GATE

Q. The enhancement type MOSFET in the circuit below operates according to the square law. 𝜇𝑛𝐶𝑜𝑥 = 100 μA/V2, the threshold voltage (VT) is 500 mV. Ignore channel length modulation. The output voltage Vout is   (A) 100 mV   (B) 500 mV   (C) 600 mV   (D) 2 V Ans: 600 mV

Q. A moving coil instrument having a resistance of 10 Ω, gives a full-scale deflection when the current is 10 mA. What should be the value of the series resistance, so that it can be used as a voltmeter for measuring potential difference up to 100 V? (A) 9 Ω (B) 99 Ω (C) 990

Q. The asymptotic Bode magnitude plot of a minimum phase transfer function 𝐺(𝑠) is shown below. (A) Statement I is true and statement II is false. (B) Statement I is false and statement II is true. (C) Both the statements are true. (D) Both the statements are false. Ans: Statement I is false and statement

Q. The output voltage of a single-phase full bridge voltage source inverter is controlled by unipolar PWM with one pulse per half cycle. For the fundamental rms component of output voltage to be 75% of DC voltage, the required pulse width in degrees (round off up to one decimal place) is  Solution: The output voltage

Q. The total impedance of the secondary winding, leads, and burden of a 5 A CT is 0.01 Ω. If the fault current is 20 times the rated primary current of the CT, the VA output of the CT is Solution: Given that, impedance of secondary winding = 0.01 Ω Rated current = 5 A

Q. Five alternators each rated 5 MVA, 13.2 kV with 25% of reactance on its own base are connected in parallel to a busbar. The short-circuit level in MVA at the busbar is                  . Ans: 100 Solution: Reactance of each alternator = 0.25 As all the five alternators are connected in parallel, the equivalent reactance

Q. If 𝑓 = 2𝑥3 + 3𝑦2 + 4𝑧, the value of line integral ∫𝐶 grad𝑓 ∙ 𝑑𝐫 evaluated over contour C formed by the segments (-3, -3, 2)→(2, -3, 2) →(2, 6, 2) →(2, 6, -1) is Ans:

Q. A current controlled current source (CCCS) has an input impedance of 10 Ω and output impedance of 100 kΩ. When this CCCS is used in a negative feedback closed loop with a loop gain of 9, the closed loop output impedance is (A) 10 Ω (B) 100 Ω (C) 100 kΩ (D) 1000 kΩ

Q. Given, 𝑉𝑔𝑠 is the gate-source voltage, 𝑉𝑑𝑠 is the drain source voltage, and 𝑉𝑡ℎ is the threshold voltage of an enhancement type NMOS transistor, the conditions for transistor to be biased in saturation are (A) 𝑉𝑔𝑠 < 𝑉𝑡ℎ ; 𝑉𝑑𝑠 ≥ 𝑉𝑔𝑠 − 𝑉𝑡ℎ (B) 𝑉𝑔𝑠 > 𝑉𝑡ℎ ; 𝑉𝑑𝑠 ≥ 𝑉𝑔𝑠 − 𝑉𝑡ℎ

Q. The characteristic equation of a linear time-invariant (LTI) system is given by ∆(𝑠) = 𝑠4 + 3𝑠3 + 3𝑠2 + 𝑠 + 𝑘 = 0. The system is BIBO stable if Ans: Option (C) Solution: