question: The Barkhausen criterion for an oscillator

options:
- Loop gain should be unity
- Loop gain should be less than unity
- The phase of a feedback signal with respect to input should be 0° or 360°
- Both A and C


question: Potentiometer method of DC voltage measurement is more accurate than direct measurement using a voltmeter because

options:
- It loads the circuit moderately.
- It loads the circuit to maximum extent.
- It uses centre zero galvanometer instead of voltmeter.
- It does not load the circuit at all.


question: Which of these sets of logic gates are designated as universal gates?

options:
- NOR, NAND.
- XOR, NOR, NAND.
- OR, NOT, AND.
- NOR, NAND, XNOR.


question: A single phase one pulse controlled circuit has a resistance R and counter emf E load 400 sin(314 t) as the source voltage. For a load counter emf of 200 V, the range of firing angle control is

options:
- 30° to 150°.
- 30° to 180°.
- 60° to 120°.
- 60° to 180°.


question: A box which tells the effect of inputs on control sub system is known as

options:
- Data Box.
- Logical box.
- Decision box.
- State box.


question: Two infinite parallel metal plates are charged with equal surface charge density of the same polarity. The electric field in the gap between the plates is

options:
- same as that produced by one plate.
- double the field produced by one plate.
- dependent on coordinates of field points.
- zero.


question: The resistance in the circuit of the moving coil of a dynamometer wattmeter should be

options:
- Low.
- Very low.
- High.
- Almost zero.


question: The following are the necessary requirements of an oscillator

options:
- Amplitude stability
- Frequency stability
- Power stability
- Both A and B


question: The normal voltage used in directional heating is

options:
- 1.5 KV.
- 15 KV.
- 33 KV.
- 66 KV.


question: LC oscillators are used for produce a waveform with frequency ranging from

options:
- 1MHz to 500 MHz
- 100 KHz to 500 MHz
- 1 KHz to 1 MHz
- 1MHz to 100 GHz


question: A working diode must have

options:
- High resistance when forward or reverse biased
- Low resistance when forward biased, while high resistance when reverse bias
- High resistance when forward biased, while low resistance when reverse bias
- Low resistance when forward or reverse biased


question: What is the name of the fluorescent material that gives red colour fluorescence?

options:
- Zinc silicate.
- Calcium silicate.
- Zinc sulphide.
- Magnesium silicate.


question: How many bits are required to store one BCD digit ?

options:
- 1
- 2
- 3
- 4


question: Commutator in DC generator is used for

options:
- collecting of current
- reduce losses
- increase efficiency
- convert AC armature current in to DC


question: 1 F is theoretically equal to

options:
- 1 ohm of resistance
- ratio of 1 V to 1 C
- ratio of 1 C to 1 V
- none of these


question: How many entries will be in the truth table of a 3 input NAND gate ?

options:
- 3
- 6
- 8
- 9


question: In decimal number system what is MSD

options:
- First digit from left to right
- First digit from right to left
- Middle digit
- Mean of all digits


question: In Digital Logic Designs, GAL is abbreviated as

options:
- General Advance Logic
- General Array Logic
- Generic Advance Logic
- Generic Array Logic


question: Inintel 8085A microprocessor ALE signal is made high to

options:
- Enable the data bus to be used as low order address bus
- To latch data D0-D7 from data bus
- To disable data bus
- To achieve all the functions listed above


question: For an SCR gate cathode characteristic is a straight line of 130. For triggered source volume of 15 V and allowable gate power dissipation of 0.5 W compute the gate source resistance?

options:
- 111.9 ohm
- 11.19 ohm
- 108 ohm
- 115 ohm


question: The concept of V/f control of inverters driving induction motors resuls in

options:
- constant torque operation
- speed reversal
- reduced magnetic loss
- hormonic elimination


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

options:
- 0.015 joule.
- 0.15 joule.
- 0.015 joule.
- 1.15 joule.


question: While operating on variable frequency supplies, the AC motor requires variable voltage in order to

options:
- protect the insulation.
- avoid effect of saturation.
- improve the capabilities of the inverter.
- protect thyristor from dV / dt.


question: Which of the following windings are necessary in case of all dc machines?

options:
- closed winding
- lap winding
- wave winding
- open type winding


question: Relaxation Voltage controlled oscillators are used to generate

options:
- Sinusoidal wave
- Triangular wave
- Sawtooth wave
- Both B and C


question: The supply frequency usually employed for high frequency eddy current heating is

options:
- 1 KHz.
- 5 KHz.
- 10 MHz.
- 10 KHz to 400 KHz.


question: In the toggle mode a JK flip-flop has

options:
- J = 0, K = 0.
- J = 1, K = 1.
- J = 0, K = 1.
- J = 1, K = 0.


question: Electric drive is becoming more and more popular because

options:
- all of below.
- it provide smooth and easy control.
- it is cheaper in cost.
- it is simple and reliable.


question: A step up chopper has input voltage 110 V and output voltage 150 V. The value of duty cycle is

options:
- 0.32.
- 0.67.
- 0.45.
- 0.27.


question: A Binary number system has how many digits.

options:
- 0
- 1
- 2
- 10


question: Lowest critical frequency is due to pole and it may be present at the origin or nearer to the origin, then the type of network is

options:
- LC.
- RL.
- RC.
- Any of the above.


question: Advantages of open loop control system is/are

options:
- simple and economical.
- accurate.
- reliable.
- all of the above.


question: The voltage induced in an inductor is represented as,

options:
- product of its inductance and current through it.
- ratio of its inductance to current through it.
- ratio of current through it to its inductance.
- product of its inductance and rate of change of current through it.


question: If a Hexadecimal number needs to convert to binary. For each hexadecimal digit, there will be how many bits

options:
- 1
- 2
- 4
- 8


question: Induction heating takes place in

options:
- conducting but non-magnetic materials.
- conducting materials which may be either magnetic or non-magentic materials.
- insulating materials.
- conducting and magnetic materials.


question: In a lap winding dc machine number of conductors are 100 and number of parallel paths are 10. Find the average pitch

options:
- 10
- 100
- 50
- 1


question: Magnetic flux has the unit of

options:
- Newton
- Ampere turn
- Weber
- Tesla


question: In balanced bridge, if the positions of detector and source are interchanged, the bridge will still remain balanced. This can be explained from which theorem

options:
- Reciprocity theorem
- Thevinin's theorem
- Norton's theorem
- Compensation theorem


question: A D-flip-flop is said to be transparent when

options:
- the output is LOW
- the output is HIGH
- the output follows clock
- the output follow input


question: A Lissajous pattern on an oscilloscope has 5 horinzontal tangencies and 2 vertical tangencies. The frequency of horizontal input is 100 Hz. The frequency of the vertical will be

options:
- 500 Hz.
- 250 Hz.
- 400 Hz.
- 625 Hz.


question: Speed control by variation of field flux results in

options:
- constant power drive.
- constant torque drive.
- variable power drive.
- none of the above.


question: Which of the following memories uses one transistor and one capacitor as basic memory unit

options:
- SRAM
- DRAM
- Both SRAM and DRAM


question: What will be the number of lamps, each having 300 lumens, required to obtain an average illuminance of 50 lux on a 4m * 3m rectangular room?

options:
- 2
- 4
- 5
- 6


question: The output of the system has an effect upon the input quantity, then the system is a

options:
- open loop control system.
- closed loop control system.
- either A or B.
- none of the above.


question: A sinusoidal signal is analog signal, because

options:
- it can have a number of values between the negative and positive peaks
- it is negative for one half cycle
- it is positive for one half cycle
- it has positive as well as negative values


question: FM stands for

options:
- frequent modulation.
- frequency modulation.
- frequency moderator.
- frequent moderator.


question: Stack is also known as

options:
- FIFO memory
- Flash memory
- LIFO memory
- LILO memory


question: In Ward-Leonard system, the lower limit of the speed imposed by

options:
- Field resistance.
- Armature resistance.
- Residual magnetism of the generator.
- None of above.


question: Colpitts oscillator is also called as

options:
- Tank circuit oscillator
- LC oscillator
- Resonant circuit oscillator
- All of the above


question: An SCR has half cycle surge current rating of 3000 A for 50 Hz supply. One cycle surge current will be

options:
- 1500 A.
- 6000 A.
- 2121.32 A.
- 4242.64 A.


question: Both the ALU and control section of CPU employ which special purpose storage location?

options:
- Buffers
- Decoders
- Accumulators
- Registers


question: Systematic errors are

options:
- environmental errors.
- observational errors.
- instrument errors.
- all of the above.


question: Which of the following is/are the disadvantages of an open loop control system?

options:
- Inaccurate.
- Unreliable.
- both A and B.
- none of the above.


question: A diode (p-n junction) when reverse biased act as

options:
- On Switch
- Zener diode
- Capacitor
- Off Switch


question: Piezoelectric effect is carried out in

options:
- composite filter.
- crystal filter.
- m derived.
- constant k prototype.


question: The resistivity of the conductor depends on

options:
- area of the conductor.
- length of the conductor.
- type of material.
- none of these.


question: The smallest change in measured variable to which instrument will respond is

options:
- resolution.
- accuracy.
- precision.
- sensitivity.


question: In electronic communications, "AM" stands for

options:
- Amp Modification
- Amplitude Method
- Amplitude Modulation
- Ampere Method


question: Which system is also known as automatic control system?

options:
- Open loop control system
- Closed loop control system
- Either A or B
- Nether A nor B


question: A combinational PLD with a fixed AND array and a programmable OR array is called a

options:
- PLD
- PROM
- PAL
- PLA


question: A null type instrument as compared to a deflected type instrument has

options:
- a lower sensitivity.
- a faster response.
- a higher accuracy.
- all of the above.


question: Length of the cable is doubled, its capacitance C will be

options:
- one-fourth.
- one-half.
- doubled.
- unchanged.


question: Electrons in p-type material of a semi-conductor are called as

options:
- either minority carriers or majority carriers
- minority carriers
- majority carriers
- valance carriers


question: ________ is the most detrimental impurity in the magnetic materials

options:
- Carbon.
- Sulphur.
- Oxygen.
- Nitrogen.


question: Voltage controlled oscillators are used commonly in

options:
- Pulse Modulators Frequency Modulators Phase Clocked loops
- Frequency Modulators
- Phase Clocked loops
- All the above


question: Low frequency supply is necessary for direct core type induction furnaces because

options:
- With normal frequeny supply the electromagnetic forces causes severe stirring action in the molten metal.
- Magnetic coupling between the primary and secondary circuit is poor.
- Both A and B.
- None of the above.


question: The moving coil-meters, damping is provided by

options:
- the aluminium frame of the coil.
- the coil spring attached to the moving.
- eddy current disk.
- damping vane in the airtight chamber.


question: Which of the following is the analogous quantity for mass element in force-voltage analogy?

options:
- Resistance.
- Inductance.
- Capacitance.
- All of the above.


question: A latch is ________ sensitive

options:
- both level and edge
- edge
- level


question: What is used to protect the SCR from over current ?

options:
- CB and fuse.
- Heat sink.
- Snubber circuit.
- Voltage clamping device.


question: The errors mainly caused by human mistakes are

options:
- gross error.
- instrumental error.
- observational error.
- systematic error.


question: Electrical analogous quantity for dash-pot in force-current analogy is

options:
- resistance.
- conductance.
- inductance.
- capacitance.


question: Which lamp has the best Colour Rendering Index (CRI)?

options:
- LED
- Fluorescent
- Incandescent
- High pressure sodium vapour


question: Power dissipation in ideal inductor is

options:
- Maximum
- Minimum
- Zero
- A finite value


question: For intermittent work which of the following furnace is suitable?

options:
- Core less furnace.
- Indirect arc furnace.
- Either of above.
- Nither of above.


question: In electrical resistance welding material of electrode should have

options:
- higher electrical conductivities.
- higher thermal conductivities.
- sufficient strength to sustain high pressure at elevated temperatures.
- all of above.


question: Which of the following are the passive elements?

options:
- Resistor
- Bulb
- Both
- None of these.


question: The main advantage of dielectric heating is that

options:
- heating occurs in the material itself.
- heating occurs due to high frequency.
- it can be used for drying the explosives.
- None of the above.


question: Materials used in heat sink should have

options:
- high thermal conductivity.
- large surface area.
- high melting point.
- All of these.


question: Conductor is static and the field is varying then emf will be induced. This principle is called

options:
- virtually induced emf.
- dynamically induced emf.
- static induced emf.
- none of these


question: Four identical alternators each are rated for 20 MVA, 11 KV having a subtransient reactance of 16% are working in parallel. The short circuit level at the busbar is

options:
- 500 MVA
- 400 MVA
- 125 MVA
- 100 MVA


question: According to the Bohr model, an electron gains or losses energy only by

options:
- moving faster or slower in an allowed orbit.
- jumping from one allowed orbit to another.
- being completely removed from an atom.
- jumping from one atom to another atom.


question: A three-state buffer has the following output states

options:
- 1, 0, float
- High, Low, Float
- Both A and B
- Set, Reset, Halt


question: By using which of the following elements, mechanical translational systems are obtained?

options:
- mass element
- spring element
- dash-pot
- all of the above


question: Four capacitors each of 40 µF are connected in parallel, the equivalent capacitance of the system will be

options:
- 160 µF
- 10 µF
- 40 µF
- 5 µF


question: The resistance of a conductor of diameter d and length l is R Ω. If the diameter of the conductor is halved and its length is doubled, the resistance will be

options:
- R Ω
- 2R Ω
- 4R Ω
- 8R Ω


question: A single phase full bridge inverter can operated in load commutation mode in case load consist of

options:
- RL.
- RLC underdamped.
- RLC overdamped.
- RLC critically damped.


question: A microprocessor is ALU

options:
- and control unit on a single chip.
- and memory on a single chip.
- register unit and I/O device on a single chip.
- register unit and control unit on a single chip.


question: To obtain a high value of capacitance, the permittivity of dielectric medium should be

options:
- low
- zero
- high
- unity


question: Deflection method direct measurements are most widely used as these are

options:
- least time consuming.
- most simple.
- most simple and least time consuming.
- most accurate.


question: Purely mechanical instrument cannot be used for dynamic measurements because they have

options:
- high inertia.
- higher response time.
- large time constant.
- all of the above.


question: Advantages of higher transmission voltage is/are

options:
- Power transfer capability of the transmission line is increased
- Transmission line losses are reduced
- Area of cross section and volume of the conductor is reduced
- all of the above


question: Under over voltage condition impedance offered by the voltage clamping device is

options:
- high.
- low.
- moderate.
- infinity.


question: A long wire composed of a smooth round conductor runs above and parallel to the ground (assumed to be a large conducting plane). A high voltage exists between the conductor and the ground. The maximum electric stress occurs at

options:
- lower surface of the conductor.
- upper surface of the conductor.
- the ground surface.
- midway between the conductor and ground.


question: In a dc machine 6 pole wave winding is used. The number of parallel paths are?

options:
- 6
- 4
- 2
- 1


question: Which of the following is a digital device

options:
- Regulator of a fan
- Microphone
- Resistance of a material
- Light switch


question: Instantaneous power in inductor is proportional to the

options:
- product of the instantaneous current and rate of change of current.
- square of instantaneous current.
- square of the rate of change of current.
- temperature of the inductor.


question: Which of the following is a variable displacement transducer?

options:
- tachometer
- potentiometer
- synchros
- none of the above


question: Five capacitors each of 5 µF are connected in series, the equivalent capacitance of the system will be

options:
- 5 µF
- 25 µF
- 10 µF
- 1 µF


question: Susceptibility is negative for

options:
- non magnetic substances.
- diamagnetic substances.
- ferromagnetic substances.
- none of above.


question: One of the following is the primary function of an oscillator

options:
- produces sinusoidal oscillations
- generates non sinusoidal waveforms
- generates sustained oscillations at a constant amplitude and specific frequency
- none of the above


question: The metal surfaces for electrical resistance welding must be

options:
- rough.
- clean.
- moistened
- coloured


question: The latching current of SCR is 20 mA. Its holding current will be

options:
- 23 mA.
- 40 mA.
- 10 mA.
- 60 mA.


question: In force-current analogy, electrical analogous quantity for displacement (x) is

options:
- voltage.
- inductance.
- capacitance.
- flux.


question: Feedback circuit in an oscillator can be accomplished by

options:
- Resistive coupling between input and output
- Capacitive coupling between input and output
- Inductive coupling between input and output
- Any one or combinations of the above methods


question: Lowest critical frequency is due to zero and it may be present at the origin or nearer to the origin, then the type of network is

options:
- LC circuit.
- RC circuit.
- RLC circuit.
- RL Circuit.


question: What is the value of dielectric constant of air?

options:
- Less than 1
- 0.
- 1.
- none of these.


question: Temperature variation is a/an

options:
- Digital quantity
- Analog quantity
- Either Digital or Analog quantity


question: The illumination at a point 5 meters below a lamp in 6 lux. The candle power of the lamp is

options:
- 30
- 140.
- 150.
- 200.


question: For a dc machine shunt resistance and armature resistance values are

options:
- high and high
- high and low
- low and low
- low and high


question: The change of cross sectional area of conductor in magnetic field will affect

options:
- reluctance of conductor.
- resistance of conductor.
- (A) and (B) both in the same way.
- none of above.


question: Which of the following is used in SCR to protect from high dV / dt?

options:
- Snubber circuit.
- Fuse.
- Equalizing circuit.
- Circuit breaker.


question: What are the sets of commands in a program which are not translated into machine instructions during assembly process, called?

options:
- Mnemonics
- Directives
- Identifiers
- Operands


question: Speed of data transmission in 4-G network of telecom is

options:
- 386 kbps - 2 mbps.
- 2 mbps.
- 2 mbps – 1 gbps.
- 100 mbps - 1 gbps.


question: Which of the followings is/are active element?

options:
- Voltage source
- Current source
- Both
- None of these.


question: Electrical analogous quantity for spring element (K) in force-voltage analogy is

options:
- L
- R
- 1/C
- C


question: A quartz crystal oscillator consists of

options:
- only series resonant frequency.
- only parallel resonant frequency.
- both series and parallel frequencies.
- neither series nor parallel frequency.


question: Which of the following oscillators are used for low frequency (LF) applications

options:
- LC oscillators
- RC oscillators
- Both LC and RC Oscillators


question: The solid angle subtended by an area of 2400 cm^2 on the surface of a sphere of diameter 1.2 m is

options:
- 3 / 2.
- 1 / 3.
- 2 / 3.
- 2 / 5.


question: Relative error is same as

options:
- ratio of absolute error and true value.
- absolute error.
- true error.
- none of the above.


question: If holding current of a thyristor is 2 mA then latching current should be

options:
- 0.01 A.
- 0.002 A.
- 0.009 A.
- 0.004 A.


question: In an intel 8085A, which is the first machine cycle of an instruction?

options:
- An op-code fetch cycle
- A memory read cycle
- A memory write cycle
- An I/O read cycle


question: Which of the following are the disadvantages of a closed loop control system?

options:
- Reduces the overall gain.
- Complex and costly.
- Oscillatory response.
- All of the above.


question: Poles and zeros are arranged alternatively on negative real axis, then type of network is/are

options:
- LC network.
- RC network.
- RL network.
- Both 2 and 3.


question: The magnetisation and applied field in ferromagnetic materials are related

options:
- sinusoidally.
- non linearly.
- linearly.
- parabolically.


question: Thin laminations are used in a machine in order to reduce

options:
- Eddy current losses
- Hysteresis losses
- Both A and B
- Copper losses


question: A metal surface with 1 meter radius and surface charge density of 20 coulombs / m2 is enclosed in a 10 m side cube. The total outward electric displacement normal to the surface of the cube is

options:
- 40π coulombs.
- 80π coulombs.
- 10π coulombs.
- none of these.


question: In binary number system the first digit (bit) from right to left is called as

options:
- LSB, Least Significant Bit
- MSB, Most Significant Bit
- First Bit
- Last Bit


question: In two wattmeter method of power measurement if the total power is measured by one wattmeter only then power factor of the system is

options:
- 0.
- 0.5.
- 1.
- none of above.


question: A 0 - 100 V voltmeter has a guaranteed accuracy of 2 % of full scale reading. The voltage measured by the voltmeter is 75 V. The limiting error is in percentage

options:
- 3.33 %.
- 2.66 %.
- 2 %.
- 1 %.


question: Which of the following methods is/are used for reactive or voltage compensation

options:
- shunt capacitor
- series capacitor
- generation excitation control
- all of the above


question: The ROM programmed during manufacturing process itself is called

options:
- MROM
- PROM
- EPROM
- EEPROM


question: In 8085 name/names of the 16 bit registers is/are

options:
- stack pointer.
- program counter.
- both A and B.
- none of these.


question: Stability of a transmission line can be increased by

options:
- shunt capacitor
- series capacitor
- shunt reactor
- both A and B


question: Snubber circuit is used with SCR

options:
- in series.
- in parallel.
- either series or parallel.
- anti parallel.


question: The number of rings in the Bohr model of any element is determined by what?

options:
- Column number on periodic table.
- Atomic mass.
- Row number on periodic table.
- Atomic number.


question: Silicon and Germanium are ________ elements.

options:
- trivalant
- pentavalant
- hexavalant
- tetravalant


question: The number of output pins in 8085 microprocessors are

options:
- 27.
- 40.
- 21.
- 19.


question: If P is the power of a star connected system then what will be power of an equivalent delta connected system?

options:
- P
- 3P
- P/3
- None of the above


question: Which oscillators are easy to fabricate in a monolithic IC?

options:
- Crystal oscillator.
- Hartley oscillator.
- Wien bridge oscillator.
- Relaxation oscillator.


question: If all the elements in a particular network are linear, then the superposition theorem would hold, when the excitation is

options:
- DC only
- AC only
- Either AC or DC
- An Impulse


question: The feedback factor of a Wien bridge oscillator using Op-Amp is

options:
- 1/3
- 1/4
- 1/2
- 1


question: The length of bus cycle in 8086/8088 is four clock cycles, T1, T2, T3, T4 and an indeterminate number of wait state clock cycles denoted by Tw. The wait states are always inserted between

options:
- T1 & T2
- T2 & T3
- T3 & T4
- T4 & T1


question: Which of the following is not a sinusoidal oscillator?

options:
- LC oscillator
- RC phase shift oscillator
- Relaxation oscillator
- Crystal oscillator


question: A wire carrying current is bent in the form of a circular loop. Then the magnetic field around each portion of the wire will be

options:
- parallel to the plane of the wire.
- perpendicular to the circumference of the wire.
- parallel to half portion and perpendicular for the other half.
- none of above.