The torque speed characteristic of a repulsion motor resembles which of the following dc motor characteristic?

A periodic rectangular signal, x(t) has the wave form shown in figure. Frequency of the fifth harmonic of its spectrum is

The Boolean expression for the output of the logic circuit shown in figure is

Which type of motor is most suitable for computer printer drive?

Which material is used in controlling chain reaction in a nuclear reactor?

The depletion region or space charge region or transition in a semiconductor p-n junction diode has

In the circuit shown in figure X is an element which always absorbs power. During a particular operations, it sets up a current of 1 amp in the direction shown and absorbs a power . It is possible that X can absorb the same power   for another current i, the value of this current is

The performance of a general two-port network N shown in the figure can be described in terms of its z-parameters of h-parameters as indicated below

If the two-port is further characterized by additional constraints, a few conditions have to be satisfied by the parameters of the network. For each of the constraints specified in Table A, choose the appropriate condition to be satisfied, from amongst those listed in Table B.

The voltage series feedback in a feedback amplifier leads to

In the series RC circuit shown in figure the voltage across C starts increasing when the d.c. source is switched on. The rate of increase of voltage across C at the instant just after the switch is closed
(i.e., at ), will be

The V-I characteristic as seen from the terminal- pair (A, B) of the network of figure is shown in figure. If an inductance of value 6mH is connected across the terminal-pair (A, B), the time constant of the system will be

In an oscilloscope, the input to the horizontal plates is a 100 Hz voltage signal. The Lissajous patterns (A), (B) and (C) will be generated when different frequency voltage signals are applied to vertical plates. Match each Lissajous pattern to the corresponding frequency .

If the reference bus is changed in two load flow runs with same system data and power obtained for reference bus taken as specified P and Q in the latter run

During a disturbance on a synchronous machine, the rotor swings from A to B before finally settling down to a steady state at point C on the power angle curve. The speed of the machine during oscillation is synchronous at point(s)

In the transistor amplifier shown in figure, the ratio of small signal voltage gain, when the emitter resistor , is bypassed by the capacitor  to when it is not bypassed, (assuming simplified approximate h-parameter model for transistor), is

In a thyristor dc chopper, which type of commutation results in best performance?

For an unbalanced fault, with paths for zero sequence currents, at the point of fault

The closed-loop transfer function of a control system is given by . For the input , the steady state value of c(t) is equal to

Insider a hollow conducting sphere

In a 8085 microprocessor, the following instructions may result in change of accumulator contents and change in status flags. Choose the correct match for each instruction.

The energy stored in the magnetic field of solenoid 30 cm long and 3 cm diameter wound with 1000 turns of wire carrying a current of 10A is

If v, w, q stand for voltage, energy and charge, then v can be expressed as

In a 3-phase controlled bridge rectifier, with an increase of overlap angle, the output dc voltage

A water boiler at home is switched on the a.c. mains supplying power at 230V/50Hz. The frequency of instantaneous power consumed by the boiler is

Which semiconductor power device out of the following is not a current triggered device?

A coil (which can be modeled as a series RL circuit) has been designed for high-Q performance at a rated voltage and a specified frequency. If the frequency of operation is doubled, and the coil is operated at the same rated voltage, then the Q-factor and the active power P consumed by the coil will be affected as follows

The triac can be used only in

The unit-impulse response of a unit-feedback control system is given by

The open loop transfer function is equal to

Resistance switching is normally employed in

Which of the following does not cause permanent damage of an SCR?

If the fault current is 2000A, the relay setting is 50% and CT ratio is 400:5, the plug setting multiplier will be

A 4 pole generator with 16 coil has a two layer lap winding. The pole pitch is

Consider the unit-step response of a unity-feedback control system whose open-loop transfer functions is . The maximum overshoot is equal to

A 4 pole dynamo with wave wound armature has 51 slots containing 20 conductors in each slot. The induced EMF is 357 volts and the speed is 8500 rpm. The flux per pole will be

A non-inverting Op-Amp amplifier is shown in figure. The output voltage  is         

For a feedback control system of type 2, the steady state error for a ramp input is

An advantage of a permanent magnet moving coil instrument is that it is

A cylindrical rotor synchronous motor is switched on the supply with its field winding shorted on themselves. It will

Out of the following factors for a dc machine,         

(i) Inter pole                

(ii) Armature resistance

(iii) Armature leakage reactance        

(iv) Armature reaction

(v) Reduction in field current

The factors that are responsible for decrease in the terminal voltage of a shunt generator are

The moving coil in a dynamometer wattmeter is connected

For the system shown in figure, with a damping ratio  of 0.7 and an undamped natural frequency

 of 4 rad/sec, the values of K and a are         

In figure the characteristic that corresponds to the variation of synchronous reactance of a synchronous motor with field current is

Unbalanced supply voltage given to a 3-phase, delta-connected induction motor will cause

The function of oil in a transformer is

Let the magnitude of the gain in the inverting OP-Amp amplifier circuit shown in be x with switch S1 open. When the switch S1 is closed the magnitude of gain becomes

Auto-transformer is used in transmission and distribution

When the supply voltage to an induction motor is reduced by 10%, the maximum torque will decrease by approximately

The unit impulse response of a system is given as . The step response of the same system for  is equal to

During hunting of synchronous motor

For a given frequency, the deflecting torque of an induction ammeter is directly proportional to

Keeping in view the requirement of parallel operation, which of the 3-phase connections given below are possible?

The scale of a voltmeter is uniform. Its type is

An induction motor having full load torque of 60Nm when delta-connected develops a starting torque of 120Nm. For the same supply voltage, if the motor is changed to star-connection, the starting torque developed will be

In case of a split phase motor, the phase shift between currents in the two windings is around

In an induction motor, if the air gap is increased

Out of the several characteristics shown in figure identify the appropriate ones to match the following for a 3-phase induction motor.

 x-axis                        y-axis

(a) Load         efficiency                (P) curve-I

(b) Speed        current                 (Q) curve-II

(c) Speed         power factor        (R) curve-III

                        (S) curve-IV

                                (T) curve-V

For a 500Hz frequency excitation, a 50km long power line will be modeled as

For equilateral spacing of conductors of an untransposed 3-phase line, we have

The per unit voltages of two synchronous machines connected through a lossless line are. Match the two sides in the following