Cochin University of Science and Techology (CUST) 2007-1st Year B.Tech elecrical and electronics engineering - Question Paper

BTECH DEGREE MODEL exam APRIL 2007
BASIC ELECTRICAL ENGINEERING & ELECTRONICS
Time:3 Hrs Max marks: 100


ELECTRICAL

PART A

1. a) State and discuss Kirchoff’s legal regulations.

b) describe RMS, avg. and peak value of ac. What is form factor?

c) State and discuss Faraday’s legal regulations.

d) State and discuss Coulomb’s legal regulations.

e) How can we convert a galvanometer to ammeter?

PART B

2. a) State and discuss super position theorem.

b) provide a suitable numerical example for super position theorem

3. a) describe 1) capacitance 2) charge 3) potential. Derive an formula b/w them.

b) Capacitors 4.2 micro Farad and 2.8 micro Farad are connected in series with a different
capacitor. The effective capacitance is 0.9 micro Farad. If the group is connected
across 500V dc, compute 1) capacitance of 3rd capacitor 2) charge 3) voltage
across every capacitor.

c) discuss Norton’s theorem and derive the formula.

PART C

4. a) discuss self induction and mutual induction.

b) discuss the working principle of energy meter.

c) Show that line to line voltage of a three phase system is 1.732 times Vph. Draw the
voltage phasor diagram for ABC sequence.
OR
5. a) An inductor of 20 ohm resistance and 0.1 H inductance is connected in series with a
non inductive resistor 50 ohm. They are supplied from 230V 50Hz. obtain the current
voltage and power factor of the circuit.

b) Resistance of 20 ohm, inductance of 0.2 H and capacitance of 100 micro Farad is
connected in series across 220V 50Hz mains. Determine 1) Impedance 2) current
3) voltage across R, L & C 4) Power in Watts and VA 5) power factor angle of lag.

ELECTRONICS

PART D

6. a) Differentiate b/w avalanche and zener breakdown.

b) discuss the term modulation and need for it in communication.

c) What is a transducer? elaborate various classes of transducer?

d) What is rectification? elaborate the various kinds of rectification?

e) elaborate Lissajeous pattern? How they are used in phase measurement.

PART E

7. a) Draw the block diagram of CRO & discuss every block briefly.

b) Compare performance of AM & FM.
OR

8. a) Write the method to measure pressure, velocity, vibration & temperature .

b) What is demodulation? Draw & discuss the ckt for AM reception.

PART F

9. a) Draw the V-I characteristics of Zener diode.

b) What is ripple factor& how can it decrease.

c) Distinguish b/w electron& hole.

OR
10.a) discuss the working of FET .

b) discuss the operation of npn transistor.

c) Draw the characteristics of UJT & discuss it.

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Earning:   Approval pending.