Q. The voltage 𝑣(𝑡) across the terminals a and b as shown in the figure, is a sinusoidal voltage having a frequency 𝜔 = 100 radian/s. When the inductor current 𝑖(𝑡) is in phase with the voltage 𝑣(𝑡), the magnitude of the impedance Z (in Ω) seen between the terminals a and b is (up […]

Q. A dc to dc converter shown in the figure is charging a battery bank, B2 whose voltage is constant at 150 V. B1 is another battery bank whose voltage is constant at 50 V. The value of the inductor, L is 5 mH and the ideal switch, S is operated with a switching frequency

Q. A 200 V DC series motor, when operating from rated voltage while driving a certain load, draws 10 A current and runs at 1000 r.p.m. The total series resistance is 1 Ω. The magnetic circuit is assumed to be linear. At the same supply voltage, the load torque is increased by 44%. The speed

Q. The figure shows two buck converters connected in parallel. The common input dc voltage for the converters has a value of 100 V. The converters have inductors of identical value. The load resistance is 1 W. The capacitor voltage has negligible ripple. Both converters operate in the continuous conduction mode. The switching frequency is

Q. The voltage across the circuit in the figure, and the current through it, are given by the following expressions: 𝑣(𝑡) = 5 − 10 cos(𝜔𝑡 + 60°) V 𝑖(𝑡) = 5 + 𝑋 cos(𝜔𝑡) A where 𝜔 = 100 𝜋 radian/s. If the average power delivered to the circuit is zero, then the value

Q. The capacitance of an air-filled parallel-plate capacitor is 60 pF. When a dielectric slab whose thickness is half the distance between the plates, is placed on one of the plates covering it entirely, the capacitance becomes 86 pF. Neglecting the fringing effects, the relative permittivity of the dielectric is __________(up to 2 decimal places). Ans:

Q. In the circuit shown in the figure, the bipolar junction transistor (BJT) has a current gain 𝛽 = 100. The base-emitter voltage drop is a constant, 𝑉𝐵𝐸 = 0.7 𝑉. The value of the Thevenin equivalent resistance 𝑅𝑇ℎ (in Ω) as shown in the figure is ___________(up to 2 decimal places). Ans: 89 – 91.5

Q. The signal energy of the continuous-time signal x(t) = [(t -1) u(t -1)]-[(t – 2)u(t – 2)]-[(t – 3)u(t – 3)]+[(t – 4)u(t – 4)] is (A) 11/3                      (B) 7/3                        (C) 1/3                       (D) 5/3 Ans: 5/3

Q.Digital input signals 𝐴, 𝐵, 𝐶 with 𝐴 as the MSB and 𝐶 as the LSB are used to realize the Boolean function 𝐹 = 𝑚0 + 𝑚2 + 𝑚3 + 𝑚5 + 𝑚7, where 𝑚𝑖 denotes the 𝑖𝑡ℎ minterm. In addition, 𝐹 has a don’t care for 𝑚1. The simplified expression for 𝐹 is

Q. Which one of the following statements is true about the digital circuit shown in the figure A. It can be used for dividing the input frequency by 3. B. It can be used for dividing the input frequency by 5. C. It can be used for dividing the input frequency by 7. D. It