Previous Year Questions
1 paper · 44 questions — organised by subject with solutions and explanations.
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Given, is the gate-source voltage, is the drain source voltage, and is the threshold voltage of an enhancement type NMOS transistor, the conditions for transistor to be biased in saturation are
In the circuit below, the operational amplifier is ideal. If =10 mV and =50 mV, the output voltage ( ) is
The enhancement type MOSFET in the circuit below operates according to the square law. , the threshold voltage ( ) is 500 mV. Ignore channel length modulation. The output voltage is
A current controlled current source (CCCS) has an input impedance of 10 and output impedance of 100 k . When this CCCS is used in a negative feedback closedloop with a loop gain of 9, the closed loop
The asymptotic Bode magnitude plot of a minimum phase transfer function G(s) is shown below. Consider the following two statements. Statement I: Transfer function G(s) has three poles and one zero. St
The open loop transfer function of a unity feedback system is given by In G(s) plane, the Nyquist plot of G(s) passes through the negative real axis at the point
The characteristic equation of a linear time-invariant (LTI) system is given by The system is BIBO stable if
Consider a state-variable model of a system where y is the output, and r is the input. The damping ratio and the undamped natural frequency (rad/sec) of the system are given by
The transfer function of a phase lead compensator is given by The frequency (in rad/sec), at which is maximum, is
A 0.1 capacitor charged to 100 V is discharged through a 1 resistor. The time in ms (round off to two decimal places) required for the voltage across the capacitor to drop to 1V is ______
The line currents of a three-phase four wire system are square waves with amplitude of 100 A. These three currents are phase shifted by 120 with respect to each other. The rms value of neutral current
The current flowing in the circuit shown below in amperes is _____
The voltage across and the current through a load are expressed as follows The average power in watts (round off to one decimal place) consumed by the load is _______.
A moving coil instrument having a resistance of 10 , 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 f
A 220 V (line), three-phase, Y-connected, synchronous motor has a synchronous impedance of (0.25+j2.5) /phase. The motor draws the rated current of 10 A at 0.8 pf leading. The rms value of line-to-lin
A 220 V DC shunt motor takes 3 A at no-load. It draws 25 A when running at full-load at 1500 rpm. The armature and shunt resistances are 0.5 and 220 ,respectively. The no-load speed in rpm (round off
The magnetic circuit shown below has uniform cross-sectional area and air gap of 0.2 cm. The mean path length of the core is 40 cm. Assume that leakage and fringing fluxes are negligible. When the cor
A delta-connected, 3.7 kW, 400 V(line), three-phase, 4-pole, 50-Hz squirrel-cage induction motor has the following equivalent circuit parameters per phase referred to the stator: . Neglect shunt branc
A three-phase synchronous motor draws 200 A from the line at unity power factor at rated load. Considering the same line voltage and load, the line current at a power factor of 0.5 leading is
The parameter of an equivalent circuit of a three-phase induction motor affected by reducing the rms value of the supply voltage at the rated frequency is
A single-phase transformer of rating 25 kVA, supplies a 12 kW load at power factor of 0.6 lagging. The additional load at unity power factor in kW (round off to two decimal places) that may be added b
A 5 kVA, 50 V/100 V, single-phase transformer has a secondary terminal voltage of 95 V when loaded. The regulation of the transformer is
A six-pulse thyristor bridge rectifier is connected to a balanced three-phase, 50Hz AC source. Assuming that the DC output current of the rectifier is constant, the lowest harmonic component in the AC
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 voltageto be 75% of DC
A fully-controlled three-phase bridge converter is working from a 415V, 50 Hz AC supply. It is supplying constant current of 100 A at 400 V to a DC load. Assume large inductive smoothing and neglect o
A DC-DC buck converter operates in continuous conduction mode. It has 48 V input voltage, and it feeds a resistive load of 24 . The switching frequency of the converter is 250 Hz. If switch-on duratio
In a DC-DC boost converter, the duty ratio is controlled to regulate the output voltage at 48 V. The input DC voltage is 24 V. The output power is 120 W. The switching frequency is 50 kHz. Assume idea
A single-phase fully-controlled thyristor converter is used to obtain an average voltage of 180 V with 10 A constant current to feed a DC load. It is fed from single-phase AC supply of 230 V, 50 Hz. N
A three-phase 50 Hz, 400 kV transmission line is 300 km long. The line inductance is 1 mH/km per phase, and the capacitance is 0.01 per phase. The line is under open circuit condition at the receiving
In the circuit shown below, the switch is closed at t=0. The value of in degrees which will give the maximum value of DC offset of the current at the time of switching is
In a 132 kV system, the series inductance up to the point of circuit breaker locationis 50 mH. The shunt capacitanceat the circuit breaker terminal is 0.05 . The critical value of resistance in ohms r
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_________
The total impedance of the secondary winding, leads, and burden of a 5 A CT is 0.01 . If the fault current is 20 times the rated primary current of the CT, the VA output of the CT is ________
A 30 kV, 50 Hz, 50 MVA generator has the positive, negative, and zero sequence reactancesof 0.25 pu, 0.15 pu, and 0.05 pu, respectively. The neutral of the generator is grounded with a reactance so th
The matrix of a two-bus power system having two identical parallel lines connected between them in pu is given as The magnitude of the series reactance of each line in pu (round off up to one decimal
In the single machine infinite bus system shown below, the generator is delivering the real power of 0.8pu at 0.8 power factor lagging to the infinite bus. The power angle of the generator in degrees
The output response of a system is denoted as y(t), and its Laplace transform is given by The steady state value of y(t) is
A system transfer function is . If , and all other coefficients are positive, the transfer function represents a
The symbols, a and T, represent positive quantities, and u(t) is the unit step function. Which one of the following impulse responses is NOT the output of a causal linear time-invariant system?
A periodic function , with a period of , is represented as its Fourier series, . If the Fourier series coefficients of are
The inverse Laplace transform of is