EIL Placement Papers - Electrical, Electronics & Instrumentation Questions

EIL Placement Papers - Electrical, Electronics & Instrumentation Questions

Q. For a 30 volt, 90 watt lamp to work properly in a 120 volt supply, the required series resister in ohm is
a) 10
b) 20
c) 30
d) 40

Q. According to Thevenin’s theorem, any linear active network can be replaced by a single voltage source
(A) in series with an impedance
(B) in parallel with an impedance
(C) in series with two impedances
(D) in parallel with two impedances

Q. The internal resistance of an ammeter is
a) Very small
b) Infinite
c) Very high
d) zero

Q. Hay bridge is used for the measurement of
a) Resistance
b) inductance
c) Capacitance
d) conductance

Q. Which of the following is true about series resonance
a) The reactance turns into zero and impedance becomes equal to resistance
b) The current in the circuit turns into maximum
c) The voltage drop across inductance and capacitance cancel each other
d) All of the above

Q. A 3-?, 4 wire, 400/230 v feeder supplies 3-phase motor and an unbalanced lighting load. In the circuit,
a) All four wires will carry the same current
b) neutral wire will have no current
c) neutral wire will hold both motor current and lighting load current
d) neutral wire will bear current only when lighting load is turned on

Q. Equalizing connections are required when there is a parallel connection of two
a) alternators
b) compound generators
c) series generators
d) both b and c

Q. An ideal transformer is one that
a) Has interleaved primary and secondary windings
b) has no losses and magnetic leakage
c) has core of stainless steel and windings of pure copper metal
d) has a common core for its primary and secondary windings

Q. The principle of operation of a 3-phase induction motor is analogous to that of a
a) Synchronous motor
b) capacitor-start, induction-run motor
c) transformer with a shorted secondary
d) repulsion-start induction motor

Q. In the forward region of a diode’s characteristics, it appears as
a) an OFF switch
b) an ON switch
c) a capacitor
d) a high resistance

Q. The common-emitter forward amplification factor ßdc is given by
a) IC/IE
b) IC/IB
c) IE/IC
d) IB/IF

Q. An important characteristic of a common emitter amplifier
a) Low voltage gain
b) Signal phase reversal
c) very high output impedance
d) moderate power gain

Q. after VDS reaches pinch-off value VP in a JFET, drain current IO grows to be
a) Zero
b) Low
c) saturated
d) Reversed

Q. An electronic oscillator
a) Needs an external input
b) supplies its own input
c) is an amplifier
d) is a dc/ac converter

Q. In a SCR, the function of the gate is to
a) Turn it off
b) manage its firing
c) make it unidirectional
d) reduce the forward breakdown voltage

Q. NAND and NOR gates are called ‘universal’ gates since they
a) Are available all over
b) are widely used in IC packages
c) can be combined to produce OR, AND and NOT gates
d) are very easy to be manufactured

Q. Registers and counters are similar as they both
a) Calculate pulses
b) store binary information
c) Are made from an array of flip-flops and integrated on a single chip
d) are shift registers

Q. A flip-flop
a) is a sequential logic device
b) is a combinational logic device
c) retains information previously stored in it
d) both a and c

Q. An operational amplifier
a) can be used to sum two or more signals
b) can be used to subtract two or more signals
c) all of the above

Q. TTL logic is preferred over DTL logic because
a) it has greater fan-out
b) greater logic levels are possible
c) it has greater fan-in
d) It has less power consumption

Q. An electron reaching a potential of 250 V will acquire an energy of :
a) 250 eV
b) 800 eV
c) 250 Joules
d) 800 Joules

Q. If either donor type or acceptor type impurity, added to the intrinsic semiconductor, is controlled to 1 part in one million, the conductivity of the sample
a) is increased by a factor 103
b) is reduced by a factor 10-3
c) is increased by a factor 106
d) is reduced by a factor 10-6

Q. Laplace transform and Fourier integrals are related by
a) frequency domain
b) time domain
c) both frequency and time domain
d) none of the above

Q. A clamper circuit can
(i) add or subtract a dc voltage to or from a waveform
(ii) not change the shape of the waveform
(iii) amplify the waveform

a) (i) and (ii) are correct
b) (i) and (iii) are correct
c) (ii) and (iii) are correct
d) (i), (ii) and (iii) are correct

Q. A ring counter consisting of five flip flops will have
a) 5 states
b) 10 states
c) 32 states
d) Infinite number of states

Q. Which of the following may be used as a parallel to series converter?
a) Decoder
b) Encoder
c) A Digital Counter
d) A Multiplexer

Q. An interrupt in which an external device supplies its address as well as the interrupt request, is known as
a) A vectored interrupt
b) Non Maskable Interrupt
c) Polled Interrupt
d) Maskable Interrupt

Q. An instruction that may be used without conversion must be written in :
a) Source code
b) Machine Language
c) Basic language
d) Assembly Language

Q. The angle at which no reflection takes place and the incident wave is vertically polarized is called
a) Steradian angle
b) Critical angle
c) Brewster’s angle
d) Reflection angle

Q. A Phase Locked Loop is used for demodulation of
a) Pulse Amplitude Modulation signals
b) Pulse Code Moduation signals
c) PM signals
d) DSB-SC signals

Q. The important function of balanced modulator is
a) To generate balanced modulation of a carrier wave
b) To generate 100 percent modulation
c) To suppress carrier signal in order to create a single side band or double side band signal
d) Limit noise selected at the receiver

Q. An SCR can also be called a
(A) DC switch
(B) AC switch
(C) Both DC and AC switch
(D) Square wave generator

Q. Fiber optics communication offers a bandwidth in the range
a) 1010 Hertz
b) 106 Hertz
c) 1014 Hertz
d) 1020 Hertz

Q. In which region the Silicon photo sensors have their maximum spectral response?
a) infra red region
b) ultra violet region
c) visible region
d) X-ray region

Q. What is the other name of PID controller?

Q. A 4 Bit word is called_____.

Q. Which is the highest priority interrupt.

Q. A shunt is made of______?
a) Copper
b) Tungsten
c) Maganin

Q. In a 4kva, 400/200 v m/c the value of impedance & reactance are given as 0.002 & 0.006. What will be the new values of the impedence and reactance when referred to the h.v side?
a) 0.2, 0.6
b) 0.08, 0.036
c) 0.4, 0.12

Q. Purpose of Metallic sheath is to
a) prevent the cable from moisture
b) provide mechanical strength

Q. Of the following bridges, bridge that may be used for the measurement of dielectric loss of a capacitor is
a) Anderson bridge
b) Heaviside Campbell equal ratio voltage
c) Schering bridge
d) Owen bridge

Q. Diac has
a) 3-layers and 2-junctions
b) 2-.layers and 3-junctions
c) 4-layers and 3-junctions

Q. Which is not linked to circuit breaker?
a) conservator
b) explosion pot
c) operating mechanism

Q. Coefficient of reflection of a short transmission line is
a) 1
b) -1
c) 0
d) infinite

Q. A d.c chopper converts
a) ac to ac
b) dc to dc
d) dc to ac

Q. In a controlled rectifier, the nature of the load current is continous or discontinous
a) does not depend on the type of load & firing angle delay
b) depends on load & the firing angle delay
c) depends only on the type of load
d) depends only on the firing angle delay

Q. For thyrister, pulse triggering is preferred over dc triggering because
a) its gate dissipation is low
b) the pulse system is simpler
c) triggering system is required for very short duration
d) all of the above

Q. Thyristers are
a) SCRs
b) TRIACs
c) both SCRs and TRIACs
d) all the pnpn devices