EC6202- ELECTRONIC DEVICES AND CIRCUITS UNIT TEST-1 EXPECTED QUESTIONS 1. List the PN diode parameters. 1. Bulk Resistance. 2. Static Resistance/Junction Resistance (or) DC Forward Resistance 3. Dynamic Resistance (or) AC Forward Resistance 4. Reverse Resistance 5. Knee Voltage 6. Breakdown Voltage 7. Reverse Current (or) Leakage Current 2. Draw the V-I characteristics of a practical PN diode 3. Differentiate Between Drift And Diffusion Currents. Drift Current 1. It is developed due to potential gradient. 2.This phenomenon is found both in metals and semiconductors Diffusion Current 1.It is developed to charge concentration gradient. 2.It is found only in semiconductors. 4.What is an ideal diode? An ideal diode is one which offers zero resistance when forward biased and infinite resistance when reverse biased.
5. What is Reverse saturation current? The current due to the minority carriers in reverse bias is said to be reverse saturation current. This current is independent of the value of the reverse bias voltage. 6. Explain DC or Static Resistance The application of a dc voltage to a circuit containing a semiconductor diode will result in an operating point on the characteristic curve that will not change with time. The resistance of the diode at the operating point can be found simply by finding the Corresponding levels of V and I. 7. Explain AC or Dynamic Resistance Dynamic resistance of a diode can be defined as the ratio of change in voltage across the diode to the change in current through the diode. r = V / I Where r - Dynamic resistance of a diode V - change in voltage across the diode I - change in current through the diode 8. What are Semi Conductors?classification. Conductors which partially conduct are called as Semi Conductors. Eg. Germanium, Silicon. Classification: 1.Intrinsic Semi Conductors (Pure Type) 2. Extrinsic Semi Conductors (Impure Type) i. n-type ii. p-type 9. What is Rectification? The process of converting a sinusoidal AC waveform into a single polarity DC waveform is called Rectification. Rectification can be performed by 1. Half Wave Rectifier 2. Full Wave Rectifier 10.What are filters and its types Filters are those which reduce the ripples in the input voltage. Types 1. Shunt Capacitance 2. Series Inductance 3.LC Filter 4.π Filter 11.What are the types of breakdown in Zener Diode? The types of breakdown in Zener Diode are 1.Zener Breakdown 2.Avalanche Breakdown
12.What are the applications of Zener Diode? 1. Voltage Regulator 2. Peak Clippers 3. Wave Shaping 4. Meter Protection 13.What is a Voltage Regulator? A voltage Regulator is a circuit that makes the rectifier filter output voltage constant regardless of the variations in the input voltage or load. 14. Name some of the display Devices and explain the process of Electroluminence Display Devices 1.LED 2.LASER Diode Electroluminence When PN Diode is forward biased with GaAs, GaAsP, GaP as semiconductors charge carriers recombine and some of the energy is dissipated in the form of heat and light,if the semiconductor is translucent the light is emitted and the junction becomes a light source which forms Light Emitting Diode. This process is called Electroluminence. 15. LASER Diode Light Amplification by Stimulated Emission and Radiation. A laser emits radiation with a single wavelength or a very narrow band of wavelengths. This means that light has single colour (Monochromatic). 16. Diode Current Equation Where I -Diode Current IO-Diode Reverse Saturation Current V -ExternalVoltage η - Constant VT Thermal Voltage T -Temperature of the Diode 17. Draw the symbols of Junction and Zener Diode
18. What is barrier potential? The oppositely charged ions present on both sides of PN junction an electric potential is established across the junction even without any external voltage source which is termed as barrier potential. PART-B 1. Explain the Structure, Operation and VI Characteristics of Zener Diode 2. Explain the Structure, Operation and VI Characteristics of PN Junction Diode 3. Explain the Structure, Operation and Application of Light Emitting Diode 4. Briefly explain the Operation of Half Wave Rectifier 5. PN Diode as a Parallel Plate Capacitor 6. Zener Diode as Voltage Regulator, What are Filters and its types? 7. Briefly explain the Operation of Full Wave Rectifier 8. PN Diode as a Parallel Plate Capacitor
C.ABDUL HAKEEM COLLEGE OF ENGINEERING & TECHNOLOGY DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING Unit test- I EC6202- ELECTRONIC DEVICES AND CIRCUITS Year&SEM: II&III SET-A Maximum: 50 Marks Date: 22.07.2014 PART-A ANSWER ALL QUESTIONS (9 X 2 = 18 Marks) 1. What are Semi Conductors? Classification. 2. What are filters and its types? 3. What are the applications of Zener Diode? 4. Write the Diode Current Equation. 5. Short notes on LASER Diode. 6. Explain AC or Dynamic Resistance. 7. What is Reverse saturation current? 8. Draw the symbols of Junction and Zener Diode. 9. List the PN diode parameters. PART-B (2X16=32 Marks) 9. (a) Explain the Structure, Operation and VI Characteristics of PN Junction Diode(16) (b) Explain the Structure, Operation and Application of Laser Diode(16) 10. (a) Briefly explain the Operation of Full Wave Rectifier (16) (b) PN Diode as a Parallel Plate Capacitor (16)
C.ABDUL HAKEEM COLLEGE OF ENGINEERING & TECHNOLOGY DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING Unit test- I EC6202- ELECTRONIC DEVICES AND CIRCUITS Year&SEM: II&III SET-B Maximum: 50 Marks Date: 22.07.2014 PART-A ANSWER ALL QUESTIONS (9 X 2 = 18 Marks) 11. What is an ideal diode? 12. What is Rectification? 13. What are the types of breakdown in Zener Diode? 14. What is a Voltage Regulator? 15. Name some of the display Devices and explain the process of Electroluminence. 16. Explain DC or Static Resistance. 17. Differentiate Between Drift And Diffusion Currents. 18. Draw the V-I characteristics of a practical PN diode 19. What is barrier potential? PART-B (2X16=32 Marks) 20. (a).explain the Structure, Operation and VI Characteristics of Zener Diode(16) (b) Explain the Structure, Operation and Application of Light Emitting Diode(16) 21. (a) Briefly explain the Operation of Half Wave Rectifier (16) (b) i. Zener Diode as Voltage Regulator (8) ii. What are Filters and its types? (8) ------------ALL THE BEST----------