Anna University
EC2151 ELECTRIC CIRCUITS AND ELECTRON DEVICES
QUESTION BANK
EC2151 ELECTRIC CIRCUITS AND ELECTRON DEVICES
QUESTION BANK
Semester : 2
Year : 1st Yr
Regulation : 2008 / 2010
Department : B.E CSE / ECE / B.Tech IT
UNIT I
PART . A
1. Define the following terms: i) Charge ii) Current iii) Voltage iv) Power
2. Define the following terms: i) Mesh ii) Loop iii) Node iv) Branch v)Network
3. Distinguish between a Branch and a node of a circuit.
4. Distinguish between a Mesh and a Loop of a circuit.
5. Define Active and Passive elements of the circuits.
6. Define Unilateral and Bilateral elements.
7. Define linear and Non-Linear elements.
8. Define Lumped and distributed elements
9. How is the electrical energy sources classified?
10. Define an ideal voltage and an ideal current source.
11. What are dependent and independent sources?
12. What are the different types of dependent or controlled sources?
13. What is resistance?
14. Write down the V- I relationship of passive circuit elements.
15. Define Ohm.s law.
16. State and explain Kirchhoff.s laws
17. Two resistances with the value of R1, R2 are connected in i) series and ii) parallel. What is the equivalent resistance?
18. Two inductors with the value of L1, L2 are connected in i) series and ii) parallel. What is the
equivalent inductance?
19. Two capacitors with the value of C1, C2 are connected in i) series and ii) parallel. What is the equivalent capacitance?
20. State voltage division rule.
21. State current division rule.
22. Define source transformation.
23. Write down the formula for a star connected network is converted into a delta network.
24. Write down the formula for a delta connected network is converted into a star network.
25. What is Mesh analysis?
26. What is Nodal analysis?
27. When do we go for super mesh analysis?
28. When do we go for super node analysis?
29. State superposition theorem.
30. State Thevenin.s theorem.
31. State Norton.s theorem.
32. State maximum power transfer theorem.
33. Define duality.
34. Write down few examples pf dual pairs.
PART - B
1. Explain voltage division & current division method using suitable example.
2. Derive the relationship to express three delta connected resistances into star.
3. Two resistances 15Ù and 20Ù are connected in parallel. A resistance of 12Ù is connected in series with the combination. A voltage of 120 V is applied across the entire circuit. Find the current in each resistance, voltage across 12Ù resistance and power consumed in all the resistances.
4. A resistance R is connected in series with a parallel circuit comprising two resistances of 12 and 8Ù.The total power dissipated in the circuit is 700 watts when the applied voltage is 200V. Calculate the value of R.
5. Explain the loop analysis of analyzing a given network, with a suitable example.
6. State and explain Superposition theorem.
7. State and explain Thevenin.s theorem.
8. A bridge network formed by four arms is as AB=2Ù, BC=3Ù, CD=4Ù, DA=5Ù. A 6 Ù resistance is connected between B and D. A battery source of 9V is connected with internal resistance of 1 Ù between A and C such that A is +ve and C is .ve. Calculate current through 6Ù resistance by, i) Norton.s theorem ii) Thevenin.s theorem.
UNIT II
PART A
1. What is transient state?
2. What is transient time?
3. What is natural response?
4. What is transient response?
5. Define Laplace Transform function.
6. What is Laplace transform of eat, sin at, teat and tn.
7. What is inverse Laplace Transform?
8. Define time constant of RL circuit.
9. Define time constant of RC circuit.
10. What is meant by natural frequency?
11. Define damping ratio.
12. Write down the condition, for the response of RLC series circuit to be under damped for step input.
13. Write down the condition, for the response of RLC series circuit to be over damped for step input.
14. Define initial value theorem.
15. Define final value theorem.
16. What is driving point impedance?
17. What is transfer point impedance?
18. Define network function.
19. Define Pole and zero.
20. Define resonant circuit.
21. When the circuit is said to be in resonance.
22. What is resonant frequency?
23. Define Bandwidth.
24. Define selectivity.
25. Define quality factor.
26. Define half power frequencies.
27. Write down the formula for inductive reactance and capacitive reactance.
28. Give the expression for quality factor of series RLC circuit.
29. Give the expression for quality factor of parallel RLC circuit.
PART . B
1. Determine the expression of resonant frequency and bandwidth of a series resonant circuit.
2. Derive the expression for the half power bandwidth of a parallel resonant circuit.
3. What is Q-factor? Find values of Q-factor for an inductor and capacitor.
4. In a single tuned resonant circuit, the applied voltage in a primary coil Eg = 20 volts (Rg=0), R1=R2=5Ù, L1=L2= 32 ìH, M =20ì H, secondary side capacitance C2 = 0.5ì F. Determine the resonant frequency and the output voltage at this frequency.
5. Derive the expression of maximum value of E0 and I0.
UNIT III
PART A
1. What is semiconductor?
2. What is energy level diagram?
3. What is energy band?
4. What are the classifications of semiconductors?
5. What is doping?
6. What are the classifications of extrinsic semiconductor?
7. What is N-type semiconductor?
8. What is P-type semiconductor?
9. Define mass Action Law?
10. List the semiconductor parameters which vary with temperature?
11. What is energy gap?
12. Define drift current.
13. Define diffusion current.
14. Write down the Einstein relationship equation?
15. Define diffusion length.
16. Define carrier life time.
17. What is continuity equation?
18. Define PN junction.
19. Write down the diode current equation.
20. What is static resistance?
21. What is dynamic resistance?
22. What is reverse resistance?
23. Define transition capacitance.
24. Define diffusion capacitance.
25. What are the breakdowns in PN junction diode?
26. What is zener diode?
27. What are the breakdown mechanisms in zener diode?
28. What are the applications of zener diodes?
PART . B
1. Explain the PN junction diode.
2. Explain the diode current equation.
3. What are the PN diode applications?
4. Derive the expression for transition capacitance and diffusing capacitance.
5. Explain different methods of breakdown in PN junction diodes.
6. Describe the operation of Zener diode and explain its characteristics.
UNIT . IV
PART . A
1. What is Transistor?
2. What are the advantages of Transistor?
3. What are the types of Transistor?
4. Describe the basic structure of the BJT?
5. What are the three terminals in a BJT?
6. What is biasing?
7. What are the types of transistor configuration?
8. Define static characteristics curves in CB configuration.
9. Define input characteristics for CB configuration.
10. What is early effect?
11. What is meant by punch through?
12. Write the current amplification factor for a CB transistor.
13. Write the current amplification factor for a CE transistor
14. Write the current amplification factor for a CC transistor.
15. Write the formula for input resistance in a CB transistor.
16. Define output characteristics for CB configuration.
17. Write the relationship between á and â.
18. Which is the most commonly used transistor configuration? Why?
19. Why is silicon preferred over germanium in the manufacture of semiconductor devices?
20. What are the different types of transistor breakdown?
21. Define delay time.
22. Define rise time.
23. Define turn-on time.
24. Define storage time.
25. Define fall time
26. Define turn off time.
27. Give few reasons for storage time.
28. What are the types of FET?
29. Define pinch off region.
30. Define characteristic curve.
31. List the characteristics of JFET.
32. Define pinch off voltage.
33. Write down Shcotkly.s equation.
34. Which is the normal operation region in JFET?
35. What is break down voltage?
36. List the characteristic parameters of JFET.
37. Define Transconductance.
38. Define Drain resistance.
39. Define Drain conductance.
40. Define amplification factor.
41. What is MOSFET?
42. What are the types of MOSFET?
43. What is the other name for MOSFET?
44. What are the precautions to be taken when handling MOSFET?
45. Write the use of JFET as a voltage variable resistor.
PART - B
1. Compare transistor configurations.
2. Explain about Avalanche multiplication.
3. Explain about Reach through or Punch through.
4. Give some reasons for delay time.
5. Give some reasons for rise time and fall time.
6. Describe the transistor switching times.
7. What are the features of FET?
8. Explain the Characteristics of JFET with the help of neat sketches.
9. With the help of suitable diagrams explain the working of different types of MOSFET.
10. Compare FET and BJT.
11. What are the applications of JFET?
12. Compare JFET and MOSFET.
13. Compare N-channel and P-channel MOSFETs.
14. Compare N-channel and P-channel FETs.
UNIT V
PART - A
1. What is Varacter diode?
2. What are the applications of Varacter diode?
3. What is tunneling?
4. What are the applications of Tunnel diode?
5. What is Photo diode?
6. What are the types of display devices?
7. What is active display device?
8. What is passive display device?
9. What are the types of LED?
10. What are the advantages of LED?
11. What are the types of LCD.s?
12. What are the applications of LCD?
13. Describe the basic structure of SCR.
14. What is forward break over voltage?
15. What is reverse break over voltage?
16. Define holding current.
17. What is the forward blocking region?
18. Define Latching?
19. What are the turn OFF mechanism used for SCR?
20. What are the advantages of SCR?
21. What is latching current?
22. What is holding current?
23. Define voltage safe factor.
24. What is turn ON time?
25. What is turn OFF time?
26. What is LASER?
27. Give the applications of LASER.
28. What is TRIAC?
29. What are the applications of TRIAC?
30. What is DIAC?
31. What are the applications of DIAC?
32. What is UJT?
33. What is intrinsic stand OFF ratio of UJT?
34. What is peak point voltage?
35. What are the applications of UJT?
36. Explain the following terms: i) Photoconductive sensor ii) Photo emissive sensor
PART - B
1. Explain the operation of PIN diode.
2. Compare Tunnel diode and P-N junction diode?
3. What are the applications of PIN diode?
4. Describe the operation of LED and LCD.
5. Explain the operation of TRIAC and DIAC.
6. Draw the equivalent circuit of UJT and explain its operation.
7. What are the different regions in characteristic of UJT?
8. Write short notes on light activated SCR.
9. Compare SCR and TRIAC?
10. What are the different operating modes of TRIAC?
11. Compare LCD and LED.
12. What are the applications of LED?
13. Give the applications of SCR.
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