B.Tech-ELECTRONICS AND COMMUNICATIONS 1st Sem ELECTRICAL TECHNOLOGY(Maharashi Dayanand University (MDU), Rohtak-2009)

NOTE: attempt any five question.

1. (a) State kirchoff's laws of current and voltage. 3
(b) State maximum power transfer theorem. 3
(c) What are crest and peak factor ? 3
(d) What are unbalanced circuits ? 3
(e) What are eddy currents ? 3
(f) What are cut-off frequences ? 3
(g) Explain , what is slip ? 3

2.(a) Derive expression for converting delta circuits to star circuits. 10
(b) Differentiate between: 10
(1) lumped parameter and distributed parameters,
(2) mesh and loop,
(3) active and passive components and sources.

3. (a) State and explain thevenin's theorem. 10
(b) State and explain milbman's theorem. 10

4. (a) Explain the behaviour of R - C circuits to step response. 10
(b) Explain the concept of voltage and current in RL ,RC and RLC circuits with the help of phasor diagrams. 10


5.(a) Derive results of resonant frequency , bandwidth and impedence un case of series RLC circuits.
10
(b) Derive relation between lc and lph, vc and vph in case of star connected three phase circuits.
10


6. (a)Explain how three phase power can be measured by two wattmeter method? 10
(b) Draw and explain the construction of transformer and derive emf equation. 10


7. (a) Explain how S.C test is performed and why ? 10
(b) Draw and explain the phasor diagram of transformer with no load and full load. 10


8. (a) Explain the construcction and working of synchronous motor. 10
(b) Explain the working principle of D.C machine and derive emf. equation for it . 10

9. Write short note on :
(a) Induction type voltmeter, 10
(b) Energy Meter. 10

Earning:  ₹ 4.00/-