Periyar University 2006 B.Sc Electronics COMPONENTS AND CIRCUIT ANALYSIS - Question Paper

Second Semester
Electronics
COMPONENTS AND CIRCUIT ANALYSIS
Time : 3 hours Maximum : 100 marks
part A — (10 x two = 20 marks) ans ALL ques..
All ques. carry equal marks.

1. 2 resistors are stated to be connected in series if
(a) both carry the identical value of current
(b) total current equals the sum of branch currents
(c) sum of IR drops equals the applied emf
(d) same current passes in turn through both.

2. The capacitor and inductor will vary their
reactance with respect to the of the
applied AC.
3. The algebraic sign of an IR drop in a closed loop is
primarily dependent upon the
(a) amount of current flowing through it
(b) value of R
(c) direction of current flow
(d) battery connections.

4. In Thevenine to Norton conversion the IN (Norton's Current) and RN (Norton's Resistance) are found by IN = ? and RN = ?. (the formulae).
5. Electric power is almost exclusively generated transmitted and distributed by 3 phase system because

(a) it is more efficient
(b) it uses less material for a provided capacity
(c) it costs less than single phase system
(d) all the above.
6. The power factor of an ac circuit is provided by
(a) cosine of the phase angle
(b) tangent of the phase angle
(c) the ratio RIXL
(d) the ratio XLIZ .
7. The voltage applied across an R-L circuit is equal
to — of VR and VL
(a) arithmetic sum
(b) algebraic sum
(c) phasor sum
(d) sum of the squares.
8. Higher value of the Q in a series circuit
(a) greater its bandwidth
(b) sharper its resonance
(c) broader its resonance curve
(d) narrow its passband.
9. The power taken by a 3-0 load is provided by
10. The components, due to which the transient currents generated are and .
part B — (5 x six = 30 marks)
ans ALL ques..
11. (a) discuss the construction of an electrolytic
capacitor with neat diagram.
Or
(b) compute the value of the resistors which when connected in series provide 50 Q., and eight Q. when they are in parallel.
12. (a) elaborate the sequential steps involved in
Nortonising a complex circuit?
Or
(b) How Millman's theorem is useful in solving the circuit? discuss.
13. (a) elaborate phasor-diagrams? Draw a phasor
diagram for a single phase AC and discuss.
Or
(b) Write short note on 2 port networks. Bring out their significances.
14. (a) Derive an expression to compute the energy
stored in a capacitor.
Or
(b) In a series R.C. circuit explain the voltage and impedance triangles (vector diagrams).
15. (a) How will you measure the power in a
3-phase load using 3 wattmeters? discuss.
Or
(b) find the transient current in an Rr-C series circuit with DC-exitation.
part C — (5 x 10 = 50 marks)
ans ALL the ques..
16. (a) Narrate the various kinds of capacitors and
their specific uses.
Or
(b) What is self inductance and mutual inductances discuss them in detail? Bring out the kinds of inductors and their uses.
17. (a) How will you Thevenise a bridge network?
discuss with suitable example. Convert the found
circuit into Norton's circuit.
Or
(b) Determine the branch currents in the network provided beneath. When the value of every resistance in 1 ohm. (ref book no 38)
18. (a) An alternating current varying sinusoidally
with a frequency of 50 Hz has an RMS value of 20 A
write down the formula for the instantaneous value
and obtain this value (i) 0.0025 sec (ii) 0.0125 sec after
passing through a positive maximum value. At what
time, measured from the positive maximum value, will
the instantaneous current be 14.14 A.
Or
(b) find the expression for the instantaneous value of AC and write down the 3-phase expressions separately.
19. (a) define the behaviour of a series AC circuit
with resistance and inductance. Derive various power
expression and explain.
Or
(b) describe Q-factor of a coil, and discuss the Q-factor of a series RLC circuit, and parallel circuit.
20. (a) Narrate the 2 wattmeter method for measuring the power in a 3-phase system, for various loads, (balanced or unbalanced loads).
Or
(b) Prove that in a RL circuit with DC excitation
the transient current i. = V / R e –t / ?

Earning:   Approval pending.