EEE - ECT - ELECTRICAL CIRCUIT THEORY STUDY MATERIALS

 

EEE - ECT - ELECTRICAL CIRCUIT THEORY STUDY MATERIALS

*ECT IMPORTANT*

Problems on

U1 : Kirchoff law, Mesh, Node

U2 : Super position theorem, Nortons Theorem

U3 : RL, RC, RLC 

U4 : Admittance method or Compare Series & Parallel, Parallel Resonance

U5 : Wattmeter Method

Unit 1 important

1. State and explain Kirchoffs law ? 

2. Derive the expression for 3 resistors connected in series or parallel

3. Kirchoffs law problem

4. Mesh method problem

5. Nodel method problem

Unit 2 important 👇

1. State and explain Super Position Theorem

2. Super position Theorem problem

3. Norton Theorem problem

UNIT 3

*IMPORTANT PROBLEMS*

1. Derive the expression for Impedance in RL or RL or RLC Series Circuit

2. A coil of resistance 10Ω and an inductance of 0.1 H is connected in series with a capacitance of 150μF with a voltage of 200V, 50Hz supply. Calculate (i) inductive reactance (ii) capacitive 

reactance (iii) impedance (iv) current (v) power factor (vi) voltage across the coil and 

capacitor.

3. A resistor of 100Ω is connected in series with 50μF capacitor to supply of 200V, 50Hz. Find (i) impedance (ii) current (iii) power factor (iv) voltage across the resistor and (v) voltage 

across capacitor.

4. Find the impedance, current and phase angle of the series circuit having a resistance of 10Ω

and inductance of 10millihenry. The applied voltage is 200V, 50Hz.

5. Derive the expression for Average Value or RMS Value?

*UNIT 4*

*IMPORTANT PROBLEMS*

1. Compare Series & Parallel Response? 

2. An inductive circuit of resistance 2 Ohms and inductance of 0.01H is connected to a 250V, 50Hz supply. What capacitance placed in parallel will produce resonance? Find the total current taken from the supply and the current in each branch circuits.

3. A coil of resistance 12Ω and inductance 0.12 H is connected in parallel with a 60µF capacitor to a 100 Volt variable frequency supply. Calculate (i) the frequency at which the circuit will act as a non-inductive resistor (ii) the value of dynamic impedance at resonance.

4. In a RLC series resonance circuit a resistance of 10 Ω and an inductance of 20mH is connected in series with a 0.5 MFD capacitor. Calculate i) Resonance frequency ii) Q-factor of the coil iii) Bandwidth and iv) Power consumed at resonance if applied voltage to circuit is 200V a.c.

5. Two impedances Z1 = 8+j6 and Z2 = 3-j4 are connected in parallel across 230V, 50Hz supply. Calculate (a) Current in each branch (b) the total current of the circuit (c) power factor (d) Power taken by the circuit.

UNIT5 

*IMPORTANT problemS*

1. The power input to a 2000V, 50Hz, three phase motor is measured by two wattmeters which indicate 330KW and 120KW respectively. Calculate the input power, power factor and line current.

2. A three phase 440 volts motor operates with a power factor of 0.65. Two wattmeters are connected to measure the input power, and the total power taken from the mains is 33KW. 

Find the readings of each wattmeter.

3. A 3 phase motor delivers an output of 46KW and operated within efficiency of 90% at 0.85 lagging power factor. Calculate the line current and total power drawn if the supply voltage is 400V.

4. A balanced star connected load of (8+j6) ohms per phase is connected to a 3 phase 230V 

supply. Find the line current, power factor, power and total volt ampere.

5. Three similar coils each having a resistance of 15Ω and inductance of 0.5 H are connected in delta to a three phase 415V, 50Hz supply. Find the i) Line Current ii) P.F and iii) Power