UPSC Electrical Engineering 2025

(a) In the circuit given below, find the voltages at point A and point B. 10 marks (b) Determine the time domain signal x(t) corresponding to the DTFT given below : 10 marks (c) D…

(a) In the circuit shown in the diagram, initially key K₁ is closed and capacitor has no charge (at time t = 0). Now at time t = 10 seconds, key K₁ is opened and at t = 18·68 seco…

(a) Consider the Boolean function: F(A, B, C, D) = Σ m (1, 3, 4, 11, 12, 13, 14, 15). Implement it with a 4-to-1 multiplexer and external gates. Connect inputs A and B to the sele…

(a) For the Schottky transistor circuit shown below, determine I_B, I_D, I_C and V_CE. Next, remove the Schottky diode and determine I_B, I_D, I_C and V_CE assuming additional val…

(a) As shown in the figure, just inside the surface of a dielectric slab, the electric field (E₁) is 15 V/m and it makes an angle of 30° with the surface. The electric field (E₂)…

(a) (i) What is meant by armature reaction in DC machines ? Show with the help of developed view of armature conductors and poles that the effect of armature m.m.f. on the main fi…

(a) It is given that E⃗ = Eₘ sin (ω t - α z) â_y in free space α > 0. (i) Determine D⃗, B⃗ and H⃗. Plot E⃗ and H⃗ at t = 0. State clearly if any assumption is made. (ii) Show tha…

(a) (i) Show that the Smith chart constructed for a lossless transmission line gives a family of r-circles, having a radius of 1/((1+r)) for each circle which is centred at Γᵣ = r…

(a) The block diagram of a system is as shown below : Evaluate the overall transfer function (Y(s))/(R(s)) using block diagram reduction technique. 10 (b) Explain the operation pe…

(a) An LTI system with the following state-space representation is given : ẋ = [0 1] x + [0] u [0 -0.5] [k] y = [1 0] x Design a phase lead compensator so that the system achieves…

(a) (i) Sketch the approximate root locus plot for a time-delay system approximated by the transfer function G(s) = (K(1-s/2))/(s(s+1)(1+s/2)) Also compute the largest value of K…

(a) (i) Consider a second-order type-1 system with no zeros. The system under unity feedback admits a resonant peak of 1·36 at resonant frequency 8·2 rad/s. Compute the transfer f…

(a) Given a second-order linear time-invariant system G(s) with a relative degree of 2. G(s) admits a zero steady-state error for unit step input and steady-state error of 0·1 for…

(a) Determine the sending-end voltage, current, power factor of a single-phase, 50 Hz, 76·2 kV transmission line delivering a load of 12 MW at 0·8 p.f. lagging. The line constants…

(a) Two generators are connected in parallel to the low-voltage side of a 3-phase, Δ-Y transformer as shown below : Generator 1 is rated 60 MVA, 13·8 kV Generator 2 is rated 30 MV…

(a) The figure below shows the single-line diagram of a generator connected through parallel transmission lines to an infinite bus. The machine is delivering 1 pu power, and both…