# C-14 ELECTRICAL CIRCUITS Subject code : EE-303

SYLLABUS FOR UNIT TESTS

ELECTRICAL CIRCUITS

Subject code : EE-303

Syllabus for unit test –I

 Sl. No. Major Topics Periods Weightage Short Questions Essay Questions 1. D.C Circuits 12 26 02 02 2 Network Theorems 6 10 - 01 3 Fundamental of A.C. 8 19 03 01

Syllabus for unit test -II
 4 Single phase A.C. circuits 14 26 02 02 5 Parallel circuits 8 13 01 01 6 Poly phase circuits 12 16 02 01 Total 60 110 10 08

UNIT TEST-I
MODEL PAPER-I
PART-A

NOTE :   Answer all questions.                                                                   2*3=6
Each question carries two marks

1. State Kirchhoff’s laws
2. Define (a) RMS Value (b) Average Value
3. The current flowing in a circuit is expressed as i=200sin314t.calculate its frequency, form       factor and peak factor.
PART-B
NOTE:  Answer any two questions                                                                 2*7=14
Each question carries seven marks

4. Derive the formula for delta to star transformation.
5. State and explain super position theorem.
6. (A) Explain about phase and phase difference                                                                         (3)
(b)Write the formula for RMS value and average value of full wave rectified sine wave (2)
(c) Convert the A=100 /͟͟45° from polar to rectangular form                                                    (2)

UNIT TEST-I
MODEL PAPER-II
PART-A
Each question carries two marks

1. State the limitations of ohm’s law.
2. State the relation between poles, speed and frequency.
3. Define (a) frequency (b) form factor (c) junction
PART-B
NOTE: Answer any two questions                                             2*7=14
Each question carries seven marks

4. Two batteries E1 and E2 have emf’s12 volts and 8 volts respectively and external resonance of 2 ohms and 1 ohm respectively are connected in parallel across 10 ohms resistor. Calculate (a) the current in each of the battery and external resistor (b) the potential difference across external resistor.
5. State and explain maximum power transfer theorem.
6. (a) convert the rectangular (8+j6) into polar form
(b) An alternating current of frequency 60HZ has maximum value of 120 amp. Write down the equation for instantaneous value. Reckoning time from the instant the current is zero and the becoming positive. Find (a) the instantaneous value after 1/360 seconds (b) the time taken to reach 96 amps for the first time

UNIT TEST-II
MODEL PAPER-I
PART-A
NOTE :  Answer all questions                                                                 2*3=6
Each question carries two marks

1. Define resonance in series circuit
2. Define (a) conductance (b) susceptance (c) admittance
3. State the relations between line and phase values of delta connected method and also write the expression for power in 3-phase delta connected system.
PART-B
NOTE: Answer any two questions                                          2*7=14
Each question carries seven marks

4. A resistance of 12 ohms, an inductance of 0.15 H and a capacitance of 100 micro farad are connected in series across a 100V, 50HZ, AC supply.
Calculate, (a) Impedance (b) current (c) power factor (d) power consumed.
5. A coil of 50 ohms resistance and an inductance of 0.3H is connected in parallel with a 50 micro farad capacitor. Calculate the frequency at which the circuit will act as non inductive resistances of “R”ohms also find the value of R.
6. Derive the relation between the phase and line voltages, phase and line current for a balanced 3phase load in star connected system.

UNIT TEST-II
MODEL PAPER-II
PART-A
Each question carries two marks

1. Define Q-Factor of R-L-C series circuit.
2. State the conditions for resonance in parallel AC circuits.
3. List the advantages of poly phase system over single phase system.
PART-B
NOTE: Answer any two questions                                                      2*7=14
Each question carries seven marks

4. A coil of resonance 40 ohms and inductance of 0.75 H form a part of RLC series circuits for which the resonance frequency is 60 HZ. Find the capacitance and also find (a) line current (b) power factor (c) voltage across the coil the supply voltage is 250V, 50HZ.
5. Two circuits of impedances Z1= (10+j15) ohms and Z2= (6-j8) ohms are connected in parallel across a 230 volts, 50Hz AC supply. Calculate the total current and power factor by each branch.
6. Derive an expression for power in 3 phase circuits by two watt meter method.

BOARD DIPLOMA EXAMINATIONS, (C-14)
DEEE-THIRD SEMISTER EXAMINATIONS
MODEL PAPER-I
ELECTRICAL CIRCUITS
SUB CODE:EE-303
Time: 3Hours                                                                      Total marks: 80

PART-A                                                           10X3=30
2) Each answer carries three marks.
3) Answer should be brief and straight to the point and shall not exceed
five simple sentences.
1. Define (a) Active circuit (b) Passive circuit (c) linear circuit?
2. State Kirchhoff’s laws?
3. Define (a) Frequency (b) Form factor (c) Peak factor?
4. Convert the rectangular form (10+j15) into polar form?
5. Write an expression for RMS value and average value of full wave rectified sine wave?
6. Define Q-Factor series resonant circuit?
7. The current flowing through a pure capacitor is 23amps.Find the capacitance, when the voltage applied across the capacitor v=200sin314t.
8. Define Resonance and write the equation for resonant frequency for parallel circuit?
9. State the relation between the line voltage and phase voltage, line current and phase current in star connected network?
10. (a) Define the term “Poly phase ”
(b) What is meant by phase sequence?
PART-B                                                          5*10=50
Instructions:           1) Answer any five questions.
2) Each answer carries ten marks.

11.A wheat stone bridge ABCD is arranged as follows. AB=10 ohm, BC=10 ohm, CD=4 ohm, DA=50 ohm. A galvanometer of 20 ohm resistance is connected across BD. Calculate the current through the galvanometer when p.d of 10 volts is maintained across A&C.
12.   Derive the formulas for star to delta transformation.
13.  State and explain Maximum power transfer theorem and mention its applications.
14. (a) Define RMS value and Average value?
(b) A sinusoidal wave is represented by i=42.42sin628t. Determine its (a) RMS value (b) form factor (c) peak factor.
15. A coil of resistance 100 ohms and inductance of 0.318 H is connected in series with a capacitor across a 230 V, 50 Hz, AC Supply. If the current drawn is 1.15/͟60° amps. Calculate the capacitance of the capacitor, voltage across inductance and power consumed in the circuit.
16. A coil of resistance 2 ohms and inductance of 0.01 H is connected in series with a capacitor across 200 V supply. What must be the capacitor in order that maximum current occurs at a frequency of 50 Hz. Also find (a) maximum current (b) voltage across the coil (c) voltage across the capacitor.
17. A circuit of (10+j15) ohms is connected in parallel with another circuit of (6-j8) ohms this is connected across 220 volts, 50 Hz, AC supply. Find (a) total current (b) total power drawn by the circuit. Also draw the vector diagram.
18. A 3 phase 400 volts motor has a power factor of 0.4 lagging. Two watt meters are connected in the circuit to measure the input. They show that the input to be 30 kw.find the reading of each instrument.

BOARD DIPLOMA EXAMINATIONS, (C-14)
DEEE-THIRD SEMISTER EXAMINATIONS
MODEL PAPER-II
ELECTRICAL CIRCUITS
SUB CODE: EE-303
Time: 3Hours                                                              Total marks: 80

PART-A                                                           10X3=30
2) Each answer carries three marks.
3) Answer should be brief and straight to the point and shall not
Exceed five      simple sentences.
1. Define junction, branch and loop in circuits.
2. State the limitations of ohm’s law.
3. Define (a) cycle (b) time period (c) frequency.
4. Convert the polar form 100 /͟30° into rectangular form.
5. Define RMS value and average value.
6. A pure inductance coil taken a current of 15 amps for 200volts, 50 Hz, AC Supply find the inductance of the coil.
7. Define resonance and write the formula for the resonant frequency for RLC series circuit.
8. Why a parallel resonant circuit is called a rejecter circuit.
9. List the advantages of poly phase system over single phase system.
10. State the relation between line voltage and phase voltage, line current and phase current in delta connected network.

PART-B                                                           5*10=50
Instructions:           1) Answer any five questions.
2) Each answer carries ten marks.

11. Two batteries E1 and E2 have emf’s 6 volts and 2volts respectively and external resistances of  2 ohms and 3 ohm respectively are connected in parallel across 5 ohms resistor. Calculate   (a) the current in each of the battery (b) the potential difference across 5ohms resistor.
12. Derive the formula for delta to star transformation.
13. State and explain about thevenens theorem.
14. (a) Explain about phase and phase difference.
(b) A sine wave has a peak valve of 50 volts Determine (a) RMS value (b) Average value (c)     form factor.
15. A resistance of 12 ohms, an inductance of 0.15 H and a capacitance of 100 micro farad are connected in series across a 100V, 50HZ, AC supply.
Calculate, (a) Impedance (b) current (c) power factor (d) power consumed.
16. Draw and explain the graphical representation of series resonance and indicate the following in the graph.
(a) Resonant frequency (b) net reactance (c) impedance (d) current.
17. (a) Define Q factor of a parallel resonant circuit.
(b) A coil of 20 ohms resistance and an inductance of 0.2H is connected in parallel with a   condenser of 100 micro farad capacitance. Calculate the frequency at which the circuit will act as a non inductance resistance of “R”ohms.also find the value of “R”.
18. (a) Derive the formula for measurement of 3 phase power and power factor by using two watt meter method (balanced load).