of GTO. 7. With a neat diagram, explain the following. (a) Shunt transistorized voltage regulators (b) Series voltage regulator 8. Explain the action of the following filter circuits used in a power supply (a) LC filter (b) CLC filter 9. With the help of circuit diagram, explain the function of OP-AMP voltage regulator. 10. Derive the expression of the ripple factor for the following filters C, L, LC, and CLC. Full wave rectified signal is applied as input. 11. Explain full wave rectifier and derive its ripple factor for C and LC filters. UNIT-V 1. What is optocoupler? 2. What are the applications of photo diode? 3. How does LED differ from an ordinary diode? 4. What is tunneling? 5. What are the applications of PIN diode? 6. Give the principle of operation of solar cell. 7. Why is photo diode used in reverse biased condition? Give reasons. 8. Give the symbol and structure of schottky diode. 9. What is zener breakdown. 10. Draw the characteristics of varactor diode. 11. Write any four applications of varactor diode? RGCET 6

7 12. Draw the small signal equivalent circuit of a tunnel diode. 13. List the applications of PIN diode. 14. How does the width of depletion layer change the capacitance of a varactor? PART-B 1. Discuss the following in brief (a) Tunnel diode (b) Phototransistor (c) Solar cell 2. Explain the construction and working of schottky diode. Give its applications. 3. What is zener diode? Explain how zener diode acts as a voltage regulator. 4. What is a zener diode? Explain the reverse characteristic of a zener diode? 5. Explain the Tunneling phenomenon in a Tunnel diode with transfer characteristics curves and state the advantages. 6. Write short notes on (a) Tunnel Diode (b) PIN diode. 7. Describe the construction and operational characteristics of LED. Mention its merits and demerits. 8. Explain the principle of operation and characteristics of Liquid Crystal Displays. RGCET 7