2023 100306

B.Tech 3rd Semester Examination, 2023

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer of the following (Any seven question only):

Q1.1

Kirchhoff's Current law is based on law of conservation of

a)

energy

b)

momentum

c)

mass

d)

charge

Q1.2

Determine the current if a 20 coulomb charge passes a point in 0.25 seconds

a)

10 A

b)

20 A

c)

2 A

d)

80 A

Q1.3

Comment on the linearity of $ y[n]=n*x[n] $.

a)

Linear

b)

Only additive

c)

Not scalable

d)

Non linear

Q1.4

Maximum power transfer occurs at a

a)

100% efficiency

b)

50% efficiency

c)

25% efficiency

d)

75% efficiency

Q1.5

The inverse laplace transform of $ \frac{1}{s} - \frac{e^{-as}}{s} $ is

a)

U(t)U(ta)U(t)-U(t-a)

b)

U(t)U(t)

c)

U(ta)U(t-a)

d)

Zero

Q1.6

The parameter A of a two port network is equal to

a)

V2/V1V_{2}/V_{1} with I1=0I_{1}=0

b)

V1/I2V_{1}/I_{2} with V2=0V_{2}=0

c)

I1/I2I_{1}/I_{2} with V2=0V_{2}=0

d)

V1/V2V_{1}/V_{2} with I2=0I_{2}=0

Q1.7

A system is linear if it satisfies

a)

Principle of superposition

b)

Principle of homogeneity

c)

Both (i) & (ii)

d)

Only (i)

Q1.8

Given $ F(S)=(S+2)/S(S+1) $ the initial and final values of f(t) will be respectively

a)

1, 2

b)

2, 1

c)

1, 1

d)

2, 2

Q1.9

Time constant of RL circuit is

a)

L/RL/R

b)

RL

c)

R/LR/L

d)

None of the above

Q1.10

The transmission parameters are also known as:

a)

impedance parameters

b)

ABCD parameters

c)

admittance parameters

d)

hybrid parameters

Q.2 Solve both questions :

Q2.1

A series R-L circuit has $ R=2 \Omega $ and $ L=2H $. A ramp input r(t) is applied at $ t=1 \text{ sec} $. Obtain an expression for current through the circuit.

Q2.2

Define time constant. What the significance of time constant?

Q.3 Solve both questions :

Q3.1

State Superposition theorem explaining the conditions in which it is valid.

Q3.2

In the network shown in figure below, find the value of current flowing through the 6 ohm resistance in the circuit given below using superposition theorem.

Question Diagram

Q.4 Solve both questions :

Q4.1

State and explain Thevenin's Theorem. Show the Thevenin's equivalent representation of any circuit.

Q4.2

For the circuit given below, determine the current flowing through the 4 ohm resistance by Thevenin's theorem. What are the values of Thevenin's resistance and Thevenin's voltage for this circuit.

Question Diagram

Q.5 Solve both questions :

Q5.1

Calculate the Laplace Transform of the function $ f(t)=e^{-t}\sin(wt) $.

Q5.2

Define Gate function? Using Gate function find out the Laplace Transform of a single Sine wave.

Question Diagram

Q.6 Solve both questions :

Q6.1

Calculate the impedance, resistance, Power and power factor of a circuit whose expression for voltage and current are given by: $ V = 100\sin(wt+60^{\circ}) - 50\sin(5wt-30^{\circ}) \text{ volt} $ and $ I = 10\sin(wt+60^{\circ}) - 5\sin(3wt+30^{\circ}) \text{ amp} $.

Q6.2

A 400 mH coil of zero resistance is connected to an AC circuit in which 6 mA current is flowing. Find out the voltage across the coil if the frequency is 100 Hz.

Q.7 Solve this question :

Q7.1

Obtain the Y & Z parameters of the network shown below. Write the unit of all individual parameters.

Question Diagram

Q.8 Solve both questions :

Q8.1

Explain frequency response. Why magnitude and phase plots are necessary for frequency response analysis.

Q8.2

What is Q-factor? Calculate the quality factor of a series RLC circuit with $ L=2H $, $ C=2\mu F $ and $ R=20 \Omega $.

Q.9 Write short notes on any two of the following:

Q9.1
a)

Norton's Theorem

b)

Reciprocity Theorem

c)

Hybrid Parameters of a 2-port network

d)

Duality and Dual Network


2023 V4 100306

B.Tech 3rd Semester Examination, 2023

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer of the following (Any seven question only):

Q1.1

Kirchhoff's Current law is based on law of conservation of

a)

energy

b)

momentum

c)

mass

d)

charge

Q1.2

Determine the current if a 20 coulomb charge passes a point in 0.25 seconds

a)

10 A

b)

20 A

c)

2 A

d)

80 A

Q1.3

Comment on the linearity of $ y[n]=n*x[n] $.

a)

Linear

b)

Only additive

c)

Not scalable

d)

Non linear

Q1.4

Maximum power transfer occurs at a

a)

100% efficiency

b)

50% efficiency

c)

25% efficiency

d)

75% efficiency

Q1.5

The inverse laplace transform of $ \frac{1}{s} - \frac{e^{-as}}{s} $ is

a)

U(t)U(ta)U(t)-U(t-a)

b)

U(t)U(t)

c)

U(ta)U(t-a)

d)

Zero

Q1.6

The parameter A of a two port network is equal to

a)

V2/V1V_{2}/V_{1} with I1=0I_{1}=0

b)

V1/I2V_{1}/I_{2} with V2=0V_{2}=0

c)

I1/I2I_{1}/I_{2} with V2=0V_{2}=0

d)

V1/V2V_{1}/V_{2} with I2=0I_{2}=0

Q1.7

A system is linear if it satisfies

a)

Principle of superposition

b)

Principle of homogeneity

c)

Both (i) & (ii)

d)

Only (i)

Q1.8

Given $ F(S)=(S+2)/S(S+1) $ the initial and final values of f(t) will be respectively

a)

1, 2

b)

2, 1

c)

1, 1

d)

2, 2

Q1.9

Time constant of RL circuit is

a)

L/RL/R

b)

RL

c)

R/LR/L

d)

None of the above

Q1.10

The transmission parameters are also known as:

a)

impedance parameters

b)

ABCD parameters

c)

admittance parameters

d)

hybrid parameters

Q.2 Solve both questions :

Q2.1

A series R-L circuit has $ R=2 \Omega $ and $ L=2H $. A ramp input r(t) is applied at $ t=1 \text{ sec} $. Obtain an expression for current through the circuit.

Q2.2

Define time constant. What the significance of time constant?

Q.3 Solve both questions :

Q3.1

State Superposition theorem explaining the conditions in which it is valid.

Q3.2

In the network shown in figure below, find the value of current flowing through the 6 ohm resistance in the circuit given below using superposition theorem.

Question Diagram

Q.4 Solve both questions :

Q4.1

State and explain Thevenin's Theorem. Show the Thevenin's equivalent representation of any circuit.

Q4.2

For the circuit given below, determine the current flowing through the 4 ohm resistance by Thevenin's theorem. What are the values of Thevenin's resistance and Thevenin's voltage for this circuit.

Question Diagram

Q.5 Solve both questions :

Q5.1

Calculate the Laplace Transform of the function $ f(t)=e^{-t}\sin(wt) $.

Q5.2

Define Gate function? Using Gate function find out the Laplace Transform of a single Sine wave.

Question Diagram

Q.6 Solve both questions :

Q6.1

Calculate the impedance, resistance, Power and power factor of a circuit whose expression for voltage and current are given by: $ V = 100\sin(wt+60^{\circ}) - 50\sin(5wt-30^{\circ}) \text{ volt} $ and $ I = 10\sin(wt+60^{\circ}) - 5\sin(3wt+30^{\circ}) \text{ amp} $.

Q6.2

A 400 mH coil of zero resistance is connected to an AC circuit in which 6 mA current is flowing. Find out the voltage across the coil if the frequency is 100 Hz.

Q.7 Solve this question :

Q7.1

Obtain the Y & Z parameters of the network shown below. Write the unit of all individual parameters.

Question Diagram

Q.8 Solve both questions :

Q8.1

Explain frequency response. Why magnitude and phase plots are necessary for frequency response analysis.

Q8.2

What is Q-factor? Calculate the quality factor of a series RLC circuit with $ L=2H $, $ C=2\mu F $ and $ R=20 \Omega $.

Q.9 Write short notes on any two of the following:


2022 100306

B.Tech 3rd Semester Examination, 2022

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer of the following (Any seven question only):

Q1.1

A 10 mH inductor carries a sinusoidal current of 1 A r.m.s at a frequency of 50 Hz. The average power dissipated by the inductor is

a)

0 W

b)

0.25 W

c)

0.5 W

d)

1.0 W

Q1.2

Thevenin's equivalent circuit consists of

a)

current source and series impedance

b)

voltage source and series impedance

c)

voltage source and shunt impedance

d)

current source and shunt impedance

Q1.3

When the two quantities are in quadrature, the phase angle between them will be.

a)

4545^{\circ}

b)

9090^{\circ}

c)

135135^{\circ}

d)

6060^{\circ}

Q1.4

A two-port network is symmetrical if

a)

Z11Z22Z12Z21=1Z_{11}Z_{22}-Z_{12}Z_{21}=1

b)

h11h22h12h21=1h_{11}h_{22}-h_{12}h_{21}=1

c)

ADBC=1AD-BC=1

d)

Y11Y22Y12Y21=1Y_{11}Y_{22}-Y_{12}Y_{21}=1

Q1.5

A two element series circuit is connected across an AC source given by $ e=200\sqrt{2}\sin(314t+20)V $, the current is found to be $ i=10\sqrt{2}\cos(314t-25)A $. The parameters of the circuit are

a)

R=20ΩR=20\Omega and C=160μFC=160\mu F

b)

R=14.14ΩR=14.14\Omega and C=225μFC=225\mu F

c)

L=45mHL=45mH and C=225μFC=225\mu F

d)

L=45mHL=45mH and C=160μFC=160\mu F

Q1.6

Superposition theorem is not applicable to networks containing

a)

nonlinear elements

b)

dependent voltage source

c)

dependent current source

d)

transformers

Q1.7

Which of the following is the Passive elements?

a)

Ideal current source

b)

Ideal voltage source

c)

Capacitor

d)

All of these

Q1.8

When a unit impulse voltage is applied to an inductor of 1 H, the energy supplied by the source is

a)

2 J

b)

1 J

c)

1/2 J

d)

1/4 J

Q1.9

There are no transients in pure resistance circuits because they

a)

Offer high resistance

b)

obey Ohm's law

c)

have no stored energy

d)

are linear circuits

Q1.10

When a number of two-port network is cascaded, then

a)

Z-parameters are added up

b)

Y-parameters are added up

c)

h-parameters are multiplied

d)

ABCD- parameters are multiplied

Q.2 Solve :

Q2.1

Two mutually coupled identical coils are connected in series having self-inductance $ L=4 \text{ mH} $ and mutual inductance $ M=2 \text{ mH} $.
What are the maximum and minimum possible values of equivalent inductances?

Determine the coefficient of coupling between the coils.

Q.3 Solve both questions :

Q3.1

Prove that the average power in an AC circuit is given by $ W=VI\cos\phi $, where symbols have their usual meanings.

Q3.2

A voltage of $ e(t)=150\sin(1000t) $ is applied across a series R-L-C circuit, where $ R=40\Omega $, $ L=0.13 \text{ H} $ and $ C=10\mu F $. (i) Compute the r.m.s value of the steady-state current. (ii) Find the r.m.s voltage across the inductor. (iii) Find the r.m.s voltage across the capacitor. (iv) Determine the active and reactive power supplied by the source.

Q.4 Solve all questions :

Q4.1

Find the Laplace transform of $ f(t)=e^{-at}\cos(\omega t) $, $ a>0 $.

Q4.2

Calculate the inverse Laplace transform of $ F(s)=\frac{1}{s(s^{2}-a^{2})} $.

Q4.3

In the series R-C circuit, the capacitor has an initial charge 2.5 mC. At $ t=0 $, the switch is closed and a constant voltage source $ V=100 \text{ V} $ is applied. Use the Laplace transform method to find the current in the circuit after closing the switch.

Q.5 Solve both questions :

Q5.1

Two impedances $ Z_{1}=40\angle 30^{\circ} $ and $ Z_{2}=30\angle 60^{\circ} \Omega $ are connected in series across a single-phase 230 V, 50 Hz supply. Calculate the (i) Current drawn (ii) pf, and (iii) power consumed by the circuit.

Q5.2

State and explain the Super Position Theorem and find out the step to be followed in super position theorem.

Q.6 Solve both questions :

Q6.1

State maximum power transfer theorem. Prove that efficiency of the circuit under maximum power transfer condition is 50%.

Q6.2

Draw the Thevenin equivalent circuit of the figure shown below and hence find the current through $ R=2\Omega $.

Question Diagram

Q.7 Solve both questions :

Q7.1

Find the current in a series RL circuit having $ R=2\Omega $ and $ L=10H $ while a d.c voltage of 100v is applied. What is the value of this current after 5 secs of switching on?

Q7.2

A steady state condition is reached with 100v d.c source. At $ t=0 $, switch K is suddenly open. Find the expression of current through the inductor after $ t=0.5 \text{ sec} $.

Question Diagram

Q.8 Solve all questions :

Q8.1

Define apparent power and Reactive power.

Q8.2

The current in a circuit lag the voltage by $ 30^{\circ} $ if the power be 400 w and the supply voltage be $ v=100\sin(377t+10^{\circ}) $ find complex power.

Q8.3

In an ac circuit $ v=100\sin(wt+30^{\circ})V $, $ I=5\sin(wt-30^{\circ})A $. find apparent power, real power and reactive power.

Q.9 Write short notes on the following:

Q9.1
a)

Reciprocity Theorem

b)

Laplace Theorem

c)

Two port network

d)

Resonance


2022 V4 100306

B.Tech 3rd Semester Examination, 2022

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer of the following (Any seven question only):

Q1.1

A 10 mH inductor carries a sinusoidal current of 1 A r.m.s at a frequency of 50 Hz. The average power dissipated by the inductor is

a)

0 W

b)

0.25 W

c)

0.5 W

d)

1.0 W

Q1.2

Thevenin's equivalent circuit consists of

a)

current source and series impedance

b)

voltage source and series impedance

c)

voltage source and shunt impedance

d)

current source and shunt impedance

Q1.3

When the two quantities are in quadrature, the phase angle between them will be.

a)

4545^{\circ}

b)

9090^{\circ}

c)

135135^{\circ}

d)

6060^{\circ}

Q1.4

A two-port network is symmetrical if

a)

Z11Z22Z12Z21=1Z_{11}Z_{22}-Z_{12}Z_{21}=1

b)

h11h22h12h21=1h_{11}h_{22}-h_{12}h_{21}=1

c)

ADBC=1AD-BC=1

d)

Y11Y22Y12Y21=1Y_{11}Y_{22}-Y_{12}Y_{21}=1

Q1.5

A two element series circuit is connected across an AC source given by $ e=200\sqrt{2}\sin(314t+20)V $, the current is found to be $ i=10\sqrt{2}\cos(314t-25)A $. The parameters of the circuit are

a)

R=20ΩR=20\Omega and C=160μFC=160\mu F

b)

R=14.14ΩR=14.14\Omega and C=225μFC=225\mu F

c)

L=45mHL=45mH and C=225μFC=225\mu F

d)

L=45mHL=45mH and C=160μFC=160\mu F

Q1.6

Superposition theorem is not applicable to networks containing

a)

nonlinear elements

b)

dependent voltage source

c)

dependent current source

d)

transformers

Q1.7

Which of the following is the Passive elements?

a)

Ideal current source

b)

Ideal voltage source

c)

Capacitor

d)

All of these

Q1.8

When a unit impulse voltage is applied to an inductor of 1 H, the energy supplied by the source is

a)

2 J

b)

1 J

c)

1/2 J

d)

1/4 J

Q1.9

There are no transients in pure resistance circuits because they

a)

Offer high resistance

b)

obey Ohm's law

c)

have no stored energy

d)

are linear circuits

Q1.10

When a number of two-port network is cascaded, then

a)

Z-parameters are added up

b)

Y-parameters are added up

c)

h-parameters are multiplied

d)

ABCD- parameters are multiplied

Q.2 Solve :

Q2.1

Two mutually coupled identical coils are connected in series having self-inductance $ L=4 \text{ mH} $ and mutual inductance $ M=2 \text{ mH} $.
What are the maximum and minimum possible values of equivalent inductances?

Determine the coefficient of coupling between the coils.

Q.3 Solve both questions :

Q3.1

Prove that the average power in an AC circuit is given by $ W=VI\cos\phi $, where symbols have their usual meanings.

Q3.2

A voltage of $ e(t)=150\sin(1000t) $ is applied across a series R-L-C circuit, where $ R=40\Omega $, $ L=0.13 \text{ H} $ and $ C=10\mu F $. (i) Compute the r.m.s value of the steady-state current. (ii) Find the r.m.s voltage across the inductor. (iii) Find the r.m.s voltage across the capacitor. (iv) Determine the active and reactive power supplied by the source.

Q.4 Solve all questions :

Q4.1

Find the Laplace transform of $ f(t)=e^{-at}\cos(\omega t) $, $ a>0 $.

Q4.2

Calculate the inverse Laplace transform of $ F(s)=\frac{1}{s(s^{2}-a^{2})} $.

Q4.3

In the series R-C circuit, the capacitor has an initial charge 2.5 mC. At $ t=0 $, the switch is closed and a constant voltage source $ V=100 \text{ V} $ is applied. Use the Laplace transform method to find the current in the circuit after closing the switch.

Q.5 Solve both questions :

Q5.1

Two impedances $ Z_{1}=40\angle 30^{\circ} $ and $ Z_{2}=30\angle 60^{\circ} \Omega $ are connected in series across a single-phase 230 V, 50 Hz supply. Calculate the (i) Current drawn (ii) pf, and (iii) power consumed by the circuit.

Q5.2

State and explain the Super Position Theorem and find out the step to be followed in super position theorem.

Q.6 Solve both questions :

Q6.1

State maximum power transfer theorem. Prove that efficiency of the circuit under maximum power transfer condition is 50%.

Q6.2

Draw the Thevenin equivalent circuit of the figure shown below and hence find the current through $ R=2\Omega $.

Question Diagram

Q.7 Solve both questions :

Q7.1

Find the current in a series RL circuit having $ R=2\Omega $ and $ L=10H $ while a d.c voltage of 100v is applied. What is the value of this current after 5 secs of switching on?

Q7.2

A steady state condition is reached with 100v d.c source. At $ t=0 $, switch K is suddenly open. Find the expression of current through the inductor after $ t=0.5 \text{ sec} $.

Question Diagram

Q.8 Solve all questions :

Q8.1

Define apparent power and Reactive power.

Q8.2

The current in a circuit lag the voltage by $ 30^{\circ} $ if the power be 400 w and the supply voltage be $ v=100\sin(377t+10^{\circ}) $ find complex power.

Q8.3

In an ac circuit $ v=100\sin(wt+30^{\circ})V $, $ I=5\sin(wt-30^{\circ})A $. find apparent power, real power and reactive power.

Q.9 Write short notes on the following:


2021 100306

B. Tech 3rd Semester Exam., 2021

Time 3 hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

  1. Choose the correct answer of the following (any seven):

Q1.a

The voltage across a 1.1-kW toaster that produces a current of 10 A is

a)

11 kV

b)

1100 V

c)

110 V

d)

11 V

Q1.b

The current II in the following circuit is

a)

0.8 A

b)

-0.2 A

c)

0.2 A

d)

-0.8 A

Q1.c

The current through a branch in a linear network is 2 A when the input source voltage is 10 V. If the voltage is reduced to 1 V and the polarity is reversed, the current through the branch is

a)

-2 A

b)

-0.2 A

c)

0.2 A

d)

2 A

Q1.d

A load is connected to a network. At the terminals to which the load is connected, Rth=10 ΩR_{th} = 10\ \Omega and Vth=20 VV_{th} = 20\text{ V}. The maximum possible power supplied to the load is

a)

160 W

b)

80 W

c)

40 W

d)

1 W

Q1.e

If a two-port is reciprocal, which of the following is not true?

a)

Z21=Z12Z_{21} = Z_{12}

b)

y21=y12y_{21} = y_{12}

c)

h21=h12h_{21} = h_{12}

d)

AD=BC+1AD = BC + 1

Q1.f

For the three coupled coils in the following figure, calculate the total inductance:

a)

10 H

b)

12 H

c)

38 H

d)

24 H

Q1.g

A network which contains one or more source of e.m.f. is known as

a)

linear network

b)

non-linear network

c)

passive network

d)

active network

Q1.h

The circuit having some properties for either direction of current is known as ___ circuit.

a)

bilateral

b)

unilateral

c)

irreversible

d)

reversible

Q1.i

Which of the following theorems can be applied to linear, non-linear, active, passive, time-variant, time-invariant, all kinds of circuits?

a)

Thevenin theorem

b)

Norton theorem

c)

Tellegen theorem

d)

Superposition theorem

Q1.j

Ideal current source has

a)

zero internal resistance

b)

infinite internal resistance

c)

low value of voltage

d)

large value of current

  1. Using nodal analysis, find IoI_o and VoV_o in the following circuit :

Q2

Using nodal analysis, find IoI_o and VoV_o in the following circuit :

  1. Apply mesh analysis to find ii in the following figure :

Q3

Apply mesh analysis to find ii in the following figure :

Q4.a

(i) In the following circuit, calculate VoV_o and IoI_o when Vs=1 VV_s = 1\text{ V}. (ii) Find VoV_o and IoI_o when Vs=10 VV_s = 10\text{ V}. (iii) What are VoV_o and IoI_o when each of the 1 Ω1\ \Omega resistors is replaced by a 10 Ω10\ \Omega resistor and V=10 VV = 10\text{ V}?

Q4.b

What do you understand by resonance? For a series RLCR-L-C circuit, derive the formula for (i) resonance frequency and (ii) cut-off frequency.

Q5.a

Explain the pole zero concept. How does this concept provide the knowledge of a stable system?

Q5.b

Use the superposition principle to find VoV_o and IoI_o in the circuit below:

  1. Determine RthR_{th} and VthV_{th} at terminals 1-2 of each of the circuits drawn below :

Q6

Determine RthR_{th} and VthV_{th} at terminals 1-2 of each of the circuits drawn below :

Q7.a

State and describe maximum power transfer theorem with a suitable example.

Q7.b

Compute the value of RR for which maximum power transfer can be offered to 10 Ω10\ \Omega resistor in the following figure. Also find the maximum power that can be transferred.

Q8.a

Find vo(t)v_o(t), using Laplace transform. Consider initial conditions to be zero. (i) If the switch in the circuit below, has been opened for a long time and is closed at t=0t = 0. (ii) Suppose that the switch has been closed for a long time and is opened at t=0t = 0.

Q8.b

Determine the step response Vo(t)V_o(t) to Vs=9u(t) VV_s = 9u(t)\text{ V} in the following circuit without using Laplace transform.

  1. For the bridge circuit in the following figure, obtain—

Q9

For the bridge circuit in the following figure, obtain— (i) the $z$-parameters; (ii) the $h$-parameters; (iii) the transmission parameters using the parameters obtained in parts (i) and (ii) separately. Compare the results obtained.


2020 100306 (PCC-EEE-01)

B.Tech 3rd Semester Special Exam., 2020

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Answer any seven questions of the following:

Q1.1

Find the current I in the circuit of Fig. 1 by using the superposition theorem. [DIAGRAM INSTRUCTION: A circuit with a 1A upward current source, a parallel 4 ohm resistor, followed by a T-network (1 ohm, 2 ohm, 3 ohm) and a 1V DC source.]

Question Diagram
Q1.2

In Fig. 2, find the value of $ R_{Th} $ and $ I_{SC} $.

Question Diagram
Q1.3

Find the value of $ R_{L} $ of Fig. 3 so that the maximum power can be transferred. [DIAGRAM INSTRUCTION: A circuit with two DC sources and an independent 1A current source, mixed with 10 ohm resistors, ending in load resistor RL.]

Question Diagram
Q1.4

Find the Z-parameters of the two-port network shown in Fig. 4.

Question Diagram
Q1.5

Two coupled coils have self-inductances $ L_{1}=50 \text{ mH} $ and $ L_{2}=200 \text{ mH} $ and a coefficient of coupling $ k=0.5 $. If coil 2 has 1000 turns, and $ i_{1}=5.0\sin(400t)\text{A} $, find the voltage at coil 2.

Q1.6

four 2-mark questions are missing

Q.2 Solve all questions :

Q2.1

Use the superposition theorem in the circuit shown in Fig. 7 to find current I. [DIAGRAM INSTRUCTION: A 10V DC source connected to a 5 ohm resistor, a dependent voltage source $ 2V_{x} $, a shunt 2 ohm resistor (with voltage $ V_{x} $), and a 2A independent current source.]

Question Diagram
Q2.2

Draw the Thévenin's equivalent circuit of Fig. 8 and hence find the current through $ R=2\Omega $. (All the resistances shown in the figure are in ohm).

Question Diagram
Q2.3

State compensation theorem.

Q.3 Solve all questions :

Q3.1

Find the current $ I_{0} $ of Fig. 9 using the superposition theorem.

Question Diagram
Q3.2

In the circuit of Fig. 10, find the effective value of the resistance seen by the source $ V_{s} $.

Question Diagram
Q3.3

Define incidence matrix. Find the complete incidence matrix of the graph shown in Fig. 11.

Question Diagram

Q.4 Solve all questions :

Q4.1

Define the g-parameters of an electrical circuit.

Q4.2

Find the g-parameters in the circuit shown in Fig. 12.

Question Diagram
Q4.3

Find the Z-parameters and Y-parameters of the circuit shown in Fig. 13.

Question Diagram

Q.5 Solve all questions :

Q5.1

Find the Laplace transform of $ f(t)=e^{-\alpha t}\cos(\omega t) $, $ \alpha>0 $.

Q5.2

Calculate the inverse Laplace transform of $ F(s)=\frac{1}{s(s^{2}-a^{2})} $.

Q5.3

In the series R-C circuit, the capacitor has an initial charge 2.5 mC. At $ t=0 $, the switch is closed and a constant-voltage source $ V=100\text{ V} $ is applied. Use the Laplace transform method to find the current in the circuit after closing the switch.

Q.6 Solve all questions :

Q6.1

Draw the graph for the given incidence matrix:
$ [A] = \begin{bmatrix} -1 & 0 & 0 & 1 & 0 & 1 & 0 \\ 0 & -1 & 0 & 0 & 0 & -1 & 1 \\ 0 & 0 & -1 & 0 & -1 & 0 & -1 \\ 0 & 0 & 0 & 0 & -1 & 0 & 0 \\ 1 & 1 & 1 & 1 & 0 & 0 & 0 \end{bmatrix} $

Q6.2

Find the cut-set matrix from the graph as shown in Fig. 14.

Question Diagram
Q6.3

Consider the network shown in Fig. 15, draw the graph and determine (i) number of links, (ii) rank of the graph and (iii) total number of trees.

Question Diagram

Q.7 Solve all questions :

Q7.1

State the characteristics of an ideal transformer.

Q7.2

Define r.m.s. value, form factor, peak factor, complex power and half power frequency.

Q7.3

Calculate the resonant frequency of a series R-L-C circuit.

Q7.4

Obtain the current in each branch of the network shown in Fig. 16, using the mesh current method.

Question Diagram

Q.8 Solve all questions :

Q8.1

Obtain the total power supplied by the 60 V source and the power absorbed in each resistor in the network of Fig. 17.

Question Diagram
Q8.2

Compute the mesh currents of Fig. 18.

Question Diagram
Q8.3

Define supermesh and supernode.

Q.9 Solve all questions :

Q9.1

Derive step response of a series R-C circuit.

Q9.2

Define forced response and natural response.

Q9.3

For the circuit shown in Fig. 19, the switch K is moved from position 1 to position 2 at $ t=0 \text{ s} $. Find the current $ i(t) $ assuming $ i(0_{-})=2\text{ A} $ and $ V_{c}(0_{+})=2\text{ V} $.

Question Diagram

2020 SPECIAL 100306 (PCC-EEE-01)

B.Tech 3rd Semester Special Exam., 2020

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Answer any seven questions of the following:

Q1.1

Find the current I in the circuit of Fig. 1 by using the superposition theorem. [DIAGRAM INSTRUCTION: A circuit with a 1A upward current source, a parallel 4 ohm resistor, followed by a T-network (1 ohm, 2 ohm, 3 ohm) and a 1V DC source.]

Question Diagram
Q1.2

In Fig. 2, find the value of $ R_{Th} $ and $ I_{SC} $.

Question Diagram
Q1.3

Find the value of $ R_{L} $ of Fig. 3 so that the maximum power can be transferred. [DIAGRAM INSTRUCTION: A circuit with two DC sources and an independent 1A current source, mixed with 10 ohm resistors, ending in load resistor RL.]

Question Diagram
Q1.4

Find the Z-parameters of the two-port network shown in Fig. 4.

Question Diagram
Q1.5

Two coupled coils have self-inductances $ L_{1}=50 \text{ mH} $ and $ L_{2}=200 \text{ mH} $ and a coefficient of coupling $ k=0.5 $. If coil 2 has 1000 turns, and $ i_{1}=5.0\sin(400t)\text{A} $, find the voltage at coil 2.

Q1.6

four 2-mark questions are missing

Q.2 Solve all questions :

Q2.1

Use the superposition theorem in the circuit shown in Fig. 7 to find current I. [DIAGRAM INSTRUCTION: A 10V DC source connected to a 5 ohm resistor, a dependent voltage source $ 2V_{x} $, a shunt 2 ohm resistor (with voltage $ V_{x} $), and a 2A independent current source.]

Question Diagram
Q2.2

Draw the Thévenin's equivalent circuit of Fig. 8 and hence find the current through $ R=2\Omega $. (All the resistances shown in the figure are in ohm).

Question Diagram
Q2.3

State compensation theorem.

Q.3 Solve all questions :

Q3.1

Find the current $ I_{0} $ of Fig. 9 using the superposition theorem.

Question Diagram
Q3.2

In the circuit of Fig. 10, find the effective value of the resistance seen by the source $ V_{s} $.

Question Diagram
Q3.3

Define incidence matrix. Find the complete incidence matrix of the graph shown in Fig. 11.

Question Diagram

Q.4 Solve all questions :

Q4.1

Define the g-parameters of an electrical circuit.

Q4.2

Find the g-parameters in the circuit shown in Fig. 12.

Question Diagram
Q4.3

Find the Z-parameters and Y-parameters of the circuit shown in Fig. 13.

Question Diagram

Q.5 Solve all questions :

Q5.1

Find the Laplace transform of $ f(t)=e^{-\alpha t}\cos(\omega t) $, $ \alpha>0 $.

Q5.2

Calculate the inverse Laplace transform of $ F(s)=\frac{1}{s(s^{2}-a^{2})} $.

Q5.3

In the series R-C circuit, the capacitor has an initial charge 2.5 mC. At $ t=0 $, the switch is closed and a constant-voltage source $ V=100\text{ V} $ is applied. Use the Laplace transform method to find the current in the circuit after closing the switch.

Q.6 Solve all questions :

Q6.1

Draw the graph for the given incidence matrix:
$ [A] = \begin{bmatrix} -1 & 0 & 0 & 1 & 0 & 1 & 0 \\ 0 & -1 & 0 & 0 & 0 & -1 & 1 \\ 0 & 0 & -1 & 0 & -1 & 0 & -1 \\ 0 & 0 & 0 & 0 & -1 & 0 & 0 \\ 1 & 1 & 1 & 1 & 0 & 0 & 0 \end{bmatrix} $

Q6.2

Find the cut-set matrix from the graph as shown in Fig. 14.

Question Diagram
Q6.3

Consider the network shown in Fig. 15, draw the graph and determine (i) number of links, (ii) rank of the graph and (iii) total number of trees.

Question Diagram

Q.7 Solve all questions :

Q7.1

State the characteristics of an ideal transformer.

Q7.2

Define r.m.s. value, form factor, peak factor, complex power and half power frequency.

Q7.3

Calculate the resonant frequency of a series R-L-C circuit.

Q7.4

Obtain the current in each branch of the network shown in Fig. 16, using the mesh current method.

Question Diagram

Q.8 Solve all questions :

Q8.1

Obtain the total power supplied by the 60 V source and the power absorbed in each resistor in the network of Fig. 17.

Question Diagram
Q8.2

Compute the mesh currents of Fig. 18.

Question Diagram
Q8.3

Define supermesh and supernode.

Q.9 Solve all questions :

Q9.1

Derive step response of a series R-C circuit.

Q9.2

Define forced response and natural response.

Q9.3

For the circuit shown in Fig. 19, the switch K is moved from position 1 to position 2 at $ t=0 \text{ s} $. Find the current $ i(t) $ assuming $ i(0_{-})=2\text{ A} $ and $ V_{c}(0_{+})=2\text{ V} $.

Question Diagram

2020 100306

B.Tech 3rd Semester Examination, 2020

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer of the following (any seven):

Q1.1

The Norton's equivalent of the circuit shown in figure below is

Question Diagram
a)

IN=5/2 AI_{N}=5/2 \text{ A} and RN=2ΩR_{N}=2\Omega

b)

IN=4/5 AI_{N}=4/5 \text{ A} and RN=1ΩR_{N}=1\Omega

c)

IN=2/5 AI_{N}=2/5 \text{ A} and RN=1ΩR_{N}=1\Omega

d)

IN=2/5 AI_{N}=2/5 \text{ A} and RN=2ΩR_{N}=2\Omega

Q1.2

A 10 mH inductor carries a sinusoidal current of 1 A r.m.s. at a frequency of 50 Hz. The average power dissipated by the inductor is

a)

0 W

b)

0.25 W

c)

0.5 W

d)

1.0 W

Q1.3

Thevenin's equivalent circuit consists of

a)

current source and series impedance

b)

voltage source and series impedance

c)

voltage source and shunt impedance

d)

current source and shunt impedance

Q1.4

A two-element series circuit is connected across an AC source given by $ e=200\sqrt{2}\sin(314t+20) \text{ V} $. The current is found to be $ i=10\sqrt{2}\cos(314t-25) \text{ A} $. Then parameters of the circuit are

a)

R=20ΩR=20\Omega and C=160μFC=160\mu F

b)

R=14.14ΩR=14.14\Omega and C=225μFC=225\mu F

c)

L=45 mHL=45\text{ mH} and C=225μFC=225\mu F

d)

L=45 mHL=45\text{ mH} and C=160μFC=160\mu F

Q1.5

There are no transients in pure resistance circuits because they

a)

offer high resistance

b)

obey Ohm's law

c)

have no stored energy

d)

are linear circuits

Q1.6

In the below network, the switch K is opened at $ t=0 $. Then $ \frac{dV}{dt} $ at $ t=0^{+} $ is

Question Diagram
a)

1000 V/sec

b)

100 V/sec

c)

10 V/sec

d)

1 V/sec

Q1.7

When a number of two-port network is cascaded, then

a)

Z-parameters are added up

b)

Y-parameters are added up

c)

h-parameters are multiplied

d)

ABCD-parameters are multiplied

Q1.8

Two coils are coupled in such a way that the mutual inductance between them is 16 mH. If the inductances of the coils are 20 mH and 80 mH respectively, the coefficient of coupling is

a)

0.01

b)

0.4

c)

0.1

d)

0.0025

Q1.9

When a unit impulse voltage is applied to an inductor of 1 H, the energy supplied by the source is

a)

2 J

b)

1 J

c)

1/2 J

d)

1/4 J

Q1.10

The h-parameters $ h_{11} $ and $ h_{22} $ are related to Z and Y-parameters as

a)

h11=Z11h_{11}=Z_{11} and h22=1/Z22h_{22}=1/Z_{22}

b)

h11=Z11h_{11}=Z_{11} and h22=Y22h_{22}=Y_{22}

c)

h11=1/Y11h_{11}=1/Y_{11} and h22=1/Z22h_{22}=1/Z_{22}

d)

h11=1/Y11h_{11}=1/Y_{11} and h22=Y22h_{22}=Y_{22}

Q.2 Solve :

Q2.1

Two mutually coupled identical coils are connected in series having self-inductance $ L=4 \text{ mH} $ and mutual inductance $ M=2 \text{ mH} $.
What are the maximum and minimum possible values of equivalent inductances?

Determine the coefficient of coupling between the coils.

Q.3 Solve both questions :

Q3.1

Show that Thevenin's and Norton's theorems are dual to each other.

Q3.2

Using Norton's theorem, find the current in $ 5\Omega $ resistor for the circuit shown below.

Question Diagram

Q.4 Solve both questions :

Q4.1

When can a two-port circuit be declared as a reciprocal circuit?

Q4.2

Find ABCD parameters for the two-port network shown in the figure below:

Question Diagram

Q.5 Solve both questions :

Q5.1

Prove that the average power in an AC circuit is given by $ W=VI\cos\phi $, where symbols have their usual meanings.

Q5.2

A voltage of $ e(t)=150\sin(1000t) $ is applied across a series R-L-C circuit, where $ R=40\Omega $, $ L=0.13 \text{ H} $ and $ C=10\mu\text{F} $. (i) Compute the r.m.s. value of the steady-state current. (ii) Find the r.m.s. voltage across the inductor. (iii) Find the r.m.s. voltage across the capacitor. (iv) Determine the active and reactive power supplied by the source.

Q.6 Solve this question :

Q6.1

Determine overall Z-parameters when two 2-port networks with identical $ Z_{11}=Z_{12}=Z_{21}=Z_{22}=2\Omega $ are connected in cascade.

Q.7 Solve this question :

Q7.1

In the R-L-C circuit shown in figure below, $ I_{s}=10 \text{ A} $, $ R=1\Omega $, $ L=1\text{H} $, $ C=1\mu\text{F} $ and $ i_{L}(0^{-})=0 $. Determine the following parameters after the switch is closed at $ t=0 $: (a) $ V(0^{+}) $ (b) $ \frac{dV}{dt} $ at $ t=0^{+} $ (c) $ \frac{d^{2}V}{dt^{2}} $ at $ t=0^{+} $.

Question Diagram

Q.8 Solve both questions :

Q8.1

An R-L-C tank circuit is composed of components having values as $ R=0.2\Omega $, $ L=100 \text{ mH} $ and $ C=50\mu\text{F} $. Determine the resonance frequency and the corresponding input current at 24 V.

Q8.2

Obtain the values of R, L and C in a series R-L-C circuit that resonates at 1.5 kHz and consumes 50 W from a 50 V a.c. source operating at the resonance frequency. The bandwidth is 0.75 kHz.

Q.9 Solve this question :

Q9.1

For the circuit shown below, obtain the current through the capacitor C at $ t=0^{+} $ using Laplace transform following the switching takes place at $ t=0 $. Assume the capacitor to be initially discharged.

Question Diagram

2020 V4 100306

B.Tech 3rd Semester Examination, 2020

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer of the following (any seven):

Q1.1

The Norton's equivalent of the circuit shown in figure below is

Question Diagram
a)

IN=5/2 AI_{N}=5/2 \text{ A} and RN=2ΩR_{N}=2\Omega

b)

IN=4/5 AI_{N}=4/5 \text{ A} and RN=1ΩR_{N}=1\Omega

c)

IN=2/5 AI_{N}=2/5 \text{ A} and RN=1ΩR_{N}=1\Omega

d)

IN=2/5 AI_{N}=2/5 \text{ A} and RN=2ΩR_{N}=2\Omega

Q1.2

A 10 mH inductor carries a sinusoidal current of 1 A r.m.s. at a frequency of 50 Hz. The average power dissipated by the inductor is

a)

0 W

b)

0.25 W

c)

0.5 W

d)

1.0 W

Q1.3

Thevenin's equivalent circuit consists of

a)

current source and series impedance

b)

voltage source and series impedance

c)

voltage source and shunt impedance

d)

current source and shunt impedance

Q1.4

A two-element series circuit is connected across an AC source given by $ e=200\sqrt{2}\sin(314t+20) \text{ V} $. The current is found to be $ i=10\sqrt{2}\cos(314t-25) \text{ A} $. Then parameters of the circuit are

a)

R=20ΩR=20\Omega and C=160μFC=160\mu F

b)

R=14.14ΩR=14.14\Omega and C=225μFC=225\mu F

c)

L=45 mHL=45\text{ mH} and C=225μFC=225\mu F

d)

L=45 mHL=45\text{ mH} and C=160μFC=160\mu F

Q1.5

There are no transients in pure resistance circuits because they

a)

offer high resistance

b)

obey Ohm's law

c)

have no stored energy

d)

are linear circuits

Q1.6

In the below network, the switch K is opened at $ t=0 $. Then $ \frac{dV}{dt} $ at $ t=0^{+} $ is

Question Diagram
a)

1000 V/sec

b)

100 V/sec

c)

10 V/sec

d)

1 V/sec

Q1.7

When a number of two-port network is cascaded, then

a)

Z-parameters are added up

b)

Y-parameters are added up

c)

h-parameters are multiplied

d)

ABCD-parameters are multiplied

Q1.8

Two coils are coupled in such a way that the mutual inductance between them is 16 mH. If the inductances of the coils are 20 mH and 80 mH respectively, the coefficient of coupling is

a)

0.01

b)

0.4

c)

0.1

d)

0.0025

Q1.9

When a unit impulse voltage is applied to an inductor of 1 H, the energy supplied by the source is

a)

2 J

b)

1 J

c)

1/2 J

d)

1/4 J

Q1.10

The h-parameters $ h_{11} $ and $ h_{22} $ are related to Z and Y-parameters as

a)

h11=Z11h_{11}=Z_{11} and h22=1/Z22h_{22}=1/Z_{22}

b)

h11=Z11h_{11}=Z_{11} and h22=Y22h_{22}=Y_{22}

c)

h11=1/Y11h_{11}=1/Y_{11} and h22=1/Z22h_{22}=1/Z_{22}

d)

h11=1/Y11h_{11}=1/Y_{11} and h22=Y22h_{22}=Y_{22}

Q.2 Solve :

Q2.1

Two mutually coupled identical coils are connected in series having self-inductance $ L=4 \text{ mH} $ and mutual inductance $ M=2 \text{ mH} $.
What are the maximum and minimum possible values of equivalent inductances?

Determine the coefficient of coupling between the coils.

Q.3 Solve both questions :

Q3.1

Show that Thevenin's and Norton's theorems are dual to each other.

Q3.2

Using Norton's theorem, find the current in $ 5\Omega $ resistor for the circuit shown below.

Question Diagram

Q.4 Solve both questions :

Q4.1

When can a two-port circuit be declared as a reciprocal circuit?

Q4.2

Find ABCD parameters for the two-port network shown in the figure below:

Question Diagram

Q.5 Solve both questions :

Q5.1

Prove that the average power in an AC circuit is given by $ W=VI\cos\phi $, where symbols have their usual meanings.

Q5.2

A voltage of $ e(t)=150\sin(1000t) $ is applied across a series R-L-C circuit, where $ R=40\Omega $, $ L=0.13 \text{ H} $ and $ C=10\mu\text{F} $. (i) Compute the r.m.s. value of the steady-state current. (ii) Find the r.m.s. voltage across the inductor. (iii) Find the r.m.s. voltage across the capacitor. (iv) Determine the active and reactive power supplied by the source.

Q.6 Solve this question :

Q6.1

Determine overall Z-parameters when two 2-port networks with identical $ Z_{11}=Z_{12}=Z_{21}=Z_{22}=2\Omega $ are connected in cascade.

Q.7 Solve this question :

Q7.1

In the R-L-C circuit shown in figure below, $ I_{s}=10 \text{ A} $, $ R=1\Omega $, $ L=1\text{H} $, $ C=1\mu\text{F} $ and $ i_{L}(0^{-})=0 $. Determine the following parameters after the switch is closed at $ t=0 $: (a) $ V(0^{+}) $ (b) $ \frac{dV}{dt} $ at $ t=0^{+} $ (c) $ \frac{d^{2}V}{dt^{2}} $ at $ t=0^{+} $.

Question Diagram

Q.8 Solve both questions :

Q8.1

An R-L-C tank circuit is composed of components having values as $ R=0.2\Omega $, $ L=100 \text{ mH} $ and $ C=50\mu\text{F} $. Determine the resonance frequency and the corresponding input current at 24 V.

Q8.2

Obtain the values of R, L and C in a series R-L-C circuit that resonates at 1.5 kHz and consumes 50 W from a 50 V a.c. source operating at the resonance frequency. The bandwidth is 0.75 kHz.

Q.9 Solve this question :

Q9.1

For the circuit shown below, obtain the current through the capacitor C at $ t=0^{+} $ using Laplace transform following the switching takes place at $ t=0 $. Assume the capacitor to be initially discharged.

Question Diagram

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