GATE EE: 2018 Mini Mock 10 for ESE & GATE EE Exams

Question 1

The critical value of gain for the system is 80. The system is operating at a gain of 40. The G.M. (dB) of the system is______?

Question 2

find the incremental resistance in the circuit given below considering each diode n=3, V_η = 0.8 V, dc forward resistance of diode is R_f = 0 Ω. Assuming initially when s is open V₀ = 2.4 V?

Question 3

Consider the circuit given below

Initially D flip flop was cleared. S₀, S₁ are select inputs and I is input data.
Which of the following statement is incorrect?

Question 4

If an ideal transformer has an inductive load element at port 2 as shown in the figure below, the equivalent inductance at port 1 is

Question 5

An alternator is connected to an infinite bus delivering current of 1.2 pu at 0.85 p.f. lagging. Infinite bus voltage is (V) = 1 pu and power angle of alternator is δ = 60 °. The reactance of the alternator is 1.4 pu and excitation voltage is 1.8 pu. The active power output of the alternator is –

Question 6

A synchronous generator of 100 MVA, 50 Hz is delivering power to infinite bus. The excitation voltage of generator is 1.8 pu and bus voltage is 1.1 pu. Reactance of generator is 1 pu. What will be the power angle of the generator if synchronizing power coefficient is 0.99 pu.

Question 7

A half wave rectifier diode circuit have following parameters:
R = 10Ω, L=2m H, C = 10 µF. V_S=230V
The circuit is initially relaxed, With switch closed at t=0, determine conduction time of diode ------------ (fill in the blanks)

Question 8

A 3 – phase full converter bridge is connected to supply voltage of 230V per phase and a frequency of 50Hz. The source inductance is 2 m H. the load current on dc side is constant 20 A, If the load consists of internal emf 400 V with internal resistance 1Ω, then firing delay angle in degrees is ______ (fill in the blanks upto 2 decimal places)

Question 9

A signal is modulated using the sinusoidal Pulse Width Modulation. The pulse width of the modulated signal corresponding to zero amplitude is selected as 2 µs. The width varies with the amplitude of the signal such that: at +1 V, width = 4 µs, and at -1 V, width = 0 µs. Determine the pulse width, when the amplitude is – 0.6 V

Question 10

Figure shows an ideal three–winding transformer. The three windings 1, 2, 3 of the transformer are wound on the same core as shown. The turn’s ratio N₁:N₂:N₃ is 4:2:1. A resistor of 10W is connected across winding–2. A capacitor of reactance 2.5W is connected across winding–3. Winding–1 is connected across a 400 V, ac supply. If the supply voltage phasor V₁ = 400∠0 °, the supply current phasor I₁ is given by