VLSIGURU INSTITUTE

WRITTEN TEST QUESTION ON BASIC ELECTRONICS

Note: Answer all the questions in shorter manner

1. Differentiate semiconductors, conductors and insulators on the basis of band gap?

2. Describe the difference between P-type and N-type semiconductor materials?

3. For the same order of doping, why does n-type semiconductor exhibit larger conductivity than p-type semiconductor?

4. Explain the operation of PN junction diode in Forward and reverse bias with I-V characteristics?

5. What is charge neutrality principle and explain why depletion region penetrates more into lightly doped region?

6. Why diode cannot be used as Amplifier?

7. Name the Types of BJT and Draw the Symbols for both the types and what are the different types of configurations present in the BJT?

8. Explain the significance of Emitter, Base, and Collector in the BJT and Compare the input resistance and output resistance of BJT in different configurations?

9. Explain the significance of Biasing in BJT?

10. Can a transistor be obtained by connecting two semiconductor diodes back-to-back?  What should be biasing of emitter base and collector base junctions for the different applications?

11. What is thermal runaway in BJT and how does it occurs?

12. What is base-width modulation in the BJT?

13. Draw the I-V characteristics of BJT in CE configuration and explain the region of operations?

14. How CE amplifier behaves for low frequency analysis and for high frequency analysis and for mid frequencies?

15. Define law of mass action and write the formula and why it is used? What is Einstein’s Equation in semiconductors and write the relation?

16. Name the capacitance present in the forward and reverse biased Diode?

17. What the parameters obtained from DC analysis of BJT or MOSFET and What are the parameters obtained from the AC analysis of BJT or MOSFET?

18. What is the difference between depletion type MOSFET and enhancement type MOSFET?

19. Explain the operation of NMOS enhancement mode MOSFET and Draw the cross-sectional view of NMOS enhancement mode transistor including bulk terminal?

20. Why MOSFET has Transfer characteristics instead of input characteristics? Draw the I-V characteristics of NMOS enhancement Mode MOSFET?

21. An N-channel enhancement MOSFET has threshold voltage = 0.7V and gate to source voltage = 1.5V. Find the region of operation if drain to source voltage is 2.5V?

22. Draw the circuit for CMOS inverter and write truth table Why PMOS is connected to VDD and NMOS is connected to ground in CMOS configuration?

23. Why PMOS aspect ratio is greater than NMOS in CMOS inverter?

24. What is difference between Gate oxide and Field oxide?

25. Explain the fabrication of NMOS transistor?

26. Why polysilicon is used instead of aluminium gate? What is Self-aligned gate technology explain briefly?

27. What is abbreviation of LOCOS and explain the steps? What is bird’s beak in LOCOS and what is technique to eliminate bird’s beak?

28. What is Latch UP and what are prevention techniques to overcome LATCH UP?

29. What is body effect and what are prevention techniques to overcome body effect?

30. What is difference between long channels and short channels? Define short channels and name the short channel effects?