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circuit theory question bank for sbtet polytechnic
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CIRCUIT THEORY QUESTION BANK
UNIT 1
SHORT ANSWER QUESTIONS: (3 MARKS)
1. Distinguish between active and passive elements. [Oct/Nov2006, 2009, 2010, 2012April/May2012]
2. State the basic differences between AC and DC.
[Oct/Nov2007, 2009, 2010 April/May2011, March/April2013]
3. Explain phase difference with waveforms. [Oct/Nov2006, 2010, April/May2012, March/April2008]
4. Define RMS value and phase difference. [Oct/Nov2011]
5. Define average value and RMS value. [March/April2008]
6. Define peak value and instantaneous value. [Oct/Nov2008]
7. Define the term resonance. [Oct/Nov2007]
8. What is resonance? Derive the expression for series resonance of RLC circuit. [Oct/Nov2010]
9. Define half power frequencies, bandwidth of a resonant circuit. [March/April2004, Oct/Nov2009]
10. Define bandwidth and selectivity of a resonant circuit. [March2002, 2003, 2008, Oct2006]
11. Define Q-Factor of a coil and capacitor circuits. [Oct/Nov2008]
12. Draw the frequency versus current for series RLC resonant circuit. [April/May2011]
13. List the applications of resonance. [March/April2013]
14. What is the capacitance of a capacitor if the charging current of 100mA flows, when 40V voltage is
applied at a frequency of 50Hz? [Oct/Nov2012, March/April2013]
15. The reactance of a coil at 100Hz is 20Ω. What is its reactance at 1 KHz? [Oct/Nov2012]
16. The current in a coil changes from 20A to 12A in 0.1s. if the e.m.f produced is 100V, find the
inductance of the coil. [April/May2012]
17. Draw the waveforms for voltage and current in (a) pure inductor (b) pure capacitor. [March/April2009]
18. Define phase difference. Draw the waveform for voltage and current in a pure capacitor showing 900
phase angle. [Oct/Nov2010]
19. A sinusoidal voltage of 5KHz frequency is applied across a 10mH inductor. Determine the inductive
reactance. [April/May2011, March/April2013]
20. Find the resonate frequency ωofor the two branch parallel circuit shown in Fig [Sep/Oct2004]
21. In the parallel circuit shown in figure, find the resonant frequency f0. [Oct/Nov2005]
22. For the tank circuit shown below, find the resonant frequency. [April/May2011]
ESSAY QUESTIONS: (5 TO 10 MARKS)
1. Explain phase and phase difference with waveforms. [April/May2008, 2009,March/April2013]
2. Obtain the expression for current of a pure capacitor circuit with a.c source. [Oct/Nov2007, 2009]
3. Explain the phase difference between voltage across and current through a pure capacitor.
[April/May2011]
4. Derive the expression for instantaneous power of a pure inductor and pure capacitor with AC source.
[Oct/Nov2006,2011]
5. Obtain the expression for current of a series RC circuit applied with AC source and draw the phasor
diagram. [Oct/Nov2009]
6. Distinguish between series and parallel resonance.
[March2004, April2002, March/April2008, 2009, April/May2012, Oct/Nov2009, 2010, 2012]
7. Show that resonant frequency is the geometric mean of two half power frequencies in a series RLC
circuit. [Oct/Nov2008, 2011, 1997, March/April2003]
8. Mention the conditions for resonance of series resonant circuit. [April2002, Oct/Nov2008]
9. Derive expression for the resonant frequency of a series RLC circuit and write the expressions for
current and impedance at resonance. [Oct/Nov2012]
10. Derive the condition for resonance of parallel resonance circuit at all frequencies.
[April2002, Oct/Nov1997, March/April2008]
11. Define the term resonance. Mention the condition for resonance in a parallel resonance circuit.
[Oct/Nov1998, 2008]
12. Derive the expression for resonant frequency of RLC parallel circuit. [Oct/Nov2007]
13. Derive the expression for bandwidth of RLC series resonant circuit. [Oct/Nov2007, 2009, 2010]
14. Write the expression for current of a parallel RL circuit with AC source. [Oct/Nov2010]
15. Explain the V-I characteristics and power calculations of the parallel LC circuit with AC source.
[March2009, Oct2011]
16. Obtain the expression for current of a series LC circuit with AC source and sketch the voltage and
current waveforms. [March/April2013]
17. Explain the effect of resistance of resistance on bandwidth. [April/May2012]
18. Show the impedance =
at parallel resonance. [April/May2010, Oct2011]
19. Derive the expression for the resonant frequency of a series RLC circuit and write the expressions for
current and impedance at resonance. [Oct/Nov2012]
20. A 100Ω resistor is connected in series with an inductor across a sinusoidal 400V, 50Hz supply. If the
voltage across resistor and inductor are respectively 200V and 300V. Calculate: (1) inductance, L and
(2) phase angle ø [Oct/Nov2011]
21. A series RLC circuit with L=0.5H has an instantaneous voltage V=70.7sin (500t+300) volts and an
instantaneous current I =1.5sin (500t) amps. Find the values of R and C. At what frequency will the
circuit be resonant? [Oct/Nov2011]
22. A 30Ω resistor and a pure inductor of reactance of 40Ω are connected in series across a 200V AC
supply. Determine impedance, current and power factor of the circuit. [Oct/Nov2009]
23. An alternating e.m.f 100√2 sin314 is applied to the resistor of 20Ω. Determine (1) The current and
(2) The power. [April/May2011]
24. Determine the total impedance (Z), current (I), phase angle (ø), capacitive voltage (VC) and resistance
voltage (VR) in the figure. [August2009 unit test I]
25. A series RLC circuit consists of a capacitor of reactance 120Ω and a coil having resistance of 60Ω and
inductive reactance of 180Ω. The combination is connected across 200V, 50Hz supply. Calculate (1)
current (2) power factor (3) power taken by the circuit. [April/May2010]
26. A resistance of 100Ω, an inductance of 0.2H and a capacitor of 150µF are connected in series along
230V, 50Hz supply. Calculate the current drawn by the circuit, power factor of the circuit and power
consumed by the circuit. [March/April2009]
27. A current of 50∟-300A if flowing a circuit consists of series connected elements when excited by a
source of 230∟-450V, 50Hz. Determine the elements of the circuit. [Oct/Nov2008]
28. A series combination of 10Ω resistance and 50mH inductance is connected to a 220V, 50Hz supply.
Estimate the current and voltage across R and L and draw the phasor diagram. [March/April2008,2013]
29. A parallel RC circuit having R=50Ω, c=150µF is connected across 230V, 50Hz supply. Calculate (1)
total current (2) phase difference between voltage and current (3) power factor. [March/April2007]
30. A series parallel circuit consists of two parallel branches A and B are in series with branch C. The
impedances of the branches are ZA=10+j8, ZB=9-j6, and ZC=3+j2. The voltage applied to the circuit is
V=100V. Find the line current I, current through branch A (IA), current through branch B (IB), phase
angle between IA and IB and power factor of the circuit. [Oct/Nov2007]
31. A series RLC circuit with R=24Ω and L=0.6H results in a leading phase angle of 600 at a frequency of
40Hz. At what frequency with the circuit be resonant? [April/May1998, 2010, Oct2005]
32. A series RLC circuit with R=100Ω, L=0.5H and C=40µF has applied voltage of 100∟00V with variable
frequency. Calculate the resonant frequency, current at resonance, voltage across R, L and C. Also
calculate the Q-factor, upper and lower half power frequencies and bandwidth. [june1996]
33. In series RLC circuit, the voltage and current are given by V=353.5sin (3000t-100) volts, i=12.5sin
(3000t-550) amps and the inductance is 0.01H. Find R and C. [Oct/Nov2010]
34. Find the total current in the parallel LC circuit of L=0.05H and C=0.667µF with an applied voltage
V=200 sin5000t Volts. [April/May2011]
35. The parallel circuit shown in figure, is resonance when XC = 9.68 Ω . Find the total phasor current.
[Oct/Nov2005]
36. Find 'C’ which results in resonance for the circuit shown in figure, when w=5000 rad/sec.
[March/April2005]
37. Find the value of RL for which the parallel circuit shown in Fig., is resonant. [Oct/Nov2008]
38. What value o f Rc yields resonance in the parallel circuit shown in figure. [Oct/Nov2006]
39. Determine RL and RC which cause the circuit shown in figure below to be resonant at all frequencies.
[Oct/Nov2006]
40. For the circuit shown below, determine the total current, the phase angle and total impedance in the
circuit. [April/May2012]
UNIT 2
SHORT ANSWER QUESTIONS:
EACH QUESTION CARRIES 3 MARKS
1. Define mesh, node and branch of a network. [Oct/Nov2010, March/April2002, 2003, 2004]
2. Define junction and loop of a network. [Oct/Nov2010]
3. State ohms law and give its limitations. [Oct/Nov2010, 2007, March/April2008]
4. Mention the limitations of ohm’s law. [April/May2012]
5. State and explain Kirchhoff’s laws with examples. [Oct/Nov2007, March/April2009]
6. Define Kirchhoff’s laws? [Oct/Nov2011]
7. Give the star and delta circuits. [April2011, Oct/Nov2006]
8. Define driving point impedance and transfer impedance of a network.
[Oct/Nov2006, 2008, 2010, 2011 March/April2009, 2013, Sept/Oct2001]
9. Define driving point admittance and transfer admittance of a network.
[Jan2000, Oct/Nov2007, 2009, 2012, March/April2008, April/May2011, 2012]
10. Draw the equivalent circuits of star and delta connection. Also write the transformation formulae.
[Oct/Nov2006]
11. Give mathematical relations for star to delta transformation and delta to star transformation.
[Oct/Nov2009]
12. Determine the number of mesh currents required to solve the problem given below: [March/April2008, Oct/Nov2011]
13. Find the number of mesh equations required to solve the given network. [March/April2008]
14. How many mesh current equations are required for the following circuit? [Oct/Nov2007]
15. How many mesh current equations are required for the following circuit? [March/April2008]
16. How many mesh current equations are required for the following circuit? [March/April2004]
17. How many node voltage equations are required to solve the following circuits? [Sep/Oct.2004]
18. Write the mesh current equations for the following network shown.
19. Write the mesh equations required to solve the network shown below. [March/April2011]
20. Determine the number of mesh equations required to solve the network shown below:
[March/April2013]
21. Determine the number of node voltage equations required to solve the network shown below.
[Oct/Nov2012]
ESSAY QUESTIONS:
EACH QUESTION CARRIES 4 TO 10 MARKS DEPENDING UP ON THE QUESTION
1. Convert the given Delta into equivalent star. [March/April2009]
2. Draw the equivalent circuits of star and delta connection and also write the transformation formulae.
[April/May2011, March/April2013]
3. Convert the star network shown in the figure to an equivalent delta network. [Oct/Nov2012]
4. Obtain the star connected equivalent for the delta connected circuit shown in figure. [April/May2011]
5. Obtain the star connection of three impedances equivalent to the network CDE shown in Fig below and
find star equivalent ABC. [Oct/Nov2009, March/April2007, 2013]
6. For the circuit shown in Fig. below, find the equivalent star connected network. [March/April2008]
7. Write the mesh current equations for the given circuit shown below. [March/April2005]
8. Write the mesh current equations for the given network and arrange them in matrix form.
[March/April2004]
9. In the network shown in figure below.Write the mesh current equations and arrange them in matrix
form. [March/April2008]
10. Write the mesh current equations for the given network and arrange them in matrix form.[Oct/Nov2005]
11. Write the mesh current equations for the network shown Fig. and express them in a matrix form.
[Oct/Nov2009]
12. Write the mesh current equations for the circuit show figure below and determine the currents I1, I2 and
I3 [I UNIT TEST- AUGUST – 2009]
13. Determine the power absorbed by 5Ω resistor in the circuit shown in Fig. by using mesh analysis.
[Oct/Nov2007, April/May2012]
14. Find the voltage VAB by mesh current method. Apply cramer's rule. [March/April2008,2009]
15. Find the voltage VAB and VBC of the given network. [March,April2009, Sep/Oct.2004]
16. Find the power output of the voltage source in the circuit shown in Figure below. Also determine the
power in circuit resistors. [March,April2008, Sep/Oct.2004]
17. Find the voltage transfer function for the circuit shown in fig. [March/April2008]
18. Find the magnitude of the voltage source V 1 in the given network, which results in an effective voltage
of 20V across the 5Ω resistor using mesh current analysis. [March/April2007]
19. The network shown in Fig.contains two voltage sources V 1 and V2 with V1 =30∟0° V, determine V2 such that current in the (2 + J3) Ω impedance is zero. [Oct/Nov2011,2008,March/April2007,2005]
20. Solve the network shown in Fig. using mesh current analysis to find the current through the 3K ohm
resistor. [March/April2007]
21. For the network shown below write the mesh current equations in matrix form and determine the values
of the currents I1, I2 and I3. [March/April2006]
22. In the circuit shown in Fig. below. Find the currents IA, IB and IC. [Oct/Nov2006,March/April2004]
23. In the network shown in figure, use matrix methods determine the input impedance as seen by the 50V
source. Calculate I1 using this impedance. [Oct/Nov2009,March/April2004,2005]
24. For the following circuit determine the transfer impedances Z12, Z13. [March/April2009]
25. I n the network shown in figure, determine the impedances Z11 , Z12 and Z13. Using these impedances
find I 1 , I2, and I3. [Sep/Oct.2004]
26. Find the three currents I1, I2 and I3 using driving point impedance and transfer impedance for the
network shown in Fig. [April/May2010]
27. In the network shown in figure a below, find the current in the 5Ω resistor using mesh current analysis.
[Nov./Dec.2003]
28. Write the mesh current equations and arrange them in matrix form. [March/April2004]
29. In the network shown in Fig. below, find V2 such that the V2 source current will be zero. [Oct/Nov2006]
30. Write down the nodal equations and put them in the matrix form for the following circuit. [March2009]
Determine the voltage of the nodes 1 and 2 in the network of figure below, using input and transfer
admittances. [Oct/Nov2010]
31. Write node voltage equations for the network shown in fig. below and express them in the matrix form.
[ March/April2008]
32. Write the nodal equations for the network shown in fig. below and express them in the matrix form.
[Oct/Nov2008]
33. Determine the current in 2Ω resistor in the circuit shout in figure below by using nodal analysis.
[Oct/Nov2007]
34. For the circuit shown in Fig. below find the voltage VAB using node voltage analysis.
[March/April2007, Oct/Nov2006, Sep/Oct.2004, 2005]
35. For the circuit shown in Fig. below, determine the power output of the source and the power in each
resistor of the circuit using nodal analysis. [Oct/Nov2006, 2011]
36. In the circuit shown in figure below, determine output of the source and the power consumed in resistor
of the network using nodal analysis method. [ Oct/Nov2009]
37. I n the circuit shown in figure below, find the node voltage V1. [March/April2007, Oct/Nov2009]
38. In the network shown in figure below determine the voltage VAB [March/April2005]
39. In the network shown in Fig. below, determine the voltage VAB by the nodal method. [Oct/Nov2008]
40. Find the voltage transfer function Vo / Vi for the circuit shown in fig. [Oct/Nov2009]
41. Using nodal analysis, find the voltage transfer function for the network shown in Fig. below.
[Oct/Nov2008]
42. In the given network, find the node voltages V 1 and V2 . [ March/April2007]
43. Determine the voltages of node 1 and node 2 with respect to the network shown in figure below.
[March/April2008,2009]
44. Given the nodes 1 and 2 in the network of fig. shown below, find the ratio V1/V2
[Oct/Nov2008, March/April2005]
45. Determine the node voltages V1 and V2 in the network shown in figure below, us i ng i np u t a nd
t ra nsf e r admittances. [Oct/Nov2006, March/April2008]
46. Determine the voltages o f nodes 1 and 2 in the network shown in figure using input and transfer
admittance [Oct/Nov2008]
47. Find the voltage VAB in the network shown below using node voltage network analysis.
[March/April2006, 2013Nov/Dec.2003, April/May2010, 2011]
48. In the network shown in figure below, find the line currents IA, lB and Ic. [Oct/Nov2005]
49. For the circuit shown below find the voltage o f node 1. [Oct/Nov2005]
50.Determine the number of mesh equations required to solve the network given below:
[Oct. 2007]
51. For the following given circuit, find I by mesh current analysis.
52. For the following circuit find the currents IA, IB, IC?
53. For the network figure shown determine V2 such that the mesh current in the (2+j3)Ω impedance is zero
using mesh current analysis
54. Determine the voltages at 1 and 2 of the network shown below by using nodal analysis.
[April/May2012]
UNIT 3
SHORT ANSWER QUESTIONS: (3MARKS)
1. Explain ideal voltage source and ideal current source.
[Oct/Nov2008, 2011, 2012, March2008, April2010]
2. Convert ideal voltage source to ideal current source. [March/April2008]
3. State reciprocity theorem and mention its limitations. [March/April2005, 2002, Oct/Nov2010]
4. Mention the limitations of super position theorem. [Oct/Nov2012, 2009, 2010]
5. State Norton theorem. [March/April2005, 2008]
6. State and explain Norton theorem. [March/April1999, 2003, 2005,2008, Jan2000, April/May2010]
7. State and prove maximum power transfer theorem for resistive load.
[Sept/Oct2001, March/April2009, Oct/Nov2006]
8. State the Thevenin’s theorem and draw a Thevenin’s equivalent circuit.
9. State superposition theorem. [Oct/Nov2008]
10. State and explain Thevenin’s theorem.
11. How to convert thevenin’s equivalent circuit to norton’s equivalent circuit. [Oct/Nov2010]
12. List the advantages of super position theorem. [Oct/Nov2010]
13. Define maximum power transfer theorem for different loads. [Oct/Nov2010, 2011]
14. Explain source transformation techniques. [Oct/Nov2007]
15. Give the limitations of thevenin’s and norton’s theorems. [April/May2011, Oct/Nov2011]
16. What is the equivalent current source for a voltage source of 12V in series with 6Ω resistance?
[April/May2011]
17. Compare ideal voltage source and practical voltage source. [April/May2012]
18. Give the limitations of reciprocity theorem. [April/May2012]
19. A 16mA current source has an internal resistance of 10KΩ. how much current will flow in a 2.5KΩ load
connected across its terminals? [March/April2013]
20. List any three advantages of thevenin’s and norton’s theorems. [March/April2013]
ESSAY QUESTIONS: (5 TO 10 MARKS)
1. Convert the following current source into equivalent voltage source. [March/April2004]
2. Usi ng su per po si t i on t he or e m. F i nd t he c ur r e nt i n 15 o hms resistor. [Oct/Nov2009]
3. Find the current through 2k Ω resistor in the circuit show n i n F i g. usi ng superposition theorem.
[Oct/Nov2008]
4. Apply superposition theorem to the network shown in Fig. below and obtain the current in (3 + J4)ohm
impedance. [Oct/Nov2008]
5. For the circuit shown below, determine the current in (2+J3)ohm using super position theorem.
[Oct/Nov2011]
6. Apply the superposition theorem to the network shown in Fig. below and obtain the current in the
10ohm resistor. [Nov./Dec.2003]
7. In the given network find the current in 4ohm resistor using superposition theorem.
[Nov./Dec.2003, March/April2004,2006,2007]
8. Find the voltage across the 2ohm resistor by using superposition theorem, for the circuit shown in Fig.
below. [Oct/Nov2010, 2007]
9. Determine the Thevenin’s equivalent circuit across AB for the given circuit shown in fig.
[Aug Unit Test 2009]
10. Obtain the Thevenin equivalent circuit for the network shown in Fig. [March/April2006,2007]
11. Draw the Thevenin's equivalent network at AB for the network shown in Fig.
[Oct/nov2011, March/April2008, April/May2010]
12. Obtain the Thevenin's equivalent circuit for the network showing Fig. [March/April2007]
13. Obtain t he Thevenin's equivalent circuit for the active network shown in Fig. [Oct/Nov2009]
14. Obtain the Thevenin's equivalent circuit at terminals AB of the network shown in Fig. below.
[Oct/Nov2005]
15. Determine the current through ammeter o f 2ohm connected in the unbalanced wheat stone bridge using
Theveninn's theorem. [March/April 2009]
16. Obtain Thevenin's equivalent circuit for the bridge circuit shown in Fig.
[Oct./Nov.2010, Sep./Oct.2004]
17. Use Thevenin's theorem to calculate the power in the load of 10 ohm of the network shown in fig.
[March/April 2005]
18. Replace the active network shown in Fig.below with a Thevenin's equivalent at the terminals AB.
[Oct./Nov.1998]
19. The active network shown in Fig. contains a current source I = 5∟30° A. Find t he Thevenin equivalent
circuit at terminals AB. [Jan.2000]
20. Obtain the Norton's equivalent circuit with respect to terminals AB for the network shown in Fig.
[March/April 2008,Nov/Dec.2003]
21. Draw Norton's equivalent circuit for the given circuit shown in fig. [March/April 2008]
22. Obtain the Norton's equivalent circuit for the active network given in Fig. [Oct./Nov.2008]
23. Obtain the Norton’s equipment network at AB for the given network Fig. [Oct./Nov.2006]
24. Obtain norton’s equivalent network at AB for network shown below: [March/April2013]
25. Find the Norton's equipment circuit at terminals AB of the network shown in Fig. [March/April 2008]
26. Find the Norton's equipment at the terminals AB for the network shown in Fig.
[March/April 2004, Oct./Nov.2008]
27. Obtain the Norton's equivalent circuit for the network shown Fig. [Oct./Nov.2006]
28. Obtain Norton's equivalent circuit for the network shown in Fig. [Oct./Nov.2006]
29. Obtain Notion's equivalent circuit at AB terminals for the circuit given below. [April/May 2002, 2012]
30. Obtain the Norton's equivalent at the terminals AB of the network shown in Fig.
[Oct./Nov.2011, Nov/Dec2003]
31. Verify the reciprocity theorem for the network shown in fig. [Oct./Nov.2007]
32. Find the voltage Vx in the circuit shown in figure below verify the reciprocity theorem. [Oct./Nov.2011]
33. In the single source network shown in Fig.the voltage 100 ∟45° V causes a current lx in the 5 ohm
branch. Find Ix and then verify the reciprocity theorem for this circuit. [Sep/Oct.2004]
34. In the network shown in Fig. find the voltage Vx. Interchange the position of the current source and the
voltage Vx and the reciprocity theorem. [Oct./Nov.2006]
35. In t he given network, find the value of ZL, which results in maximum power transfer. Calculate the
value o f maximum power. [March/April 2007]
36. In the circuit shown in Fig. the load Z L consists of a resistance RL. Find the value o f RL which the
source delivers ma x i mu m power to t he load. Determine t he value of maximum power.
[March/April 2008]
37. Find the value of RL which source delivers maximum power to it, and also find the maximum power
transferred to the load. [April/May 2010]
38. In the circuit shown in Fig, find the value of RL which results in maximum power transfer. Also calculate
the value of the maximum power delivered to load.
[April/May2011, Sep/Oct.2004, Oct./Nov.2009, March/April2013]
39. Using superposition theorem, find the polar form of the current through the 120Ω resistor shown in
figure. [April/May2011, 2012]
40. Find the thevenin’s equivalent of the circuit lying to the left of terminals A-B in the figure shown below:
[Oct/Nov2012]
41. Determine the maximum power delivered to the load in the circuit shown below: [Oct/Nov2012]
UNIT-4
SHORT ANSWER QUESTIONS: (3 MARKS)
1. Define coefficient of coupling and mutual inductance of a coupled circuit.
[March/April 2004, Oct./Nov.2006, 2007]
2. Define self-inductance and mutual inductance of a coupled circuit. [Oct/Nov2011, March/April 2003]
3. Explain dot convention used in coupled circuits.
[Oct./Nov.2006, 1997, 1998, 2007, 2009, 2010, 2011, 2012, March/April 2008, 2009, April/May 2011]
4. Define steady state and transient response. [March/April 2004, 2008, Oct./Nov.2008, April/May 2011]
5. Define time constant of a series RC circuit and mention its units.
[Oct./Nov.2006, 2007, 2008, 2011, March/April 2008, 2013]
6. Define time constant of a series RL circuit. [March/April 2003, 2008, Oct./Nov.2009, 2010]
7. Define time constant of series RC circuit. [Oct/Nov2012]
8. Explain how a high pass RC circuit works as an differentiator.
[March/April 2003, 2008Oct./Nov.2006, 2007, 2010]
9. Define the term linear wave shaping. [March/April 2008, 2009, April/May2012]
10. Explain the formation of double humps in a mutual inductive coupled tuned circuit.
[March/April 1997, Oct/Nov2012]
11. Two coils connected in series have an inductance of 3H when connected in aiding. If the self inductance
of first coil is 1H, what is the self inductance of the second coil?(Assume M=0.5)
[Oct./Nov.2007, April/May2011]
12. Derive relation between LSO, LSA and M. [Oct/Nov2010]
13. Give the expression for upper 3-dB frequency and rise time in terms of upper 3dB frequency a low pass
RC circuit. [March/April 2004, Oct./Nov.2007, 2008, 2012]
14. Explain reflected impedance of a coupled circuit briefly. [April/May2012]
15. Two coils connected in series have an equivalent inductance of 0.8H when connected in aiding, and an
equivalent inductance of 0.5H when connected in opposing. Calculate the mutual inductance of the
coils. [April/May2012]
16. Mention the applications of a differentiator and integrator circuits.
[Oct./Nov.2006, 2009, 2010, 2011 March/April 2008, 2009, April/May 2011]
17. Draw the high pass RC circuit and low pass RC circuit. [April/May2011]
18. When are double humps formed in the frequency response of a doubled tuned circuit?
[Oct/Nov2012, March/April2013]
19. For the circuit shown below, write the mathematical expression for the voltage VC(t) after the switch is
closed: [March/April2013]
ESSAY QUESTIONS: (5 TO 10 MARKS)
1. Derive relationship between L1, L2, M and K. [Oct/Nov2010]
2. Define coefficient of coupling of a coupled circuit and derive the relation k=
.
[March/April 2003, 2008, Oct./Nov.2008, 2010]
3. Derive the expression for the reflected impedance of inductively coupled circuit.
[March/April 2004, 1997]
4. Explain the effect of reflected impedance in a double tuned mutual inductive coupled circuit for
different degrees of coupling. [Oct./Nov.1997]
5. Derive the expression for equivalent inductance of Series aiding coupled circuit Series opposing coupled
circuit. [Oct./Nov.2007, 2009]
6. Derive the expression for transient voltage and current in a RL network. [April/May 2002]
7. Explain the response of high pass RC circuit for a pulse input. [April/May 1999, Oct./Nov.2009]
8. Show that RC low pass circuit works as an integrator.
[Oct./Nov.1998, 2009, 2011, April/May 1999, March/April 2008]
9. Derive transient voltage in R.C circuit for step input voltage. [April/May 1998]
10. Explain the transient analysis of series RLC circuit for over damping. [Oct./Nov.2006, 2007, 2010]
11. Derive the expression for lower 3-dB frequency of a high-pass RC circuit.
[Oct./Nov.2006, March/April 2008]
12. Explain the response of low pass RC circuit for a square wave input. [Oct./Nov.2008, March/April2013]
13. Explain the response of low pass RC circuit for step input voltage. [March/April 2009]
14. Explain the response of high pass RC circuit for a square wave input. [March/April 2009]
15. Explain the DC response of a series RLC circuit for under damped case. [Oct./Nov.2009, 2011]
16. If two identical coils have an equivalent inductance of 0.08H in series aiding and 0.035H in series
opposing, what are the values of L1, L2, M and K? [Oct./Nov.2008]
17. Two identical coils with L=0.02H have a coupling coefficient K=0.08. Find M and the two equivalent
inductances with the coils connected in series aiding and series opposing. [Oct/Nov2011]
18. Explain the terms steady state and transit state briefly. [April/May2012]
19. Two coils with inductances in the ratio of four to one have coupling coefficient k=0.6. When these coils
are connected in series aiding, the equivalent inductance is 44.4mH. find L1, L2 and M
20. Two inductively coupled coils have self inductances L1=40mH and L2=150mH. If the coefficient of
coupling is 0.7, find [Oct/Nov2012]
(i) The value of mutual inductance between the coils.
(ii) The maximum possible mutual inductance.
21. Find the voltage across the 5 ohm i n the circuit shown in figure below: [March/April 2008]
22. Obtain the dotted equivalent circuit for the coupled circuit shown in fig. Find the voltage across the –J10
ohms reactance using the equivalent circuit. [March/April 2002, 2004]
23. A series RL circuit with R = 50ohm, and L = 10H has a constant voltage V = 100 Volts applied a t t = 0
by closing a switch. Find the complete current. [Oct.2009, Nov.2003, April.2007, 2008, 2009]
24. A series RL circuit with R =30ohm, and L = 15H ha s a constant voltage V = 60V applied at t = 0 as
shown in Fig. De t e r mi ne t he current, t he voltage across the resistor and inductor at t = 0.2 sec.
[April.2002]
25. A series RC circuit consists o f R = 5000 ohm, C = 20 µ F has A constant voltage V = 100 V applied at
t = 0 and capacitor has no initial charge. Find the equations of i, VR andV0. [Sep./Oct.2004]
26. I n the RC circuit shown m figure the switch i s closed on position 1 at t=0 and after 1 TC is moved to 2.
Find the complete current transient. [March.2004]
27. For the circuit shown in figure, find the complete expression for current when the switch is closed a t
t = 0. [March/April 2009]
28. For the circuit shown below: [April/May2011, 2012]
(a) Find the time constant.
(b) After how many time constants will current have decayed to one half its maximum value?
29. The switch in figure is closed at t=0. [April/May2011]
(a) What is the time constant of the circuit ?
(b) Write the equation for VL(t)
30. The switch in the following figure is closed at t=o. [April/May2012, Oct/Nov2012]
(a) write the mathematical expressions for VL(t).
(b) i(t) and VR(t) after the switch is closed.
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