ELECTRICAL AND ELECTRONICS ENGINEERING-SUPPLY 2K4

Code No: RR-12302
I B.Tech. Supplementary Examinations, Nov/Dec-2004
ELECTRICAL AND ELECTRONICS ENGINEERING
(Bio-Technology)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
- - -
1.a) With a neat sketch explain the construction and principle of operation of
dynamometer type watt meter.
b) Two 40w tube lights are ON for a period of six hours a day. Calculate the total
energy consumed by them in a month?
2.a) Discuss the torque – armature current characteristics of various types of d.c
motors and give the practical applications of each type of motor.
b) Discuss classification of d.c motors with suitable diagrams.
3.a) Give the electronics configurations of Silicon and Germanium.
b) What is the difference between intrinsic and extrinsic semi-conductors.
c) Draw energy band diagrams of (i) Insulator (ii) Semiconductor and
(iii) Metal, and hence explain the difference in their conductivities.
4.a) Draw the circuit diagram of half wave rectifier and explain its operation.
b) A half wave rectifier is fed by 220V, 50Hz via a step down transformer of turns
ratio 11:1 find i) the output d.c. and ii) peak inverse voltage under no load
condition.
5.a) Draw the emitter characteristic of UJT and explain the shape of the curve
qualitatively. Mention different regions of operations.
b) Draw the circuit of a relaxation oscillator and explain its operations. Mention it’s
applications.
6.a) Draw the circuit of a transformer coupled amplifier and explain its operations.
b) Draw the circuit of a class B push-pull amplifier and derive expression for the
output power.
7.a) Discuss and explain the basic circuit of an LC oscillator and derive the condition
for the oscillations.
b) Compare various multivibrators.
8.a) Show that the dual of the exclusive-OR in equal to its complement.
b) Design a synchronous counter with the binary. Sequence: 0, 1, 2, 3 and repeat use
RS flipflops.
c) Show that a positive-logic AND gate is a negative-logic OR gate.
*$*$*$*
Set No.
1
Code No: RR-12302
I B.Tech. Supplementary Examinations, Nov/Dec-2004
ELECTRICAL AND ELECTRONICS ENGINEERING
(Bio -Technology)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
- - -
1.a) Derive the voltage current relations (between line and phase) values for a
star – and – delta connected systems.
b) A 3-phase, 4 wire 208V system supplies power to a star connected load each arm
with impedance equal to (17.32 – J10) ohms (per phase) find the line currents,
power consumed, and the power factor of the load.
2.a) Describe the construction of a 1-phase transformer and principle of operation.
b) Write about 3-phase transformer connections.
3.a) Explain how a P-type semiconductor is formed. What are the different impurities
used for this process.
b) Derive the expression for intrinsic conductivity.
c) Explain about charge densities in a semiconductor.
4.a) What do you mean by regulation and explain how a full wave rectifier is used for
it.
b) Compare center tapped transformer and ordinary transformer. What is the
difference in their construction?
c) Mention the applications of Rectifiers in detail.
5.a) Compare and contrast of FET and BJT.
b) Give the constructional features of JFET and explain its operation with the help of
the drain characteristics.
c) From the drain characteristics derive mutual characteristic and explain the shape
of the curve qualitatively.
6.a) Draw the circuit of a current shunt feedback amplifier and explain.
b) An amplifier has a gain of 10,000 without feedback. The gain is reduced to 50
with negative feedback. Find the feedback factor.
c) Explain the principle of operations of Tuned amplifiers.
7.a) Distinguish between symmetrical and asymmetrical triggering methods in
multivibrators.
b) Explain the operation of bistable multivibrator circuit with base and collector
waveforms.
Contd…2
Set No.
2
Code No: RR-12302 -2- Set No-2
8.a) Explain the working principle of a 4-bit binary up and down counter with its truth
table.
b) Show that a negative-logic AND gate is a positive-logic OR gate.
c) Distinguish between edge-triggering and level triggering.
*$*$*$*
Code No: RR-12302
I B.Tech. Supplementary Examinations, Nov/Dec-2004
ELECTRICAL AND ELECTRONICS ENGINEERING
(Bio-Technology)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
- - -
1.a) Derive an equation for the total power consumed in a three – phase circuit.
Will it depend on the type of load connected?
b) Three identical impedances 10Ð53.10 ohm [10 (cos(53.1)0 + Jsin(53)0] are
connected in delta to a 3-phase, 240volt balanced supply. Find the line currents
and power consumed.
2.a) Discuss the construction of various types of 3-phase induction motor.
b) Explain the terms (i) Synchronous speed (ii) slip
c) A 4-pole 3-phase induction motor operates from 440V, 3-phase 50 HZ supply.
and runs at a speed of 1440 r.p.m What are the values of synchronous speed,
slip speed and percentage slip.
3.a) Explain the Law of junction for p-n diode.
b) Explain Avalanche and Zener break downs and compare.
c) Derive Diode current equation.
4.a) Explain the specifications and applications of DIAC, TRIAC and SCR.
b) Compare and contrast the construction and characteristic features of DIAC and
TRIAC.
5.a) Sketch a family of drain characteristics of JFET and explain the shape of the
curves qualitatively.
b) Obtain transfer characteristic of JFET from its drain characteristics and explain
the shape of curves qualitatively.
c) How a JFET can be used as voltage variable resistor (VVR)? Explain.
6. Derive the expression for input and output resistances of voltage series and
current shunt feedback amplifiers.
7.a) Explain the working principle of Colpitt’s oscillator and derive the formula for the
O/P signal frequency.
b) Explain the operation of one-shot circuit with relevant waveforms.
8.a) Verify the truth table for the 3-input exclusive OR gate. List a1l 8 combinations
of x, y, and z. Evaluate A = x Å y Å z.
b) Show the logic diagram of a clocked D flipflop with AND and OR gates, explain
it.
c) Explain the principle of clocked RS-flipflop with its logic diagram.
*$*$*$*
Set No.
3
Code No: RR-12302
I B.Tech. Supplementary Examinations, Nov/Dec-2004
ELECTRICAL AND ELECTRONICS ENGINEERING
(Bio Technology)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
- - -
1.a) Explain the production of 3-phase voltages.
b) Derive relation between phase and line values of voltages and currents of star
and delta connected systems.
c) A 3-phase star connected load draws a current of 10Ð300 per phase from a
3- phase, 440V, supply. Calculate the line current.
2.a) Give the various power stages of a 3-phase induction motor the various stages
from the input to induction motor to output) and explain each stage.
b) Explain principle of operation of three – phase induction motor.
3.a) Draw the V-I characteristics of Zener diode and explain.
b) For the Zener voltage regulator shown below determine range of RL and IL that
gives a stabilized voltage of 10V. What should be wattage rating of the diode.
c) Explain how Zener diode acts and voltage regulator.
4.a) Explain with neat circuit diagram how SCR can be used as HWR.
b) Explain how SCR can be used as a switch.
c) Explain the turn on mechanism of SCR.
5.a) Explain qualitatively the three consequences of base-width modulation.
b) Sketch a family of CE input, output characteristics for the given npn BJT and
explain shape of the curves qualitatively.
c) How a transistor circuit acts as a switch. Explain with suitable example.
6.a) Compare the four feedback amplifier configurations with reference to the gain
Bandwidth, Rif and Rof.
b) Derive the expression for Avf, Rif, Rof and Ro’f of an emitter folower circuit.
7.a) Explain the principle of operation of self-bias binary circuit.
b) A FET phase shift oscillator has gm=500ms, and rd = 30kW. The feedback
resistance is 100kW, and the capacitor value is 64.97pF. Calculate the frequency
of oscillations and the value of RD. Draw the corresponding circuit diagram.
8.a) Construct a 4-bit left shift register using D-flipflops and explain its operation with
reference to clock.
b) Draw the logic diagrams for D-flipflop and T-flipflop and explain their working
with truth table.
c) Explain the working of decade counter and realize it using T-flipflops.
*$*$*$*