EC2151 ELECTRIC CIRCUITS AND ELECTRON DEVICES ANNA UNIVERSITY PREVIOUS YEAR QUESTION PAPER, IMPORTANT QUESTIONS, 2 MARKS AND 16 MARKS QUESTIONS FOR ECE DEPARTMENT

ELECTRIC CIRCUITS AND ELECTRON DEVICES ANNA UNIVERSITY PREVIOUS YEAR QUESTION PAPER, IMPORTANT QUESTIONS, 2 MARKS AND 16 MARKS QUESTIONS FOR ECE DEPARTMENT

ANNA UNIVERSITY PREVIOUS YEAR QUESTION PAPER EC2151 ELECTRIC CIRCUITS AND ELECTRON DEVICES , IMPORTANT QUESTIONS, 2 MARKS AND 16 MARKS QUESTIONS FOR ECE DEPARTMENT

B.E./B.Tech. DEGREE EXAMINATION, JUNE 2010

Second Semester

Computer Science and Engineering

EC2151 – ELECTRIC CIRCUITS AND ELECTRON DEVICES

(Regulation 2008)

(Common to Biomedical Engineering, Electronics and Communication Engineering

and Information Technology)

Time : Three hours Maximum : 100 Marks

Answer ALL Questions

PART A — (10 × 2 = 20 Marks)

1. State Kirchoff’s current law and voltage law.
2. State Superposition theorem.
3. What is quality factor?
4. Find the resonant frequency in the ideal parallel LC circuit shown in Fig.1
Fig.1.
5. Give the expression for transition capacitance and diffusion capacitance of a
PN diode.
6. Define avalanche break down?
7. What is “Early effect” in CB configuration and give its consequences?
8. Distinguish clearly the difference between N with P channel FETs.
9. Give some applications of tunnel diode.
10. What is meant by photovoltaic cell?

PART B — (5 × 16 = 80 Marks)

11. (a) (i) State Thevenin’s and superposition theorems, mention one
application. (8)
(ii) Find the Thevenin’s equivalent of the circuit shown in Fig. 2. (8)
Fig.2
Or
(b) (i) Consider the circuit in Fig. 3. (12)
Fig. 3
(1) If Rout = 3 k , find the power delivered to it.
(2) What is the maximum power that can be delivered to any Rout?
(3) What two different values of Rout will have exactly 20mw
delivered to them?
(ii) State maximum power transfer theorem. (4)
12. (a) In the circuit shown in Fig. 4, determine the complete solution for the
current when the switch is closed at t = 0. Applied voltage is
) 4 / 500 cos( 400 v(t) π + = t , resistance R = 15 , inductance H L 2 . 0 =
and capacitance F C µ 3 = . (16)
Fig. 4
Or
 132  132  132 
E 3070 3
(b) (i) Explain (using the relevant circuit) the double tuned circuit and
derive the expression for A and Mc. (10)
(ii) The tuned frequency of a double tuned circuit shown in Fig.5 is
104 rad/sec. If the source voltage is 2 v and has a resistance of
0.1 , calculate the maximum output voltage at resonance if
= 01 . 0 1
R , H L µ 2 1 = , = 1 . 0 2
R and H L µ 25 2 = . (6)
Fig. 5
13. (a) (i) Derive the PN diode current equation. (8)
(ii) Explain how the depletion region at a p-n junction is formed and
explain with relevant sketches for charge density, electric field
intensity and potential energy barriers at the junction. (8)
Or
(b) (i) Draw the Zener diode characteristics and explain the working of
Zener diode. (8)
(ii) Draw the Zener regulation circuit and explain its function for input
regulation and output regulation. (8)
14. (a) Explain the input and output characteristics of a common emitter
configuration with a neat sketch. (16)
Or
(b) What is MOSFET? Explain the construction and working principle of
enhancement mode and depletion mode MOSFET with a neat diagram.
(16)
15. (a) What is tunneling phenomenon? Describe the V-I characteristics and
concepts of tunnel diode with application. (16)
Or
(b) Explain the negative resistance characteristics of Unijunction Transistor
with neat sketch. (16)