Description : 32 With S2 closed and S1 open, the current waveform in the delta winding will be [GATE 2009] A. a sinusoidal at fundamental frequency B. flat-topped with third harmonic C. only third-harmonic D. none of these
Last Answer : C. Only third harmonic
Description : [31] With both S1 and S2 open, the core flux waveform will be [GATE 2009] A. a sinusoidal at fundamental frequency B. flat-topped with third harmonic C. peaky with third-harmonic D. none of these
Last Answer : B. Flat topped with third harmonic
Description : Describe the operation of inductor with sinusoidal AC voltage as input. Draw waveform for voltage across and current through the inductor. Draw its phasor representation.
Last Answer : An alternating voltage is applied to a purely inductive coil, a back e.m.f. is produced due to self-inductance of the coil. The back e.m.f. at every step, opposes the rise of fall of current through the coil ... drop, the applied voltage has to overcome this self induced e.m.f. only.
Description : Draw sinusoidal waveform of 3 phase emf and indicate the phase sequence.
Last Answer : Phase sequence is R-Y-B.
Description : Two sinusoidal signals having the same amplitude and frequency are applied to the X and Y inputs of a CRO. The observed Lissajous figure is straight line. The phase shift between the two signals would be (1) Zero (2) 90 degrees (3) Either zero or 180 degrees (4) Either 90 degrees or 270 degrees
Last Answer : Two sinusoidal signals having the same amplitude and frequency are applied to the X and Y inputs of a CRO. The observed Lissajous figure is straight line. The phase shift between the two signals would be (1) Zero (2) 90 degrees (3) Either zero or 180 degrees (4) Either 90 degrees or 270 degrees
Description : The anodes in a CRO are at ___________ potential with respect to the cathode a) negative b) high negative c) high positive d) positive
Last Answer : c) high positive
Description : The ___________ of a CRO controls the brightness of the spot formed on the screen a) Filament b) Grid c) Deflection plates d) Cathode
Last Answer : b) Grid
Description : A circuit which develops voltage across the horizontal deflection plates is known as a) Time base generator b) Electron gun c) Thermionic diode d) Zener diode
Last Answer : a) Time base generator
Description : Justify the need of current time base generator to obtain the specified sawtooth waveform with one example.
Last Answer : Justification:- * Current Time base generator is a circuit where the output current is a linear function of time over a specified time interval. * Time base circuits are used by radar systems to determine ... the time. * The diode D does not conduct during the sweep, because it is reverse biased.
Description : Anantenna thatis currentlypolarized usthe a. helical b. small circular loop c. parabolic reflector d. Yagi-Uda
Last Answer : a. helical
Description : Indicate the antenna thatisnotwideband: a. Discone b. Folded Dipole c. Helical d. Marconi
Last Answer : d. Marconi
Description : Whichofthe followingantennasis best excited fromawaveguide? a. Biconical b.Horn c. Helical d. Discone
Last Answer : b.Horn
Description : Helical antennas are oftenused forsatellite trackingatVHFbecauseof a. troposcatter b. superrefraction c. ionospheric refraction d.theFaradayeffect
Last Answer : d.theFaradayeffect
Description : If the input to a differentiating circuit is a saw-tooth wave, then output will be …………….. wave: A) square B) rectangular wave C) triangular wave D) rectified sine wave
Last Answer : If the input to a differentiating circuit is a saw-tooth wave, then output will be rectangular wave
Description : The induced emf is produced in a circuit due to: a. Initial magnetic flux b. final magnetic flux c. Change of magnetic flux d. constant magnetic flux
Last Answer : d. constant magnetic flux
Description : Explain how sinusoidal AC voltage is generated by using simple one loop generator.
Last Answer : An electric current produced by means of electrical machine is known as generator which converts mechanical energy into electrical energy. When conductor cuts the magnetic flux, emf induced in it. (Faraday' ... upon position of armature. The nature of emf is alternating as shown by the waveform.
Description : A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave?
Last Answer : A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave will be of 5 Hz.
Description : Which one of the following quantities is conserved in pair production? a) Energy b) Charge c) Linear momentum d) All
Last Answer : d) All
Description : What are the parts of a brushless AC generator?
Last Answer : Yoke, armature, stator, rotor, primary exciter, main exciter, rotary diode rectifier assembly, impeller, bearing & housing, end cover, terminal block, AVR.
Description : What is a shaft generator?
Last Answer : A shaft generator is coupled to the main engine. It uses the main engine as its prime mover and has a frequency converter (thyristor controlled) that converts the variable engine speed to near constant speed and ... speed (full speed) and not at manoeuvring speed. Ask E/O and 2/E for more details.
Description : How does the emergency generator start automatically?
Last Answer : It is activated by a under voltage relay. When there is blackout, the under voltage relay senses loss of voltage and starts up the emergency generator. Similarly when the power is restored, the relay stops the emergency generator. Ask E/) for more details.
Description : After a black out the emergency generator comes on; On restoring the main supply we are closing the circuit breaker of the main generator without bothering about synchronizing. How is this possible?
Last Answer : There is a power link connection breaker between the main generator and the emergency generator. During black out, this breaker trips. The emergency generator starts and its breaker closes and feeds only ... , there is no paralleling between main and emergency generator. Ask E/O for more details.
Description : If the AVR, is defective, when additional loads come on will the generator be able to take it?
Last Answer : No. Ask E/O and refer to Dennis T Hall.
Description : If you press the ACB Close button on an idle generator what will happen?
Last Answer : Ask E/O. Normally, the breaker won’t close until you synchronise, so even if you press the breaker close, it will not close. The breaker has under-voltage protection which will not let you close it.
Description : The only difference between construction of DC generator and Ac generator is that of: a. carbon brush b. Bar magnet c. electromagnet d. Horseshoe magnet
Last Answer : b. Bar magnet
Description : Which of the following converts electric energy into mechanical energy: a. Transformer b. DC generator c. Motor d. AC generator
Last Answer : d. AC generato
Description : Which component is mainly used in a DC generator: a.slip ring b. commutator c. magnet d. coil
Last Answer : b. commutator
Description : In the plane of AC generator coil is parallel to the field, then emf induced in coil is: a. maximum b. minimum c. zero d. intermediate
Last Answer : b. minimum
Description : Which one is not present in AC generator: a. Armature b. magnet c. slip ring d. commutator
Last Answer : c. slip ring
Description : The most common source of AC voltage is: a. motor b. generator c. cell d. transformer
Last Answer : c. cell
Description : The principle of AC generator is: a. Mutual induction b. self induction c. electromagnetic induction d. Induction
Last Answer : b. self induction
Description : In the plane of the A.C generator coil is perpendicular to the field, then induced emf in the coil is: a. Maximum b. minimum c. zero d. intermediate value
Description : Alternating current generator converts.......... energy into electrical energy? a. mechanical energy b. chemical energy c. solar energy d. potential energy
Last Answer : a. mechanical energy
Description : The Principle of an alternating current generator is based on: a. Coulomb’s law b. Ampere’s law c. Faraday’s law d. Lenz’s law
Last Answer : a. Coulomb’s law
Description : Briefly explain how an electrical generator converts mechanical energy into electrical energy.
Last Answer : Working principle of DC generator: * Working principle of DC generator is the principle of dynamically induced emf or electromagnetic induction. * According to this principle, when flux is cut by a conductor, an ... , the flux is cut by the armature winding and an emf is dynamically induced in it.
Description : Type of waveform generated by the sweep generator of the CRT
Last Answer : sawtooth
Description : I am 21 years old. I went to the doctor for TMJ problem and he saw the OPG and said I have not had a baby tooth yet. He did not go to the doctor anymore due to environmental problems. What can I do in this situation ?
Last Answer : You can pick up those milk teeth. Consult a dentist.
Description : This type threasher consist of spike tooth cylinder, woven wire mesh concave and upper casing provide with helical louvers. a. Hammer mill c. Dummy d. None of above
Last Answer : Ans- b. Axial flow
Description : This type of Cultivator suitable to work in hard and stony soils. a. Fixed tooth c. Helical tooth d. None of the above
Last Answer : Ans - b. Spring tooth
Description : It consists of spike tooth cylinder, woven- wire mesh concave and upper casing provided with helical concave. a) Dummy type c) Spike-tooth type b) Hummer type d) Axial flow type
Last Answer : Axial flow type
Description : The 'function generator' of the control circuit illustrated _______________. EL-0095 A. can be programmed to produce a non-linear output for a linear input depending on operating conditions B. is used for ... which or how many engines are needed for a required vessel speed D. all of the above
Last Answer : Answer: A
Description : As shown in the illustration, the circuit which 'shapes' the linear output of the thrust lever so that the steady-state ship speed is linear with respect to that lever's setting is the _____________. EL-0095 A. 'pitch controller' B. 'error amplifier' C. 'function generator' D. 'servo amplifier'
Last Answer : Answer: C
Description : The termresponsivityasit appliesto a light detectorisbest described as a. the time required for the signal to go from 10 to 90 percent of maximum amplitude b.the ratio ofthediode output currentto ... of output current to output power d. the ratio of output current to input current
Last Answer : b.the ratio ofthediode output currentto opticalinputpower
Description : Under ideal conditions, the collector current is (a) Equal to base current (b) Nearly equal to emitter current (c) Less than base current (d) always zero
Last Answer : (b) Nearly equal to emitter current
Description : In a transistor, the conventional current flows from base to emitter. The transistor is (a) NPN (b) PNP (c) FET (d) None of these
Last Answer : (a) NPN
Description : A part of transistor which is heavily doped to produce large number of majority carriers is (a) Emitter (b) Base (c) Collector (d) any of above
Last Answer : (a) Emitter
Description : Current gain of a transistor which has collector current of 10 mA and a base current of 40 micro Ampere is: (a) 25 (b) 250 (c) 2500 (d) 25000
Last Answer : b) 250
Description : In the transistor schematic symbol, the arrow ________ (a) located on emitter (b) located on base (c) located on collector (d) points from north to south
Last Answer : a) located on emitter
Description : For normal operation of a transistor, the collector base junction is kept (a) Unbiased (b) forward biased (c) reverse biased (d) none
Last Answer : (c) reverse biased
Description : The operation of a transistor requires ______ (a) Emitter is heated (b) base is heated (c) collector be heated (d) none of above
Last Answer : (d) none of above