code no: r22026 r10 set - 1 ii b. tech ii semester ... no: r22026 ii b. tech ii semester...

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Code No: R22026

II B. Tech II Semester Supplementary Examinations Jan/Feb - 2015

CONTROL SYSTEMS (Com. to EEE, ECE, EIE, ECC, AE)

Time: 3 hours Max. Marks: 75

Answer any FIVE Questions All Questions carry Equal Marks

~~~~~~~~~~~~~~~~~~~~~~~~

Note: Provide ordinary and Semi log graph sheets

1. a) Why negative feedback is preferred in control systems? What are the characteristics of

negative feedback?

b) Explain the effects of feedback on i) stability ii) sensitivity iii) External disturbance

(6M+9M)

2. a) Explain how a two phase servomotor differs from a normal induction motor.

b) Reduce the given block diagram (figure 1) and hence obtain the transfer function ( )

.( )

C s

R s

c) Compare ac and dc servomotors. (3M+8M+4M)

3. a) Define the test signals i) Step ii) Parabolic iii) Impulse

b) What is the effect of derivative control on damping ratio, peak overshoot, steady state error

and rise time.

c) Consider the closed-loop system given by .2)(

)(22

2

nn

n

sssR

sC

ωξω

ω

++= Determine the values of

ξ and so that the system responds to a step input with approximately 5% overshoot and

with a setting time of 2 sec. (Use the 2% criterion). (3M+4M+8M)

4. a) Explain the effects of adding poles and zeros to G(s)H(s) on the root loci.

b) Sketch the root locus for 0<K< , for the system with the open loop transfer function

)22)(2(

)()(2 +++

=ssss

KsHsG (5M+10M)

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G1

H2 H1

R(s) C(s)

- -

-

Figure 1

+ + G2

+

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Code No: R22026

5. Sketch the Bode plots for the following transfer functions and determine the system gain K for

the gain crossover frequency to be 10 rad/s (15M)

)12.0)(1()(

2.0

++=

−

sss

KesG

s

6. a) Enlist the step-by-step procedure for the construction of Nyquist plots.

b) A system is given by )12)(1(

14)(

2 ++

+=

sss

ssG .Sketch the Nyquist plot and hence determine

the stability of the system. (5M+10M)

7. a) What is compensation? What are the different types of compensators?

b) What is a lag compensator, obtain the transfer function of lag compensator and draw pole-

zero plot?

c) Explain the different steps to be followed for the design of compensator using Bode plot?

(2M+3M+10M)

8. a) Explain the Concepts of Controllability and Observability?

b) Obtain the state transition matrix for the state model whose A matrix is given by

c) Enumerate the properties of state transition matrix? (5M+5M+5M)

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Code No: R22026





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1. a) How are control systems classified?

b) Write the differential equations governing the behavior of the mechanical system shown in

figure 1 draw the mechanical network and obtain the transfer function. (6M+9M)

2. For the given electrical network Figure 2.

a) Obtain the signal flow graph

b) Compute the gain using the mason’s gain formula. (7M+8M)

3. a) What are the time domain specifications? Explain each of them.

b) A closed loop control system is represented by the differential equation

, where e = r-c is the error signal. Determine the undamped natural

frequency, damping ratio and percentage maximum overshoot for a unit step input.

(6M+9M)

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Code No: R22026

4. a) What do you mean by stability? Explain the qualitative and conditional stability?

b) Draw the complete root locus for )4)(2(

)()(++

=sss

KsHsG from the root locus plot, find

the range of values of K for which the system will have damped oscillatory response. Also,

determine the value of K for a damping ratio of ξ=0.5. (5M+10M)

5. a) Discuss the stability analysis from Bode plots.

b) Sketch the Bode plots for the following transfer functions and determine the system gain

K for the gain crossover frequency to be 10 rad/s (5M+10M)

)01.01)(1.01)(1()(

2

sss

KssG

+++=

6. a) What is the effect of adding a zero at origin to the to the open loop transfer

function on polar plot?

b) Sketch the polar plot of a system given by )12)(1(

1)(

2 ++=

ssssG . If the plot crosses the

real axis determine the corresponding frequency & magnitude (5M+10M)

7. a) What is lead compensator? When is it preferred?

b) Design a lag compensator that will provide a phase lag at 400 and alternation of 12 dB at 2

rad/sec. Determine its transfer function. (7M+8M)

8. a) Define i) State ii) State variable iii) State model

b) Construct the state model for a system characterized by the differential equation

.

c) Obtain the state transition matrix for the state model whose A matrix is given by

(3M+8M+4M)

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Code No: R22026





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1. a) Explain the limitations of closed loop system over open loop system.

b) Find the transfer function for the following mechanical system: Shown in figure 2

c) Define the term ‘impulse response of a system. (4M+8M+3M)

2. a) For the system represented in the given Figure 4 , obtain transfer function

b) Write down the signal flow equations and draw the signal flow graph for the above

system. (8M+7M)

3. a) Derive the expressions for rise time, peak over shoot, settling time of 2nd

order system of unit

step input.

b) A unit feedback system is characterized by an open-loop transfer function )5(

)(+

=ss

KsG

Determine the gain K so that the system will have a damping ratio of 0.5. For this value of

K determine settling time, peak overshoot and times to peak overshoot for a unit-step input.

(6M+9M)

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Code No: R22026

4. a) A feedback system has an open loop transfer function

( ) ( )( )952 ++

=sss

KsHsG

Determine by use of the Routh criterion, the maximum value of K for the closed loop

system to be stable.

b) A unity feedback system has the following open loop transfer function

Determine the stability of the system in terms of the parameter K. (7M+8M)

5. a) What are steps involved in constructing the Bode plot for a given G(jω)H(jω).

b) Sketch the magnitude and phase Bode plots. Determine the gain crossover frequency,

phase crossover frequency, gain margin and phase margin. (5M+10M)

)025.01)(25.01(

)1(20)(

2sss

ssG

++

+=

6. a) Define Polar plot? Explain how you can determine relative stability using polar plots.

b) Sketch the polar plot of a system given by )12)(1(

13)(

++

+=

sss

ssG . If the plot crosses

the real axis determine the corresponding frequency & magnitude (5M+10M)

7. a) Write the transfer function of a lag compensator and draw its polar plot and frequency

response plots.

b) Design a lead compensator that will provide a phase lead of 350 and again of 6.5 dB at 2.8

rad/sec. What will be the transfer function of the lead compensator that will satisfy the

above requirement? (7M+8M)

8. a) Test the controllability and observability of the system described by

b) Solve the following differential equation by converting it into state variable form

Where y(0)=0, (0) = 0; u(t)=unit step input. (8M+7M)

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Code No: R22026





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1. a) Distinguish between:

i) Linear and non linear control system

ii) Open loop and closed loop control systems

iii) Time invariant and time varying control systems.

Give an example for each of the above.

b) Find the transfer function of the following system show in figure.3 (8M+7M)

2. a) Derive the transfer function of an a.c. servomotor and draw its characteristics.

b) Explain the Synchro error detector with circuit diagram. (8M+7M)

3. a) What is the difference between type and order of a control system? Explain each with an

example?

b) The Figure 2 shows PD controller used for the system. Determine the value of Td so that

the system will be critically damped? Calculate it’s settling time? (5M+10M)

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Code No: R22026

4. a) Enumerate the limitations of Routh criterion. (5M+10M)

b) By means of the Routh criterion, determine the stability of the system represented by the

following characteristic equations. For systems found to be unstable, determine the number

of roots of the characteristic equation in the right half of the s-plane.

i) 0520102 234 =++++ ssss ii) 054322 23456 =++++++ ssssss

5. a) Define the following terms

i) Gain margin ii) Gain crossover frequency

iii) Phase margin iv) Phase crossover frequency v) Corner frequency

b) Sketch the magnitude and phase Bode plots. Determine the gain crossover frequency, phase

crossover frequency, gain margin and phase margin. (5M+10M)

)05.01)(5.01(

10)(

ssssG

++=

6. a) State Nyquist Stability Criterion? Explain the use of Nyquist Stability Criterion in the

assessment of relative stability of a system.

b) With the help of Nyquist plot assess the stability of a system )2)(1(

3)(

ssssG

++=

What happens to stability if the numerator of the function is changed from 3 to 30?

(7M+8M)

7. a) What is the purpose of using compensator? What is the basis for the selection of a particular

compensator?

b) Explain the design procedure of a lag-lead compensator in frequency domain. (5M+10M)

8. a) Test the observability of the system described by

b) For a system described by the state equation the response is

;

Determine the system matrix A and the state transition matrix Φ(t). (5M+10M)

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Code No: R22029


ELECTRICAL CIRCUIT ANALYSIS - II (Electrical and Electronics Engineering)


Answer any FIVE Questions

All Questions carry Equal Marks

~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Derive the relationship between line and phase quantities in a star-connected system with

the help of phasor diagram.

b) A balanced delta-connected load with R=50Ω per phase is fed from a three-phase 200V

supply as shown in Figure 1. Find the reading of wattmeter. (5M+10M)

2. a) What is the significance of phase sequence in a three phase system? How is a given phase

sequence be reversed?

b) A symmetrical three phase, three wire, 100V supply feeds an unbalanced star-connected

load with impedances of the load as 005∠=RZ , 0902∠=YZ and 0904 −∠=BZ . Find i)

line currents, ii) voltage across the impedances and iii) the displacement neutral voltage.

(7M+8M)

3. a) What is time constant? Explain time constant in case of series R-L and series R-C circuit.

Explain their properties and significance.

b) The switch in the circuit of Figure 2, is opened at t=0 after having been closed for very long

time. Determine i) the voltage across the switch at t = 0+? ii) v(t)for t > 0. (6M+9M)

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t = 0

- +

6 Ω

3 Ω

120V

1.5H 6 Ω

2 Ω

H2

1

+ v -

Figure 2

Figure 1

R

R

R

R

Y

B

V

M WL

C

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Code No: R22029

4. A sinusoidal voltage V(t) = Vm sin(wt+θ) is applied to a RC circuit at time t = 0. Assuming zero

initial charge on capacitor, find the complete solution for the current in the circuit using

Laplace transform method and differential equations (15M)

5. Find ABCD and h-parameters of the circuit in Figure 4 (15M)

6. a) What is positive real function? State the properties of positive real function.

b) Test the following function for positive realness. (5M+10M)

( ) .13

423

2

++

+=

ss

ssF

7. a) Discuss the general procedure of determing the Fourier series of a periodic waveform.

b) In a two element series network, voltage and current are given as

V(t) = 200 sin (314 t + 100) + 60 sin (942 t + 48

0)

i (t) 17 sin (314 t - 470) + 2 sin (942 t – 29.7

0)

Determine the two parameters, the impedance and the power factor of the circuit (9M+6M)

8. Determine the total solution for i(t) in the circuit of Figure 6 via the Fourier transform. (15M)

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+

V2

-

+

V1

-

1 Ω 1 Ω I1 I2 1 Ω

Figure 4

-j Ω -j Ω -j Ω

10V

2s t

vs(t)

Figure 6

vs(t)

2 Ω

2 Ω

i(t)

1/3 F

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Code No: R22029


ELECTRICAL CIRCUIT ANALYSIS - II (Electrical and Electronics Engineering)




~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Distinguish between star (3 and 4 wire) and delta connections. b) Each branch of a three-phase, star-connected load, consists of a coil of resistance 4 Ω and

reactance 5 Ω. This load is connected to a 400 V, 50 Hz supply. The power consumed is

measured using the two-wattmeter method. Sketch a circuit diagram showing the wattmeter

connections, and calculate the reading indicated by each meter. (5M+10M)

2. An unbalanced star-connected load is supplied from a symmetrical 3-phase, 440V, 3-wire

system. The branch impedances of the load are 0

1 3010∠=Z , 0

2 4510∠=Z and 0

3 6010∠=Z .

Determine the line currents and voltage across each impedance. (15M)

3. a) What is the significance of initial conditions? Write a note on initial conditions in basic

circuit elements.

b) Both switches in the circuit of Figure 1, are closed at t=0. Find i1(t), i2(t) and i3(t) for t > 0.

(5M+10M)

4. Find the current in the circuit shown in Figure 2 for t>0. At −= 0t the network was un

energized. (15M)

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SET - 2 R10

Figure 1

t= 0 0.8H

i 3

0.3V 0.2 V + -

10 Ω

+ -

10 Ω 40 Ω 20 Ω

t= 0

i 2 i 1

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Code No: R22029

5. Find the ABCD-parameters of the network shown in Figure 3. Verify the whether the circuit is

reciprocal. Also calculate the image parameters for the network. (15M)

6. a) Synthesize the impedance function ( )( )10

7072

+

++=

ss

sssZ


)4(

)9)(1()(

2

22

+

++=

ss

sssF

7. Determine the Fourier series of the signal shown in Figure 4. Where A =100 V, T = 25 П ms.

Determine the fundamental current in a series R-L circuit with R = 5Ω and L = 0.02 H. (15M)

8. Determine the total solution for i(t) in the circuit of Fig.5 via the Fourier transform. (15M)

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+

V2

-

+

V1

-

1 Ω 1 Ω

2 Ω 2 Ω

Figure 3

-T

V(t)

-T/2 T/2 T t

A

Figure 4

10V

2s t

vs(t)

Figure 5

vs(t)

1 Ω

1 Ω

i(t) 2

1F

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Code No: R22029


ELECTRICAL CIRCUIT ANALYSIS - II

(Electrical and Electronics Engineering)




~~~~~~~~~~~~~~~~~~~~~~~~

1. a) State the relative advantages of three phase systems compared with single phase systems.

b) A star-connected load, each phase of which has an inductive reactance of 40 Ω and

resistance of 25 Ω, is fed from the secondary of a three-phase, delta-connected transformer.

If the transformer phase voltage is 600 V, calculate i) the potential difference across each

phase of the load, ii) the load phase current, iii) the current in the transformer secondary

windings, and iv) the power and power factor. (5M+10M)

2. a) Discuss the phenomenon of neutral shift. In which type of load does it occur and why?

Derive an expression for calculating the neutral shift voltage.

b) A 3-phase star connected system with 230V between each phase and the neutral has

resistances of 4Ω, 5 Ω and 6 Ω respectively in their phases. Estimate the current flowing in

each phase and the neutral wire current. Find the total power absorbed. (7M+8M)

3. a) A capacitor with initial voltage vo is connected to resistor of R ohms at t=0, derive the

expression for the voltage across the capacitor and current through the capacitor at any time

t > 0 and plot the waveforms.

b) For the circuit shown in Fig.1 find i and v as functions of time for t > 0. (7M+8M)

4. a) For an R-L series circuit, a sinusoidal voltage of v (t) = Vm sin(ωt + φ) is applied at t=0.

Find the expression for transient current.

b) A series RL circuit with R=100 ohms and L= 1H has a sinusoidal voltage source

200sin(500t + φ) applied at time when φ = 0. i) Find the expression for current ii) At what

value of φ must the switch be closed so that the current directly enter steady state. (7M+8M)

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Figure 1

40 Ω

20 V 10 mH

50 Ω

t = 0

+

-

v

i

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Code No: R22029

5. Find the Z-parameter of the network in Fig.2 (15M)

6. a) Explain the difference between Cauer form and Foster form of realization.


158

45)(

24

35

++

++=

ss

ssssF

7. Determine the current i(t) in circuit shown in Figure 4 b. (15M)

8. Determine v(t) in the circuit of Fig.3 by using Fourier transform. (15M)

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+

V2

-

+

V1

-

1 Ω 1 Ω I1 I2 1 Ω

Figure 2

-j Ω -j Ω -j Ω

Figure 3

10e-3t

u(t)V

2 Ω

2 Ω v(t) 2

3F

3

1H

+

-

1 Ω 2H is(t)

i(t)

-2s

is(t)

-1s 1s 2s t

5A

Figure 4.a

3s

Figure 4.b

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Code No: R22029


ELECTRICAL CIRCUIT ANALYSIS - II





~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Derive the relationship between line and phase quantities in a delta-connected system with

the help of phasor diagram.

b) Calculate the readings of the two watt meters (W1 & W2) connected to measure the total

power for a balanced delta-connected load shown in Fig. 1, fed from a three-phase, 200 V

balanced supply with phase sequence as R-Y-B. The load impedance per phase is (14-j14)

Ω. Also find the line and phase currents, power factor, total power, total reactive VA and

total VA. (7M+8M)

2. a) Explain the consequences of disconnecting the neutral in a 3-phase 4-wire unbalanced

system

b) A three-phase, 415 V, 50 Hz supply is connected to an unbalanced, star-connected load,

having a power factor of 0.8 lagging in each phase. The currents are 40 A in the red phase,

55 A in the yellow phase, and 62 A in the blue phase. Determine i) the value of the neutral

current, and ii) the total power dissipated. (7M+8M)

3. a) A series R-L circuit with initial current I0 in the inductor is connected to a d.c voltage V at

t=0. Derive expression for the instantaneous current through the inductor for t > 0.

b) Find i (0+) in the circuit shown in Figure 2. (7M+8M)

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+

V

-

4k Ω i

t= 0

10 mA

Figure 2

0.01µF 5k Ω

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Code No: R22029

4. a) For an RC series circuit, a sinusoidal voltage v(t) = Vm sinωt is applied at t = 0. Find the

expression for transient current.

b) A sinusoidal voltage v = 250 sin 50 t is applied suddenly to series R-L circuit with R = 10 Ω

and L = 5H. Find the instant at which transient current becomes zero. (7M+8M)

5. Find the ABCD parameters of the network shown in Figure 3. (15M)

6. a) State the properties of LC driving point immitance functions.


2966

110106)(

23

23

+++

+++=

sss

ssssF

7. Determine the Fourier series of the half-wave rectified sine wave shown in Figure 4, where

T = 25 π. (15M)

8. Determine the voltage v(t)for the circuit shown in Figure 5b. (15M)

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Figure 3

1 Ω 1 Ω

2 Ω 2 Ω

1 Ω

2 Ω

Figure 5b

vs (t) +

v (t)

-

1/3 F

1 Ω

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Code No: R22024


ELECTRICAL MACHINES - II

(Electronics and Electronics Engineering)




~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Explain the classification of transformers.

b) Draw and explain the phasor diagram of transformer for lagging and leading loads?

(5M+10M)

2. a) Explain how variation in frequency affects the operation of a given transformer.

b) The parameters of a 2300/230 V, 50-Hz transformer are given below:

R1 = 0.286 Ω R2' = 0.319 Ω R0 = 250 Ω X1 = 0.73 Ω X2' = 0.73 Ω, X0 = 1250 Ω. The

secondary load impedance ZL = 0.387 + j 0.29. Solve the exact equivalent circuit with

normal voltage across the primary. (5M+10M)

3. a) With a neat circuit diagram explain about the Sumpner’s test conducted on transformer.

b) Explain the working of an auto transformer (8M+7M)

4. A ∆-∆ bank consisting of three 20-kVA, 2300/230-V transformers supplies a load of 40 kVA.

If one transformer is removed, find for the resulting V- V connection

i) kVA load carried by each transformer

ii) per cent of rated load carried by each transformer

iii) total kVA rating of the V-V bank

iv) ratio of the V-V bank to ∆ - ∆ bank transformer ratings.

v) per cent increase in load on each transformer when bank is converted into V-V bank. (15M)

5. a) Derive the condition for max torque under running conditions in 3 phase induction motors

induction motors.

b) A 3-phase, slip-ring, induction motor with star-connected rotor has an induced e.m.f. of 120

volts between slip-rings at standstill with normal voltage applied to the stator. The rotor

winding has a resistance per phase of 0.3 ohm and standstill leakage reactance per phase of

1.5 ohm. Calculate: i) rotor current/phase when running short-circuited with 4 percent slip

and ii) the slip and rotor current per phase when the rotor is developing maximum torque.

(8M+7M)

6. a) Explain about cogging and crawling in 3 phase induction motors.

b) Draw and explain phasor diagram of 3 phase induction motors. Obtain its equivalent circuit.

(8M+7M)

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Code No: R22024

7. A 3-ph, 400-V induction motor gave the following test readings;

No-load : 400 V, 1250 W, 9 A, Short-circuit : 150 V, 4 kW, 38 A

Draw the circle diagram. If the normal rating is 14.9 kW, find from the circle diagram, the full-

load value of current, p.f. and slip. (15M)

8. a) A 4-pole induction motor and a 6-pole induction motor are connected in cumulative cascade.

The frequency in the secondary circuit of the 6-pole motor is observed to be 1.0 Hz.

Determine the slip in each machine and the combined speed of the set. Take supply

frequency as 50 Hz.

b) Explain the speed control of 3-phase induction motor using stator voltage control. (8M+7M)

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Code No: R22024







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1. a) A single phase transformer takes 10A on no load at p.f. of 0.2 lagging. The turns ratio is 4 : 1

(step down). If the load on the secondary is 200 A at a p.f. of 0.85 lagging, find the primary

current and power factor. Neglect the voltage-drop in the winding.

b) Derive the e.m.f equation of a single phase transformer. (8M+7M)

2. a) Find the all-day efficiency of 500-kVA distribution transformer whose copper loss and iron

loss at full load are 4.5 kW and 3.5 kW respectively. During a day of 24 hours, it is loaded

as under :

No. of hours Loading in kW Power factor

6 400 0.8

10 300 0.75

4 100 0.8

4 0 –

b) Derive the condition for max efficiency in a transformer. (8M+7M)

3. a) The equivalent circuit for a 200/400-V step-up transformer has the following parameters

referred to the low-voltage side.

Equivalent resistance = 0.15 Ω; Equivalent reactance = 0.37 Ω

Core-loss component resistance = 600 Ω; Magnetizing reactance = 300 Ω. When the

transformer is supplying a load at 10 A at a power factor of 0.8 lag, Calculate: i) the primary

current ii) secondary terminal voltage.

b) An 11500/2300 V transformer is rated at 100 kVA as a 2 winding transformer. If the two

windings are connected in series to form an auto-transformer, what will be the possible

voltage ratios? (8M+7M)

4. a) Two T-connected transformers are used to supply a 440-V, 33-kVA balanced load from a

balanced 3-phase supply of 3300 V. Calculate: i) voltage and current rating of each coil

ii) kVA rating of the main and teaser transformer.

b) A balanced 3-phase load of 150 kW at 1000 V, 0.866 lagging power factor is supplied from

2000 V, 3-phase mains through single-phase transformers (assumed to be ideal) connected

in i) delta-delta ii) V-V. Find the current in the windings of each transformer and the

power factor at which they operate in each case. Explain your calculations with circuit and

vector diagrams. (8M+7M)

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Code No: R22024

5. Derive the inter relationship Rotor power input, rotor copper loss and mechanical power

developed of an induction motor? (15M)

6. a) Explain about the power stages in 3 phase induction motors.

b) Explain the relation between torque and rotor power factor in 3 phase induction motors.

(8M+7M)

7. Draw the circle diagram for a 3.73 kW, 200V, 50-Hz, 4-pole, 3-phase star-connected induction

motor from the following test data :

No-load : Line voltage 200 V, line current 5 A; total input 350 W

Blocked rotor : Line voltage 100 V, line current 26 A; total input 1700 W Estimate from the

diagram for full-load condition, the line current, power factor and also the maximum torque in

terms of the full-load torque. The rotor Cu loss at standstill is half the total Cu loss. (15M)

8. a) Two 50-Hz, 3-Ph induction motors having six and four poles respectively are cumulatively

cascaded, the 6-pole motor being connected to the main supply. Determine the frequencies

of the rotor currents and the slips referred to each stator field if the set has a slip of 2

percent.

b) Explain the speed control of 3-phase induction motor using frequency control. (8M+7M)

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Code No: R22024







~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Explain the working principle of an ideal transformer by using phasor diagram?

b) A 25-kVA transformer has 500 turns on the primary and 50 turns on the secondary winding.

The primary is connected to 3000-V, 50-Hz supply. Find the full-load primary and

secondary currents, the secondary e.m.f. and the maximum flux in the core. Neglect leakage

drops and no-load primary current. (8M+7M)

2. A 5-kVA, 2,300/230-V, 50-Hz transformer was tested for the iron losses with normal excitation

and Cu losses at full-load and these were found to be 40 W and 112 W respectively. Calculate

the efficiencies of the transformer at 0.8 power factor for the following kVA outputs :

1.25 2.5 3.75 5.0 6.25 7.5

Plot efficiency vs kVA output curve. (15M)

3. a) A 5 kVA 200/1000 V, 50 Hz, single-phase transformer gave the following test results :

O.C. Test (L.V. Side) : 2000 V, 1.2 A, 90 W

S.C. Test (H.V. Side) : 50 V, 5A, 110 W

i) Calculate the parameters of the equivalent circuit referred to the L.V. side.

ii) Calculate the output secondary voltage when delivering 3 kW at 0.8 p.f. lagging, the

input primary voltage being 200 V.

iii) Find the percentage regulation.

b) A 5 kVA, 110/110 V, single-phase, 50 Hz transformer has full-load efficiency of 95% and

an iron loss of 50 W. The transformer is now connected as an auto-transformer to a 220 V

supply. If it delivers a 5 kW load at unity power factor to a 110 V circuit, calculate the

efficiency of the operation and the current drawn by the high-voltage side. (8M+7M)

4. A load of 1000 kVA at 0.866 p.f. lagging is supplied by two 3 phase transformers of 800 kVA

capacity operating in parallel. Ratio of transformation is same: 6600/400 V, delta/star. If the

equivalent impedances referred to secondary are (0.005 + j.015) ohm and (0.012 + j0.030) ohm

per phase respectively. Calculate load and power factor of each transformer. (15M)

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Code No: R22024

5. a) Explain the working principle of 3 phase induction motors.

b) A 4-pole, 3-phase induction motor operates from a supply whose frequency is 50Hz.

Calculate:

i) the speed at which the magnetic field of the stator is rotating.

ii) the speed of the rotor when the slip is 0.04.

iii) the frequency of the rotor currents when the slip is 0.03.

iv) the frequency of the rotor currents at standstill. (10M+5M)

6. a) Explain the torque slip characteristics of 3 phase induction machines

b) The power input to the rotor of 440 V, 50 Hz, 6-pole, 3-phase, induction motor is 80kW.

The rotor electromotive force is observed to make 100 complete alterations per minute.

Calculate: i) the slip, ii) the rotor speed, iii) rotor copper losses per phase. (8M+7M)

7. Draw the circle diagram from no-load and short-circuit test of a 3-phase 14.92 kW, 400V, 6-

pole induction motor from the following test results (line values).

No-load : 400V, 11 A, p.f. = 0.2

Short-circuit : 100V, 25 A, p.f. = 0.4

Rotor Cu loss at standstill is half the total Cu loss. From the diagram, find: a) line current, slip,

efficiency and p.f. at full-load b) the maximum torque. (15M)

8. a) Explain the working principle of Induction generators.

b) Explain about the cascaded operation of 3-phase induction motors. (8M+7M)

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Code No: R22024







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1. a) Explain about the construction of Transformer.

b) Explain about a single phase transformer on load by using phasor diagram. (8M+7M)

2. a) In a 25-kVA, 2000/200 V, single-phase transformer, the iron and full-load copper losses are

350 W and 400 W respectively. Calculate the efficiency at unity power factor on i) full load

ii) half full-load.

b) Explain about various losses in a transformer. (8M+7M)

3. The low voltage winding of a 300kVA, 11,000/2500V, 50-Hz transformer has 190 turns and a

resistance of 0.06. The high-voltage winding has 910 turns and a resistance of 1.6Ω. When the

l.v. winding is short-circuited, the full-load current is obtained with 550-V applied to the h.v.

winding. Calculate: i) the equivalent resistance and leakage reactance as referred to h.v. side

and ii) the leakage reactance of each winding. (15M)

4. Explain about three phase to two phase transformation using Scott connection . (15M)

5. a) Explain the production of rotating magnetic field in 3 phase induction motors.

b) List out the advantages and disadvantages of 3 phase induction motors (10M+5M)

6. a) A 440V, 3-phase , 50-Hz, 4-pole, Y-connected induction motor has a full-load speed of 1425

rpm. The rotor has an impedance of (0.4 + j4) ohm and rotor/stator turn ratio of 0.8.

Calculate: i) full-load torque ii) rotor current and full-load rotor Cu loss iii) power output

if windage and friction losses amount to 500 W. iv) maximum torque and the speed at

which it occurs v) starting current and vi) starting torque.

b) The maximum torque of a 3-phase induction motor occurs at a slip of 12%. The motor has

an equivalent secondary resistance of 0.08Ω /phase. Calculate the equivalent load resistance

RL, the equivalent load voltage VL and the current at this slip if the gross power output is

9,000 watts. (8M+7M)

7. A 415V, 29.84 kW, 50-Hz, delta-connected motor gave the following test data :

No-load test : 415 V, 21 A, 1,250 W

Locked rotor test : 100 V, 45 A, 2,730 W

Construct the circle diagram and determine:

a) the line current and power factor for rated output

b) the maximum torque. Assume stator and rotor Cu losses equal at standstill. (15M)

8. a) Explain the speed control of 3-phase induction motor using pole changing method

b) A certain 3-phase, 6-pole, 50-Hz induction motor when fully-loaded, runs with a slip of 3%.

Find the value of the resistance necessary in series per phase of the rotor to reduce the speed

by 10%. Assume that the resistance of the rotor per phase is 0.2 ohm. (8M+7M)

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Code No: R22022


POWER SYSTEMS - I (Electrical and Electronics Engineering)




~~~~~~~~~~~~~~~~~~~~~~~~

1. Draw the complete schematic diagram of a coal fired thermal power plant with all the

components. Explain briefly the function of each component. (15M)

2. a) Discuss briefly the environment pollution by radio active materials of a nuclear power plant.

b) Describe with a neat sketch the construction and principle of a nuclear power plant.

(8M+7M)

3. a) Explain briefly the working principle of a gas turbine plant through a neat sketch with all its

components.

b) What are the advantages and disadvantages of a gas turbine plant compared to conventional

coal fired thermal power plant? (8M+7M)

4. a) What is meant by radial and ring type of distribution systems? Explain.

b) A two wire distributors are fed at F1 and F2 at 230 V and 220 V respectively. Loads of 150

A and 100 A are taken at points P and Q. Resistance of both the conductors between F1 P is

0.03Ω, between PQ is 0.05 Ω and between QF2 is 0.02 Ω. Determine the current in each

section of the distributor and voltage at each load point. (8M+7M)

5. a) What are the considerations for the selection of a suitable site for an outdoor substation?

b) What is a busbar? Briefly explain the common arrangement of bus bars by suitable single

line diagrams. (8M+7M)

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Code No: R22022

6. a) State the properties of different insulating materials used for cables.

b) A 33 kV 3-phase underground cable, 4 km long, uses the single-core cable. Each of the

conductors has a diameter of 2.5 cm and radial thickness of insulation is 0.5 cm. The

relative permeability of the dielectric is 3.0. Determine the following: (7M+8M)

i) Capacitance of the cable per phase

ii) Charging current per phase

iii) Total charging KVAR

iv) Dielectric loss per phase if the power factor of the unloaded cable is 0.02

v) Maximum stress in the cable

7. a) Explain briefly the plant capacity factor and plant use factor and explain their importance in

an electrical supply system.

b) A generating station has the following daily load cycle: (7M+8M)

Time(hrs) 0-6 6-10 10-12 12-16 16-20 20-24

Load(MW) 40 50 60 50 70 40

Draw the load curve and find the following: i) Maximum demand ii) Units generated per

day iii) Average load and load factor

8. a) Discuss the flat rate and block rate tariff methods for cost calculation of generation.

b) What are the factors influencing the tariff design? (8M+7M)

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Code No: R22022






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1. Draw the general layout of a modern thermal power plant showing all the parts with brief

description including the flue gases. (15M)

2. a) Describe the different types of fuels used in a nuclear power plant and discuss the problems

associated with the disposal of nuclear waste.

b) Discuss briefly the environmental pollution by radioactive materials of a nuclear power

plant. (8M+7M)

3. a) Discuss briefly about solar power generation.

b) What are the advantages and disadvantages of a gas turbine plant? (7M+8M)

4. a) Discuss briefly ring main distribution systems and its advantages?

b) A 2-wire DC distributor of 400 meters long supplies a uniformly distributed lighting load of

1 A per meter. There are connected loads of 120, 72, 48 and 120 amps at 40, 120, 200 and

320 meters respectively from the end A. The distributor has a resistance of 0.15 ohm per km

run. Determine the currents at both ends and lowest voltage point if the distributor is fed at

250 V from both ends. (7M+8M)

5. a) Explain the working principle of the main and a transfer bus bar system with circuit diagram.

b) Compare the technical features of air insulated substations and gas insulated substations.

(8M+7M)

6. a) What is meant by grading of cables? Explain why and how the grading of cables is done.

b) A single core cable has a conductor diameter of 2.5 cm and a sheath of inside diameter 6cm.

Calculate the maximum stress. It is desired to reduce the maximum stress by using two

inter sheaths. Determine their best position, the maximum stress and the voltage on each:

System voltage is 3-phase 66 kV. (8M+7M)

7. a) Explain clearly how a good load factor and a good diversity factor help to keep overall cost

of generation low. (7M+8M)

b) The peak load on a 50MW power station is 39 MW. It supplies power through for

transformers whose connected loads are 17, 12, 9 and 10 MW. The maximum demands on

these transformers are 15, 10, 8 and 9 MW respectively. If the annual load factor is 50% and

the plant is operating for 65% of the period in the year, find out the following:

i) Average load on the station ii) Energy supplied per year iii) Demand factor

iv) Diversity factor v) Use factor for the power station.

8. a) What are the objectives and requirements of tariff for generation cost calculation?

b) Explain briefly the following tariff methods: (7M+8M)

i) Flat rate tariff ii) Two-part tariff

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Code No: R22022


POWER SYSTEMS - I





~~~~~~~~~~~~~~~~~~~~~~~~

1. Draw a typical layout of a thermal power plant and explain the functions of the following

components. (15M)

a) Coal and ash handling b) Steam generating plant

c) Steam turbines d) Feed water circuit e) Flue gases.

2. a) Explain briefly the mechanism of energy release in a nuclear reaction.

b) Describe with the help of a neat sketch the construction and working of a pressurized water

reactor (PWR). Mention the merits and demerits of PWR. (7M+8M)

3. a) Discuss about solar power generation and solar energy storage through a line diagram.

b) What are the components in a gas turbine plant? Discuss them briefly. (7M+8M)

4. a) Discuss the classification of distribution systems.

b) A 300 m ring distributor has loads as shown below, where distances are in meters. The

resistance of each conductor is 0.4 ohms per km and the loads are tapped off at points B, C

and D as shown. If distributor is fed at A with 240 V supply, find voltages at B, C and D.

(7M+8M)

5. a) Explain the different busbar arrangements in a substation with relavent diagrams.

b) Describe the working of an air insulated substation with a single line diagram. (8M+7M)

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Code No: R22022

6. a) Discuss the general criterion of classification of underground cables? Discuss the insulation

mechanism of cables?

b) Explain briefly the following methods of grading of cables: (7M+8M)

i) Capacitance grading ii) Inter sheath grading

7. a) What is the significance of load curves and load duration curves?

b) Define the following terms: (8M+7M)

i) Demand factor ii) Load factor iii) Utilization factor iv) Diversity factor

8. a) What are the objectives of tariff and factors influencing the tariff design?

b) The expected annual cost of the power system supplying the energy to 40,000 consumers is

tabulated below:

Fixed charges = Rs.2400 × 103

Energy charges = Rs.1716 × 103

Consumer charges = Rs.210 × 103

Profit = Rs.168 × 103

Maximum demand = 5000 kW

Diversity factor = 4

Energy supplied = 17×106

kWh

Devise a three-part tariff allowing 25% of the profit in fixed charges, 50% in energy charges

and remaining 25% in customer charges. (7M+8M)

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Code No: R22022






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1. Draw the general layout of a modern thermal power plant and explain the function of the

following: (15M)

i) Economizer ii) Electrostatic precipitator iii) Turbine

iv) Cooling Towers v) Boiler

2. a) What are the factors to be considered while designing a nuclear power plant?

b) Describe with the help of a neat sketch the construction and working of boiler water reactor

(BWR). Discuss its merits and demerits. (7M+8M)

3. Explain the principle and operation of a gas power station with a single line diagram and

discuss their components briefly. (15M)

4. a) What is meant by radial and ring main systems of distribution? Discuss briefly the

requirements of a distribution system.

b) A 2- wire DC distributor AB 300 m long and is fed from both ends and supplies a

uniformly distributed load of 0.15amps per meter length together with the following

concentrated loads: 50A at C; 60A at D and 40A at E, distances AC, CD and DE being 75,

100 and 50 meters respectively. If the supply voltages at A and B are 205 and 200 volts

respectively and the resistance of each conductor is 0.00015 ohms per meter, calculate the

current supplied at each end and the point of minimum potential. (7M+8M)

5. a) Discuss the layout of a substation through a suitable line diagram showing the location of

all the substation equipment.

b) Explain the single bus bar system with sectionalization with its merits and demerits.

(7M+8M)

6. a) Explain the significance of insulation and grading of cables.

b) Discuss in detail different insulating materials commonly used for cables. (8M+7M)

7. a) Define the following:

i) Connected load ii) Maximum demand iii) Demand factor.

b) A power supply is having the following loads. (7M+8M)

Type of load Max.demand (KW) Diversity of group Demand factor

Domestic 15,000 1.25 0.7

Commercial 25,000 1.2 0.9

Industrial 50,000 1.3 0.98

If the overall system diversity factor is 1.5, determine

i) The maximum demand ii) Connected load of each type

8. a) What is meant by tariff and mention its objectives by using an example? (7M+8M)

b) Explain Flat Rate and Block-Rate tariff methods for calculating the cost of generation.

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Code No: R22021


PULSE AND DIGITAL CIRCUITS (Com. to EEE, ECE, ECC, BME, EIE)

Time: 3 hours Max Marks: 75



~~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Obtain the response of an RC low pass circuit for a step input.

b) Draw the circuit diagram of RLC based ringing circuit and explain its operation.

2. a) Draw the basic circuit diagram of negative peak clamper circuit and explain its operation.

b) Draw the circuit diagram of slicer circuit using zener diodes and explain its operation with

the help of its transfer characteristic.

3. a) Define the transistor switching times:

i) delay time ii) rise time iii) storage time and iv) fall time.

b) Draw the circuit diagram of RTL logic gate and explain its operation with the help of truth

table.

4. a) Draw the circuit diagram of a fixed bias binary with speed up capacitors.

b) Explain the method of symmetrical triggering with relevant diagram.

5. Design a collector coupled monostable multivibrator employing two n-p-n silicon transistors

with 5 msec as its quasi stable state duration. Make reasonable assumptions.

6. a) Write the differences between the voltage and current time base generators?

b) Discuss the concept of Bootstrap Time Base Generator.

7. a) What is relaxation? With neat circuit diagram explain the principle of operation of a voltage

sweep circuit using UJT.

b) Define and explain the following terms: i) Phase delay and ii) Phase jitter

8. a) Explain a method of triggering a blocking oscillator with the help of circuit diagram.

b) With neat circuit explain operation of bi-directional sampling gate using transistors.

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1. a) Obtain the condition for an RC high pass circuit to behave as a good differentiator.

b) What is a double differentiator circuit? Draw and explain its response to ramp input.

2. a) Draw the shunt clipper that clips the sine wave signal above +5V and explain its working

with waveforms.

b) Explain the response of the clamping circuit when a square wave input is applied under

steady state conditions.

3. a) With the help of neat wave forms explain the transition time of a diode.

b) Compare the Resistor Transistor and Diode Transistor logic families.

4. a) Explain the reason for the occurrence of overshoot at the base of normally ON transistor of

one shot. Derive an expression for overshoot.

b) Explain how a Schmitt trigger can be used as a comparator and as a squaring circuit.

5. Draw the circuit diagram of collector coupled transistor astable multivibrator. Explain its

operation and also derive an expression for the time period.

6. a) Explain how UJT is used for sweep circuit?

b) Draw the circuit diagram of Transistor Miller time base generator and give the requirement

of each component.

7. a) Explain the need for synchronization.

b) With neat circuit diagram and waveforms, explain the pulse synchronization of an astable

relaxation circuit.

8. a) Explain the operation of astable transistor blocking oscillator with diode control.

b) Differentiate different types of uni-directional diode sampling gate.

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1. a) Obtain the expression for the gain A and phase angle Φ of an RC low pass circuit. Sketch

the frequency response and find the expression for higher cutoff frequency.

b) A symmetrical square wave of 20V peak to peak amplitude with zero average value and with

a fundamental time period ‘T’ is given as input of an RC low pass circuit. Obtain the

expression for peak-to-peak value of the output signal.

2. a) Classify different types of clipper circuits. Give their circuits and explain their operation

with the aid of transfer characteristics.

b) State and prove clamping-circuit theorem.

3. a) Design the transistor switch for the following specifications: Vin= ±3Vsquare wave,

VCC=10V, IC=1mA, hFE=50. Assume Si transistor.

b) Why totem pole is used in DTL? Draw circuit diagram and explain a DTL gate with this.

4. a) Discuss symmetrical and asymmetrical triggering in case of bi-stable transistor

multivibrator.

b) Design a transistor Schmitt trigger circuit employing two n-p-n silicon transistors which

has its upper tripping point at 6V and lower tripping point at 4V. Assume that VCC=18V,

IC(sat)=4mA and hFE(min)=20.

5. a) Describe how the gate width T of an emitter coupled monostable multivibrator can be

linearly varied by adjusting the bias voltage V through a dc potentiometer.

b) Design an Astable Multivibrator to generate 5 kHz square wave.

The supply voltage VCC=10V, IC(sat)=10mA, hFE(min)=50 and assume Si transistors.

6. a) Explain how an inductor L can be used to improve the linearity of a simple RC sweep

circuit.

b) How does sync signal amplitude will affect frequency of operation of the sweep generator?

7. a) Explain the factors which influence the stability of a relaxation divider with the help of a

neat waveforms

b) Explain how the synchronization of a sweep circuit is achieved with symmetrical signals.

8. a) Explain the principle of operation of monostable blocking oscillator with base timing.

Sketch the current waveforms and derive an expression for current pulse width.

b) What is pedestal? How it effect the output of sampling gates?

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Code No: R22021






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1. a) What is low pass RC circuit? Derive an expression of output voltage for square wave input

and draw input-output characteristics of this circuit

b) Explain the operation of RC high pass circuit when exponential input is applied.

2. a) Derive the steady state response of a clamping circuit for a square wave input in which the

resistance Rs of the signal source is taken into account.

b) Design a diode clamper circuit to clamp the positive peaks of the input signal at zero level.

The frequency of the input signal is 500Hz.

3. a) Derive expressions for rise and fall time of a transistor in terms of the transistor Parameters

and operating currents.

b) Verify the truth table of RTL NOR gate with the circuit diagram of two inputs.

4. a) What are the basic techniques in the triggering of Bistable Multivibrator? Explain the

techniques with neat diagrams.

b) Design a self bias bi-stable multivibrator employing two p-n-p silicon transistors to

operate at a maximum frequency of 60Hz. Assume that VCC=15V, RC=2.2kΩ,

VCE(sat)=0.4V, VBE(sat)=0.95V, hFE=30 and the impedance of the trigger source RS=680Ω.

5. a) Explain the operation of a collector coupled transistor monostable multivibrator with the

help of a neat circuit diagram and waveform.

b) Write short notes on triggering of monostable multivibrators

6. a) With a neat circuit, explain a method of compensation used to improve the linearity of

bootstrap time base circuit.

b) Compare a transistor-switch sweep circuit with UJT sweep circuit with respect to sweep

speed and linearity of sweep.

7. a) What is phase jitter? Discuss the significance of it in a frequency divider.

b) A UJT sweep operates with VV=3V, Vp=16V and η=0.5. A sinusoidal synchronizing voltage

of 2V peak is applied between bases and the natural frequency of the sweep is 1 kHz, over

what range of sync signal frequency will the sweep remain in 1:1 synchronism with the sync

signal?

8. a) Derive an expression for the pulse width of a triggered transistor blocking oscillator

with base timings.

b) Derive the gain and control voltages of four diode sampling gate.

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Code No: R22023


SWITCHING THEORY AND LOGIC DESIGN (Com. to EEE, ECE, ECC, BME, EIE)




~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Convert the following to binary and then to gray code.

i) 234516 ii) 123416 iii) 23458

b) Perform the following using BCD arithmetic.

i) 712910 + 771110 ii) 812410 + 812710

2. a) Show that both NAND gate and NOR gate are universal gates.

b) Simplify the following Boolean expressions to a minimum number of literals.

i) CBABA ++ ii) )]([ XZXYZYX ++

iii) CAABCCA ++ to three literals iv) )()( CDAABDCDBA +++ to one literal

v) ))()(( DCBACACA ++++ to one literal

3. a) Reduce the following expressions using K-map

i) CBCBACBAAB +++ ii) ABCCBAADCCAAB +++++

b) Obtain the simplified expressions in sum of products for the following Boolean functions

using K-map

i) ∑= )15,14,13,7(),,,( DCBAF ii) ∑= )15,14,13,12,3,2(),,,( zyxwf

4. a) Design a full adder with two half adders and OR gate.

b) Design a Excess-3 adder using 4-bit parallel binary adder and logic gates.

5. a) Distinguish between a multiplexer and a Demultiplexer.

b) Design a full adder using 8×1 MUX.

6. a) Differentiate between PROM and EPROM.

b) Tabulate the PLA programming table for the four Boolean functions listed below.

∑= )6,4,2,1,0(),,(1 mCBAf

∑= )7,6,2,0(),,(2 mCBAf

∑= )6,3(),,(3 mCBAf

∑= )7,5,3,1(),,(4 mCBAf

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Code No: R22023

7. a) Realize D Flip-Flop using JK Flip-Flop.

b) Realize a master slave JK Flip Flop using NAND gates and explain its operation and point

out how race condition is avoided.

8. a) A clocked sequential circuit is defined by the following state-table: Obtain minimal state

table.

b) Give proper assignment and hence design the circuit using T - Flip-Flops.

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Code No: R22023






~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Convert the following to Decimal and then to Hexadecimal.

i) 32148 ii) 45678 iii) 101011012

b) Perform the subtraction with the following unsigned binary numbers by taking the 2’s

complement of the subtrahend.

i) 11010 – 10010 ii) 11011 – 1101 iii) 100 – 110000 iv) 1010100 – 1010100

2. a) Show that the dual of the exclusive-OR is equal to its complement.

b) Express the complement of the following functions in sum of min terms

i) ∑= )14,13,11,6,2,0(),,,( DCBAF ii) )7,6,3,0(),,( ∏=zyxF

3. a) The following function should be simplified using K-map

i) ∑= )7,5,3,1(),,( zyxf ii) ∑= )7,6,5,3,2,1(),,( zyxf

iii) ∑= )7,5,2,0(),,( zyxf

b) Simplify the following Boolean functions using K-map technique

∑= )31,29,27,26,25,24,16,11,10,9,8,7,4,0(),,,,( mEDCBAf

4. a) Implement full adder circuit using ROM and verify the working.

b) Realize a look ahead carry adder.

5. a) Implement the following function:

∑= )14,12,10,7,4,3,1,0(),,,( DCBAf Using i) 16×1 MUX ii) 4×1 MUX

b) Design a circuit to convert excess-3 code to BCD code using a 4-bit full adder.

6. a) What is the basic architecture of a PLA.

b) Implement the following two Boolean functions with a PLA

∑= )4,2,1,0(),,(1 mCBAF ∑= )7,6,5,0(),,(2 mCBAF

7. a) Design a Mod-6 synchronous counter using J-K flip flops.

b) Explain the following:

i) Race-around condition in flip flop ii) J-K Master slave flip flop

8. A clocked sequential circuit is provided with a single input x and single output Z. Whenever

the input produce a string of pulses 1 1 1 or 0 0 0 and at the end of the sequence it produce an

output Z = 1 and overlapping is also allowed.

a) Obtain State - Diagram.

b) Also obtain state - Table.

c) Find equivalence classes using partition method & design the circuit using D- flip-flops.

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Code No: R22023






~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Convert the following to binary and then to gray code.

i) 12578 ii) 77710 iii) 99910

b) Convert the following.

i) AB16 = ( )10 ii) 12348 = ( )10 iii) 101100112 = ( )10 iv) 77210 = ( )16

2. a) What is a parity bit? How many types of parity are there? Why is odd parity used more often

than even parity?

b) i) Given BCAACthatshowCBAAB =+=+ ,

ii) ),)()(( DCBACACA ++++ Simplify.

3. Obtain the minimal expression for ∑= )15,13,12,9,8,7,6,5,3,2,1(mf using the tabular

method

4. a) Design a combinational logic to subtract one bit from the other. Draw the logic diagram

using NAND and NOR gates.

b) Give the NAND gate realization of full-adder.

5. a) Given a 32 x 8 ROM clip with an enable input, show the external connection necessary to

construct a 128 x 8 ROM with four chips and a decoder.

b) Design a 32:1 Multiplexer using two 16:1 and 2:1Multiplexers.

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Code No: R22023

6. a) What are the advantages and disadvantages of using a PROM as a PLD?

b) Implement the following Boolean functions using PAL.

∑= )13,12,10,8,7,5,2,0(),,,(1 mzyxwf

∑= )15,14,9,8,6,2,0(),,,(2 mzyxwf

∑= )15,14,8,0(),,,(3 mzyxwf

∑= )10,9,8,5,4,2,1,0(),,,(4 mzyxwf

7. a) Define the following terms as applied to flip flops.

i) Set-up time ii) hold time

iii) Propagation delay time iv) maximum clock frequency

b) Convert an SR flip flop into

i) T flip flop ii) JK flip flop iii) D flip flop

8. a) Convert the given Mealy Machine to Moore Machine.

b) A clocked sequential circuit with two inputs x and y and a single output Z is defined by the

following state diagram. Design the circuit using T flip-flop.

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Code No: R22023






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1. a) Perform subtraction with the following unsigned decimal numbers by taking 10’s

complement of the subtrahend. Verify the result.

i) 5250- 1321 ii) 1753 – 8640 iii) 20 – 100 iv) 1200 – 250

2. a) Derive the Boolean expression for a two input Ex-OR gate to realize with two input NAND

gates without using complemented variables and draw the circuit.

b) Reduce the circuit given in figure after simplification.

3. a) Define the following terms:

i) Prime implicant ii) Essential prime implicant

b) What are dominating rows & dominating columns?

c) Simplify the following Boolean functions using K-map technique

∑= )27,25,23,22,20,19,18,16,11,9,7,6,4,3,2,0(),,,,( mEDCBAf

4. a) Write the design steps of adder? Design half adder with NAND gates.

b) Design of full subtractor with two half subtractors and OR gate.

5. a) Explain how a 4-variable function can be realized using an 8:1 MUX.

b) Design 4 to 16 decoder using 2 to 4 decoders and basic gates.

6. a) Implement the following Boolean functions using PLA.

∑= )5,3,1,0(),,(1 mCBAf ∑= )7,5,3,0(),,(2 mCBAf

b) Give the comparison between PROM, PLA and PAL.

7. a) Design a 4-bit binary synchronous counter with D flip-flops.

b) Compare synchronous & asynchronous circuits

8. a) What are the Moore and Mealy machines? Compare them.

b) What are the capabilities and limitations of FSM?

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code no: r22026 r10 set - 1 ii b. tech ii semester ... no: r22026 ii b. tech ii semester...

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