VINAYAKA MISSIONS UNIVERSITY V.M.K.V.ENGINEERING COLLEGE DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING I YEAR B.E.(EEE) - PT ELECTRIC CIRCUIT ANALYSIS (Common to EEE,ECE) UNIT-I PART A 1. State kirchoff’s laws. 2. Compare series and parallel circuits. 3. Define: branch, node, loop 4. A 5Ω and 15Ω resistors are connected in series to the 50 v battery and 20 Ω and 15 Ω resistors are connected in parallel to the same battery. Determine the total resistance value? 5. Two resistors are connected in parallel and a voltage of 200volts is applied to the terminals. The total current taken is 25A. find equalent resistance of the circuit R 1 R 2 v = 2 0 0 v o lt s 6. Calculate the equivalent resistance of the following combination of resistor and source current. 12 ohm s 16 ohm s 4 ohm s 6 ohm s 40 ohm s 2 0 v o lt s 7. Compare AC and DC circuit 8. What are the types of sources? 9. Give the conditions of voltage and current division 10. Define RMS value and form factor Part-B 1. Write the mesh equations for the circuit shown in the figure and determine the current In 12Ω resistor. 1k 2 ohm s 4 ohm s 4 ohm s 600 V 7 ohm s 480 V 2. Apply mesh current method and determine currents through the resistors of the Network shown in figure. 2 ohm s - j2 o h m s 3 ohm s - j1 5 o h m s j1 5 o h m s 1 0 < 0 v o lt s 1 ohm s 3) Calculate the effective resistance between points A&B in the given circuit A 2 O hm 3 ohm 4 ohm 2 ohm 6 ohm 6 ohm 2 ohm 2 ohm 5 ohm 5 ohm 3 ohm B 4) A wheat stone bridge circuit is made up of the following resistors AB=3Ω BC=6Ω and CD=15 Ω and DA=7 Ω . A 30 V battery is connected between A&C. Find the current Through a 10Ω galvanometer connected between B&D using loop method. 5)Determine the voltages (i) Vdf and (ii)Vag from given circuit 6. (i) Find the Equivalent resistance and the current in each resistance. 3 ohm 18 ohm 2 ohm 50v 2 ohm 8 ohm (ii) Apply KCL & KVL to the circuit in the following fig. find the current in each branch 15 ohm 30 ohm 100 V 50 V 20 ohm UNIT-II PART-A 1. Define transient response. 2. Define forced response. 3. Compare steady state and transient state 4. Define transient state and transient time 5. Draw the dc response of R-L circuit and the response curve. 6. Draw the dc response of R-C circuit and the response curve 7. Draw the dc response of R-L –C circuit and the response curve 8. Draw the sinusoidal response of R-L circuit and write the differential equation. 9. Draw the sinusoidal response of R-C circuit and write the differential equation. 10. Draw the sinusoidal response of R-L -C circuit and write the differential equation. PART-B 1. In the network shown in below switch K is kept open for very long time. On closing switch, after 10 milliseconds, capacitor voltage attains a value of 80V. then the switch is kept closed for very long time. When switch is again opened, capacitor voltage becomes 90V after half second. Calculate the value of R & C for given circuit 2. In the circuit shown in fig. the switch is closed at t=0. Determine and sketch iL(t) and VL(t) for t>0. Assume at t=0, the current in the inductance is zero. 3. In the network shown in fig. switch k is initially kept open and network reaches steady state. At t=0, switch k is closed. Find an expression for current through inductor for t>0.Sketch current waveform. 4. In the network shown in fig. switch k is closed and a steady state is reached in the network. At t=0, the switch is opened. Find an expression for the current in the inductor, i2(t). TCLOSE = k=0 1 2 10 ohm 100 V 1mH 20 micro F 5. In the Fig. shown a network in which steady state is reached with switch k open. At t=0, switch k is closed. For the element values given, determine the values of Va(0-) and Va(0-). UNIT-III PART-A 1. Write the condition of resonance. 2. Define band width 3. Draw the series resonance circuit and the phasor diagram. 4. Draw the parallel resonance circuit and the phasor diagram. 5. Compare series and parallel resonance circuit. 6. Define Resonance 7. For the circuit shown in fig determine the value of capacitive reactance and Impedance at resonance. 50 ohm +J 25 -J x c Vs 8. Define of Q- factor. 9. Give the classification of resonance PART –B 1. (i) Derive the resonant frequency of series circuit. (ii) Short notes on Q- factor and its effect on band width. 2. (i) Derive the band width of RLC circuit. (ii) A coil having a resistance of 50 Ω and an inductor of 0.2 H is connected in series with a variable capacitor across a 60 v, 50 Hz supply .calculate the capacitance required to produce resonance and the corresponding values of (a)current (b)voltage across the coil and the capacitor (c)the power factor (d)Q-factor. 3. A inductive coil of resistance 10 Ω and inductive 0.1 Henrys is connected in parallel with a 150 μF capacitor to a variable frequency, 200V supply. Find the resonant frequency at which the total current taken from the supply is in phase with the supply voltage. Also find the value of this current. Draw the phasor diagram. 4. A choke coil and pure resistance are connected in series across 230V, 50 Hz, A.c. supply. If the voltage drop across coil is 190V and across resistance is 80V while current drawn by the circuit is 5A. Calculate, i) internal resistance of coil ii) inductance of coil iii) resistance R, iv) power factor of the circuit v) power consumed by the circuit. 5. (i) A series RLC circuit consists of 50 Ω resistance, 0.2 A inductance and 10 µ₣ capacitor with the applied voltage of 20 v .determine the resonant frequency, Q-factor of the circuit and compute the lower and upper frequency limits and also find the band width of the circuit. UNIT -IV PART-A 1. State Super position Theorem 2. State Thevenin’s Theorem 3. State Norton’s Theorem 4. State Maximum power transfer theorem 5. State Millman’s Theorem 6. State Reciprocity Theorem 7. State Compensation theorem 8. State Tellegen’s theorem 9. Write the expression for Maximum power transfer in terms of Thevenin’s voltage and load resistance 10. How to change the (a) current source into voltage source (b) voltage source into current source? PART-B 1. (a) Find the Voltage Across the 2Ω resistor by using super position theorem 2 ohm 3 ohm 20 ohm 10 v 2 A 20 v 5 ohm 10 ohm 2. (a) For the circuit shown below find the Theveniens equivalent circuit, across the terminals A and B .calculate the current through a 2 Ω resistor connected across the terminals AB 2 ohm 2 ohm 25 v 10 ohm A B 4 ohm 5 A 5 ohm 1k 3. Find the voltage between points A&B in fig below using Norton’s theorem 4. For the circuit of the fig find the value RL for maximum power delivered to it. Also Calculate also the maximum load power. 1 .2 o h m 10 ohm V5 R L 1 2 .5 V 0 .6 o h m 0 .4 o h m 1 .4 o h m 1 .4 o h m 5. Use Millmans theorems to find the voltage across the terminals A and B and also the current through RL = 5 Ω A 3 ohm 4 ohm 6 ohm R L=5 O hm 6v 20 v B 6. (i) State substitution theorem (ii) In the network shown in fig (a) the 5 Ω resistor is changed to 8 Ω determine the change in the current through (3+j4) Ω impedance. 5 ohm 3 ohm j 5 ohm 10 v j4 o h m 7. For the circuit shown in figure. Determine the load current by applying Thevenin’s theorem. j4 o h m j5 o h m (12) 1 0 0 a n g le 0 d e g r e e IL j3 o h m j5 o h m UNIT-V PART-A 1. What is the difference between balanced and unbalanced circuit? 2. Define power 3. Define power factor 4. Two inductively coupled coils have self inductance L1=45 mH and L2=150 mH. If the co-efficient of coupling is 0.5 (i) find the value of mutual inductance between the coils and (ii) what is the maximum possible mutual inductance? 5. What is floating neutral? 6. Write the types of unbalanced load? 7. What is the symmetrical component method and give the components? 8. What is a positive sequence component? 9. What is a negative sequence component? 10. What are a zero sequence components? PART-B 1. Explain three phase power measurement by 2 wattmeter method for star and delta connected load and determine the power equation and draw the phasor diagram. 2. . (i) Derive the expression for balanced star connected load and draw the phasor diagram. (ii) Give the short notes on symmetrical component and un-symmetrical component. 3 . 4 A delta connected three phase load with the impedances (28+j0) Ω, (25+j45) Ω is onnected across a three phase 230V, 50 Hz, symmetrical RYB supply. Find the line and phase currents in magnitude and phase. Draw the necessary circuit diagram. 5 A balanced star-connected load is supplied from a symmetrical, 3 phase 440V, 50Hz supply system. The current in each phase is 20A and lags behind its phase voltage by an angle of 2П/9 radians. Calculate line voltage, phase voltage, current in each phase, load parameters, power in each phase, total power, readings of the two wattmeters, connected in the load circuit to measure the total power. Draw a neat vector/phasor diagram. Prove that a 3φbalanced load draws 3 times as much power when connected in delta, as it would draw when connected in star