First Year (FE)
- How do you add or subtract sinusoidal AC quantities using phasors and complex numbers? In one line To add or subtract sinusoids of the same frequency, write each as a phasor in rectangular form (a + jb) , add or subtract the re... 1
- How do current and voltage behave in purely resistive, inductive and capacitive AC circuits? In one line In a pure resistor current is in phase with voltage, in a pure inductor current lags voltage by 90°, and in a pure capacitor cur... 1
- How do you analyse a series RL circuit: impedance, phase angle and power factor? In one line In a series RL circuit the impedance is Z = √(R² + X_L²) , the current lags the voltage by φ = tan⁻¹(X_L/R) , and the power fact... 1
- How do you analyse a series RC circuit and why does its current lead the voltage? In one line In a series RC circuit the impedance is Z = √(R² + X_C²) and the current leads the supply voltage by φ = tan⁻¹(X_C/R) , giving a... 1
- How do you analyse a series RLC circuit and decide if it is inductive or capacitive? In one line In a series RLC circuit Z = √(R² + (X_L - X_C)²) ; if X_L > X_C it behaves inductively (current lags), if X_C > X_L capacitively... 1
- What is admittance, and how is it used to solve parallel AC circuits? In one line Admittance Y = 1/Z measures how easily a branch allows AC to flow; in a parallel circuit, branch admittances simply add, making... 1
- What are real power, reactive power, apparent power and power factor in an AC circuit? In one line Real power P = VIcosφ (W) does useful work, reactive power Q = VIsinφ (VAR) flows back and forth to build magnetic and electric... 1
- What is series resonance in an RLC circuit and what is its resonant frequency? In one line Series resonance occurs at the frequency where X_L = X_C , so the impedance becomes purely resistive and minimum, the current is... 1
- How are three-phase voltages generated and why are they displaced by 120 degrees? In one line Three identical coils placed 120° apart on the same rotor (or stator) of an alternator produce three equal sinusoidal EMFs that... 1
- What is parallel resonance, and how does it differ from series resonance? In one line Parallel resonance occurs in a coil-capacitor parallel (tank) circuit when the reactive currents of the two branches cancel, mak... 1
- What are line and phase voltage and current relations in a balanced star connection? In one line In a balanced star (Y) connection, line voltage is √(3) times phase voltage and leads it by 30°, while line current equals phase... 1
- What are line and phase voltage and current relations in a balanced delta connection? In one line In a balanced delta (Δ) connection, line voltage equals phase voltage, while line current is sqrt3 times phase current and lags... 1
- How does source transformation convert a voltage source into an equivalent current source? In one line A practical voltage source V with series resistance R can be replaced by a current source I = V/R with the same R in parallel, a... 1
- What are Kirchhoff's current law and voltage law, and how do you apply them to a circuit? In one line Kirchhoff's Current Law (KCL) says the total current entering a node equals the total current leaving it, and Kirchhoff's Voltag... 1
- How do star-delta and delta-star transformations simplify resistor networks? In one line Star-delta transformation replaces three resistors connected in a star (Y) with an equivalent set of three in a delta (triangle)... 1
- What is the difference between ideal and practical voltage and current sources? In one line An ideal source gives a fixed voltage (or current) no matter what load is connected, while a practical source has internal resis... 1
- What does the superposition theorem state and how is it used with multiple sources? In one line In a linear circuit with several independent sources, the current or voltage in any element equals the algebraic sum of the valu... 1
- How do you solve a DC circuit using mesh analysis with mesh currents? In one line Mesh analysis assigns a loop current to each window (mesh) of a planar circuit, writes KVL for every mesh, and solves the result... 1
- How does Thevenin's theorem replace a complex network by a single source and resistance? In one line Thevenin's theorem says any linear two-terminal network can be replaced by one voltage source V_th in series with one resistance... 1
- How do you solve a DC circuit using nodal analysis with node voltages? In one line Nodal analysis picks one node as reference (0 V), writes KCL at every other node in terms of unknown node voltages, and solves f... 1
- How does Norton's theorem represent a network as a current source with parallel resistance? In one line Norton's theorem says any linear two-terminal network can be replaced by a current source I_N in parallel with a resistance R_N... 1
- What is the maximum power transfer theorem and what load resistance gives maximum power? In one line A source delivers maximum power to a load when the load resistance equals the Thevenin resistance of the source network, R_L = R... 1
- What is the working principle of a single-phase transformer and why does it not work on DC? In one line A transformer works on mutual induction: an alternating current in the primary winding sets up an alternating flux in the iron c... 1
- What are core-type and shell-type transformers and how do their constructions differ? In one line Core-type and shell-type transformers differ in how the windings and iron core are arranged: in core type the windings surround... 1