Previous Year Questions
68 questions — organised by subject with solutions and explanations.
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A waveform generator circuit using OPAMPs is shown in the figure. It produces a triangular wave at point 'P' with a peak to peak voltage of 5 V for V. If the voltage is made +2.5 V, the voltage wavefo
A general filter circuit is shown in the figure : The output of the above circuit is given to the circuit shown below in figure : The gain v/s frequency characteristic of the output ( ) will be
A general filter circuit is shown in the figure : If and , the circuit acts as a
In the voltage doubler circuit shown in the figure, the switch 'S' is closed at t=0. Assuming diodes to be ideal, load resistance to be infinite and initial capacitor voltages to be zero. The steady s
The equivalent circuits of a diode, during forward biased and reverse biased conditions, are shown in the figure. If such a diode is used in clipper circuit of figure given above, the output voltage o
The truth table of monoshot shown in the figure is given in the table below : Two monoshots, one positive edge triggered and other negative edge triggered, are connected shown in the figure, The pulse
Two perfectly matched silicon transistor are connected as shown in the figure assuming the of the transistors to be very high and the forward voltage drop in diodes to be 0.7 V, the value of current I
The block diagrams of two of half wave rectifiers are shown in the figure. The transfer characteristics of the rectifiers are also shown within the block. It is desired to make full wave rectifier usi
The transfer function of a system is given as . This system is
Figure shows a feedback system where The range of K for which the system is stable will be given by
The transfer functions of two compensators are given below : Which one of the following statements is correct ?
The asymptotic Bode magnitude plot of a minimum phase transfer function is shown in the figure : This transfer function has
The transfer function of a linear time invariant system is given as The steady state value of the output of the system for a unit impulse input applied at time instant t=1 will be
A function y(t) satisfies the following differential equation : where (t) is the delta function. Assuming zero initial condition, and denoting the unit step function by u(t), y(t) can be of the form
The state space equation of a system is described by , where is state vector, u is input, y is output and , , A unity feedback is provided to the above system G(s) to make it a closed loop system as s
An input device is interfaced with Intel 8085A microprocessor as memory mapped I/O. The address of the device is 2500H. In order to input data from the device to accumulator, the sequence of instructi
A 3-line to 8-line decoder, with active low outputs, is used to implement a 3-variable Boolean function as shown in the figure The simplified form of Boolean function F(A,B,C) implemented in 'Product
The content of some of the memory location in an 8085 accumulator based system are given below The content of stack (SP), program counter (PC) and (H,L) are 2700H, 2100H and 0000H respectively. When t
The current i(t) sketched in the figure flows through a initially uncharged 0.3 nF capacitor. The capacitor charged upto 5 s, as per the current profile given in the figure, is connected across an ind
The Thevenin's equivalent of a circuit operation at =5 rads/s, has V and . At this frequency, the minimal realization of the Thevenin's impedance will have a
The resonant frequency for the given circuit will be
The number of chords in the graph of the given circuit will be
The time constant for the given circuit will be
Two 8-bit ADCs, one of single slope integrating type and other of successive approximate type, take times to convert 5 V analog input signal to equivalent digital output. If the input analog signal is
The ac bridge shown in the figure is used to measure the impedance Z . If the bridge is balanced for oscillator frequency f = 2 kHz, then the impedance Z will be
Two sinusoidal signals and are applied to X and Y inputs of a dual channel CRO. The Lissajous figure displayed on the screen shown below : The signal will be represented as
Distributed winding and short chording employed in AC machines will result in
It is desired to measure parameters of 230 V/115 V, 2 kVA, single-phase transformer. The following wattmeters are available in a laboratory: W1 : 250 V, 10 A, Low Power Factor W2 : 250 V, 5 A, Low Pow
A 3-phase, 440 V, 50 Hz, 4-pole slip ring induction motor is feed from the rotor side through an auto-transformer and the stator is connected to a variable resistance as shown in the figure. The motor
A 400 V, 50 Hz 30 hp, three-phase induction motor is drawing 50 A current at 0.8 power factor lagging. The stator and rotor copper losses are 1.5 kW and 900 W respectively. The friction and windage lo
A 400 V, 50 Hz, 4-pole, 1400 rpm, star connected squirrel cage induction motor has the following parameters referred to the stator: Neglect stator resistance and core and rotational losses of the moto
Three single-phase transformer are connected to form a 3-phase transformer bank. The transformers are connected in the following manner : The transformer connecting will be represented by
In a stepper motor, the detent torque means
A 230 V, 50 Hz, 4-pole, single-phase induction motor is rotating in the clockwise (forward) direction at a speed of 1425 rpm. If the rotor resistance at standstill is 7.8 , then the effective rotor re
A 220 V 20 A, 1000 rpm, separately excited dc motor has an armature resistance of 2.5 . The motor is controlled by a step down chopper with a frequency of 1 kHz. The input dc voltage to the chopper is
The core of a two-winding transformer is subjected to a magnetic flux variation as indicated in the figure. The induced emf ( ) in the secondary winding as a function of time will be of the form
A 220 V, 1400 rpm, 40 A separately excited dc motor has an armature resistance of 0.4 . The motor is fed from a single phase circulating current dual converter with an input ac line voltage of 220 V (
A synchronous motor is connected to an infinite bus at 1.0 pu voltage and draws 0.6 pu current at unity power factor. Its synchronous reactance is 1.0 pu resistance is negligible. Keeping the excitati
A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 and the field winding resistance is 80 . The external resistance to be added in
A capacitor consists of two metal plates each 500x500 and spaced 6 mm apart. The space between the metal plates is filled with a glass plate of 4 mm thickness and a layer of paper of 2 mm thickness. T
A coil of 300 turns is wound on a non-magnetic core having a mean circumference of 300 mm and a cross-sectional area of 300 . The inductance of the coil corresponding to a magnetizing current of 3 A w
Two point charges C and C are placed at coordinates (1,1,0) and (-1,-1,0) respectively. The total electric flux passing through a plane z = 20 will be
A single-phase half controlled converter shown in the figure feeding power to highly inductive load. The converter is operating at a firing angle of 60 . If the firing pulses are suddenly removed, the
A single phase fully controlled converter bridge is used for electrical braking of a separately excited dc motor. The dc motor load is represented by an equivalent circuit as shown in the figure. Assu
A 3-phase voltage source inverter is operated in 180 conduction mode. Which one of the following statements is true ?
In the circuit shown in the figure, the switch is operated at a duty cycle of 0.5. A large capacitor is connected across the load. The inductor current is assumed to be continuous. The average voltage
A single phase source inverter is feeding a purely inductive load as shown in the figure The inverter is operated at 50 Hz in 180 square wave mode. Assume that the load current does not have any dc co
In the single phase voltage controller circuit shown in the figure, for what range of triggering angle ( ), the input voltage ( ) is not controllable ?
A single phase fully controlled bridge converter supplies a load drawing constant and ripple free load current, if the triggering angle is 30 , the input power factor will be
A three phase fully controlled bridge converter is feeding a load drawing a constant and ripple free load current of 10 A at a firing angle of 30 . The approximate Total harmonic Distortion (%THD) and
Single line diagram of a 4-bus single source distribution system is shown below. Branches have equal impedances. The load current values indicated in the figure are in per unit. Distribution company's
An extra high voltage transmission line of length 300 km can be approximate by a lossless line having propagation constant = 0.00127 radians per km. Then the percentage ratio of line length to wavelen
A loss less power system has to serve a load of 250 MW. There are tow generation (G1 and G2) in the system with cost curves respectively defined as follows: where are the MW injections from generator
Voltages phasors at the two terminals of a transmission line of length 70 km have a magnitude of 1.0 per unit but are 180 degree out of phase. Assuming that the maximum load current in the line is of
A two machine power system is shown below. The Transmission line XY has positive sequence impedance of and zero sequence impedance of An 'a' phase to ground fault with zero fault impedance occurs at t
A-3-phase transmission line is shown in figure : Voltage drop across the transmission line is given by the following equation : Shunt capacitance of the line can be neglect. If the has positive sequen
Consider a power system shown below: Given that: p.u; The positive sequence impedance are p.u and p.u 3-phase Base MVA = 100 voltage base = 400 kV(Line to Line) Nominal system frequency= 50 Hz. The re
A loss less single machine infinite bus power system is shown below : The synchronous generator transfers 1.0 per unit of power to the infinite bus. The critical clearing time of circuit breaker is 0.
A loss less transmission line having Surge Impedance Loading (SIL) of 2280 MW is provided with a uniformly distributed series capacitive compensation of 30%. Then, SIL of the compensated transmission
A signal is the input to a real Linear Time Invariant system. Given K and are constants, the output of the system will be of the form where
The impulse response of a causal linear time-invariant system is given as h(t). Now consider the following two statements : Statement (I): Principle of superposition holds Statement (II): h(t)=0 for W
H(z) is a transfer function of a real system. When a signal is the input to such a system, the output is zero. Further, the Region of convergence (ROC) of H(z) is the entire Z-plane (except z = 0). It
Let ) (where for and zero otherwise. Then if , the Fourier Transform of will be given by
A system with x(t) and output y(t) is defined by the input-output relation : The system will be
Given a sequence x[n], to generate the sequence y[n]=x[3-4n], which one of the following procedures would be correct ?
Let x(t) be a periodic signal with time period T, Let for some . The Fourier Series coefficients of y(t) are denoted by . If for all odd k , then can be equal to
Given with , the residue of at z=a for will be
A signal where is a real constant is the input to a Linear Time Invariant system whose impulse response , where is a real constant. If min denotes the minimum of and similarly, max denotes the maximum