CrazyEngineers Forum

CrazyEngineers Forum

Fixation of Motor to Wheel: Keyway or Flange?

Posted: 08 Jul 2011 02:04 PM PDT

Hi all,

I need some opinions about how to fix motor to wheel.
Is it better to mount it by keyway or using flange?

Thank you in advance

Need Suggestions for FYP on Image Processing

Posted: 08 Jul 2011 11:39 AM PDT

Hi Everyone!

I am a student of Electronics Engg. in 6th semester. I've to decide my FYP based on image processing applications. The application is to be implemented on any hardware platform like FPGAs, Texas DSP kits or using GPUs. I've already made a small project on target tracking through FPGA using real-time video processing. I need some latest ideas/research projects, any industry-specific or product-based project. I would be very glad and thankful if anyone could help me in this regard.

Thank you!

choosing the elective subjects

Posted: 08 Jul 2011 11:35 AM PDT

please help me in choosing the subjects: operating system,image processing(1 elective group) and out of real time systems and data structures(other electiv group) i am interested in the multimedia field . please help me in choosing the suitable elective

line follower robot

Posted: 08 Jul 2011 10:31 AM PDT

sir i want to maka a line follower robot using 8051 microcontroller .pls send me the assembly language program for tht and components required with making procedure.

NPTEL lectures

Posted: 08 Jul 2011 10:16 AM PDT

Sorry if it is a repost to someone, but wanted to share this link as there are lots of good lecture series uploaded on youtube by NPTEL, it may come handy sometimes:
YouTube - ‪nptelhrd's Channel‬‏

speed of bearing

Posted: 08 Jul 2011 07:39 AM PDT

Hi everybody.
I understand that bearing (a normal 10 $ ball bearing for example) .. can withstand limited speed (say 3000 rpm)
if spent at further speed then we should expect heating and wearing.
my question that if I had an application with higher speed. and I used two bearings one inside the other (outer diameter of smaller bearing goes inside the inner surface of larger bearing, or even through some spacing cylinder)..
would that get a speed range of multiplication of these two bearings .. and if not .. why ??:|

GATE 2012 Syllabus For Civil Engineering

Posted: 08 Jul 2011 06:49 AM PDT

Structural Engineering:-

Mechanics: Bending moments and shear forces in statically determinate beams -- simple stress and strain: relationship -- stress and strain in two dimensions, principal stresses, stress transformation, Mohr's circle -- simple bending theory -- flexural shear stress -- thin-walled pressure vessels -- uniform torsion.

Structural Analysis: Analysis of statically determinate trusses, arches and frames -- displacements in statically determinate structures and analysis of statically indeterminate structures by force/energy methods -- analysis by displacement methods (slope-deflection and moment-distribution methods) -- infludence lines for determinate and indeterminate structures -- basic concepts of matrix methods of structural analysis.

Concrete Structures: Basic working stress and limit states design concepts -- analysis of ultimate load capacity and design of members subject to flexure, shear, compression and torsion (beams, columns isolated footings) -- basic elements of prestressed concrete: analysis of beam sections at transfer and service loads.

Steel Structures: Analysis and design of tension and compression members, beams and beam-columns, column bases -- connections - simple and eccentric, beam-column connections, plate girders and trusses -- plastic analysis of beams and frames.

Geotechnical Engineering:-

Soil Mechanics: Origin of soils -- soil classification -- three-phase system, fundamental definitions, relationship and inter-relationships -- permeability and seepage -- effective stress principle: consolidation, compaction -- shear strength.

Foundation Engineering: Sub-surface investigation - scope, drilling bore holes, sampling, penetrometer tests, plate load test -- earth pressure theories, effect of water table, layered soils -- stability of slopes - infinite slopes, finite slopes -- foundation types - foundation design requirements -- shallow foundations -- bearing capacity, effect of shape, water table and other factors, stress distribution, settlement analysis in sands and clays -- deep foundations - pile types, dynamic and static formulae, load capacity of piles in sands and clays.

Water Resources Engineering:-

Fluid Mechanics and Hydraulics: Hydrostatics applications of Bernoulli equation, Laminar and turbulent flow in pipes, pipe networks -- concept of boundary layer and its growth -- uniform flow, critical flow and gradually varied flow in channels, specific energy concept, hydraulic jump -- forces on immersed bodies -- flow measurement in channels -- tanks and pipes -- dimensional analysis and hydraulic modeling.Applications of Momentum equation, Potential flow, Kinematics of flow -- Velocity triangles and specific speed of pumps and turbines.

Hydrology: Hydrologic cycle -- Rainfall -- evaporation infiltration, unit hydrographs, flood estimation, reservoir design, reservoir and channel routing, well hydraulics.

Irrigation: Duty, delta, Estimation of evapo-transpiration -- crop water requirements -- design of lined and unlined canals -- waterways -- head works, gravity dams and Ogee spillways.Designs of weirs on permeable foundation, Irrigation methods.

Environmental Engineering:-

Water Requirements -- quality and standards, basic unit processes and operations for water treatment, distribution of water. Sewage and sewerage treatment: Quantity and characteristic of waste water sewerage -- primary and secondary treatment of waste water -- sludge disposal -- effluent discharge standards.

Transportation Engineering:-

Highway planning -- Geometric design of Highways -- Testing and specifications of paving materials -- Design of flexible and rigid pavements.

GATE 2012 Syllabus For Manufacturing & Industrial Engineering

Posted: 08 Jul 2011 06:48 AM PDT

Engineering Materials:- Structure and properties of engineering materials and their applications, heat treatment. Metal Casting Casting processes (expendable and non-expendable) -pattern, moulds and cores, Heating and pouring, Solidification and cooling, Gating Design, Design considerations, defects.

Forming Processes:- Stress-strain diagrams for ductile and brittle material, Plastic deformation and yield criteria, Fundamentals of hot and cold working processes, Bulk metal forming processes (forging, rolling extrusion, drawing), Sheet metal working processes (punching, blanking, bending, deep drawing, coining, spinning, Load estimation using homogeneous deformation methods, Defects). Processing of Powder metals- Atomization, compaction, sintering, secondary and finishing operations. Forming and shaping of Plastics- Extrusion, Injection Molding.

Joining Processes:- Physics of welding, Fusion and non-fusion welding processes, brazing and soldering, Adhesive bonding, Design considerations in welding, Weld quality defects.

Machining and Machine Tool Operations:- Mechanics of machining, Single and multi-point cutting tools, Tool geometry and materials, Tool life and wear, cutting fluids, Machinability, Economics of machining, non-traditional machining processes.

Metrology and Inspection:- Limits, fits and tolerances, linear and angular measurements, comparators, gauge design, interferometry, Form and finish measurement, measurement of screw threads, Alignment and testing methods.

Tool Engineering:- Principles of work holding, Design of jigs and fixtures.

Computer Integrated Manufacturing:- Basic concepts of CAD, CAM and their integration tools.

Manufacturing Analysis:- Part-print analysis, tolerance analysis in manufacturing and assembly, time and cost analysis.

Work-Study:- Method study, work measurement time study, work sampling, job evaluation, merit rating.

Production Planning and Control:- Forecasting models, aggregate production planning, master scheduling, materials requirements planning.

Inventory Control:- Deterministic and probabilistic models, safety stock inventory control systems.

Operations Research:- Linear programming, simplex and duplex method, transportation, assignment, network flow models, simple queuing models, PERT and CPM.

js validation

Posted: 08 Jul 2011 06:19 AM PDT

get your source code for validation in a web page

GATE Syllabus 2012 for Electronics & Communication Engineering

Posted: 08 Jul 2011 06:17 AM PDT

Networks:

Network graphs: matrices associated with graphs; incidence, fundamental cut set and fundamental circuit matrices. Solution methods: nodal and mesh analysis. Network theorems: superposition, Thevenin and Norton's maximum power transfer, Wye-Delta transformation. Steady state sinusoidal analysis using phasors. Linear constant coefficient differential equations; time domain analysis of simple RLC circuits, Solution of network equations using Laplace transform: frequency domain analysis of RLC circuits. 2-port network parameters: driving point and transfer functions. State equations for networks.

Electronic Devices:

Energy bands in silicon, intrinsic and extrinsic silicon. Carrier transport in silicon: diffusion current, drift current, mobility, and resistivity. Generation and recombination of carriers. p-n junction diode, Zener diode, tunnel diode, BJT, JFET, MOS capacitor, MOSFET, LED, p-I-n and avalanche photo diode, Basics of LASERs. Device technology: integrated circuits fabrication process, oxidation, diffusion, ion implantation, photolithography, n-tub, p-tub and twintub CMOS process.

Analog Circuits:

Small Signal Equivalent circuits of diodes, BJTs, MOSFETs and analog CMOS. Simple diode circuits, clipping, clamping, rectifier. Biasing and bias stability of transistor and FET amplifiers. Amplifiers: single-and multi-stage, differential and operational, feedback, and power. Frequency response of amplifiers. Simple op-amp circuits. Filters. Sinusoidal oscillators; criterion for oscillation; single-transistor and op-amp configurations. Function generators and waveshaping circuits, 555 Timers. Power supplies.

Digital circuits:

Boolean algebra, minimization of Boolean functions; logic gates; digital IC families (DTL, TTL, ECL, MOS, CMOS). Combinatorial circuits: arithmetic circuits, code converters, multiplexers, decoders, PROMs and PLAs. Sequential circuits: latches and flip-flops, counters and shift-registers. Sample and hold circuits, ADCs, DACs. Semiconductor memories. Microprocessor(8085): architecture, programming, memory and I/O interfacing.

Signals and Systems:

Definitions and properties of Laplace transform, continuous-time and discrete-time Fourier series, continuous-time and discrete-time Fourier Transform, DFT and FFT, z-transform. Sampling theorem. Linear Time-Invariant (LTI) Systems: definitions and properties; causality, stability, impulse response, convolution, poles and zeros, parallel and cascade structure, frequency response, group delay, phase delay. Signal transmission through LTI systems.

Control Systems:

Basic control system components; block diagrammatic description, reduction of block diagrams. Open loop and closed loop (feedback) systems and stability analysis of these systems. Signal flow graphs and their use in determining transfer functions of systems; transient and steady state analysis of LTI control systems and frequency response. Tools and techniques for LTI control system analysis: root loci, Routh-Hurwitz criterion, Bode and Nyquist plots. Control system compensators: elements of lead and lag compensation, elements of Proportional-Integral- Derivative (PID) control. State variable representation and solution of state equation of LTI control systems.

Communications:

Random signals and noise: probability, random variables, probability density function, autocorrelation, power spectral density. Analog communication systems: amplitude and angle modulation and demodulation systems, spectral analysis of these operations, superheterodyne receivers; elements of hardware, realizations of analog communication systems; signal-to-noise ratio (SNR) calculations for amplitude modulation (AM) and frequency modulation (FM) for low noise conditions. Fundamentals of information theory and channel capacity theorem. Digital communication systems: pulse code modulation (PCM), differential pulse code modulation (DPCM), digital modulation schemes: amplitude, phase and frequency shift keying schemes (ASK, PSK, FSK), matched filter receivers, bandwidth consideration and probability of error calculations for these schemes. Basics of TDMA, FDMA and CDMA and GSM.

Electromagnetics:

Elements of vector calculus: divergence and curl; Gauss' and Stokes' theorems, Maxwell's equations: differential and integral forms. Wave equation, Poynting vector. Plane waves: propagation through various media; reflection and refraction; phase and group velocity; skin depth. Transmission lines: characteristic impedance; impedance transformation; Smith chart; impedance matching; S parameters, pulse excitation. Waveguides: modes in rectangular waveguides; boundary conditions; cut-off frequencies; dispersion relations. Basics of propagation in dielectric waveguide and optical fibers. Basics of Antennas: Dipole antennas; radiation pattern; antenna gain.

GATE Information Technology Sample Questions - II

Posted: 08 Jul 2011 06:12 AM PDT

1 In a population of N families, 50% of the families have three children, 30% of the families have two children and the remaining families have one child. What is the probability that a randomly picked child belongs to a family with two children?
A) 3/23
B) 6/23
C) 3/10
D) 3/5
Answer : (B)

2 Which one of the following is NOT shared by the threads of the same process ?
A) Stack
B) Address Space
C) File Descriptor Table
D) Message Queue
Answer : (A)

3 A subnet has been assigned a subnet mask of 255.255.255.192. What is the maximum number of hosts that can belong to this subnet?
A) 14.
B) 30
C) 62
D) 126
Answer : (C)

4 A software organization has been assessed at SEI CMM Level 4. Which of the following does the organization need to practice beside Process Change Management and Technology Change Management in order to achieve Level 5 ?
A) Defect Detection
B) Defect Prevention
C) Defect Isolation
D) Defect Propagation
Answer : (B)

5 Suppose that two parties A and B wish to setup a common secret key (D-H key) between themselves using the Diffle-Hellman key exchange technique. They agree on 7 as the modulus and 3 as the primitive root. Party A chooses 2 and party B chooses 5 as their respective secrets. Their D-H key is
A) 3
B) 4
C) 5
D) 6
Answer : (C)

6 We have two designs D1 and D2 for a synchronous pipeline processor. D1 has 5 pipeline stages with execution times of 3 nsec, 2 nsec, 4 nsec, 2 nsec and 3 nsec while the design D2 has 8 pipeline stages each with 2 nsec execution time. How much time can be saved using design D2 over design D1 for executing 100 instructions?
A) 214 nsec
B) 202 nsec
C) 86 nsec
D) -200 nsec
Answer : (A)

7 Which of the following statements is FALSE regarding a bridge
A) Bridge is a layer 2 device
B) Bridge reduces collision domain
C) Bridge is used to connect two or more LAN segments
D) Bridge reduces broadcast domain
Answer : (D)

8 What is the availability of a software with the following reliability figures?
Mean Time Between Failure (MTBF) = 25 days
Mean Time To Repair (MTTR) = 6 hours
A) 1%
B) 24%
C) 99%
D) 99.009%
Answer : (B)

9 In a particular Unix OS, each data block is of size 1024 bytes, each node has 10 direct data block addresses and three additional addresses: one for single indirect block, one for double indirect block and one for triple indirect block. Also, each block can contain addresses for 128 blocks. Which one of the following is approximately the maximum size of a file in the file system?
A) 512 MB
B) 2 GB
C) 8 GB
D) 16 GB
Answer : (D)

10 On a TCP connection, current congestion window size is Congestion Window = 4 KB. The window size advertised by the receiver is Advertise Window = 6 KB. The last byte sent by the sender is LastByteSent = 10240 and the last byte acknowledged by the receiver is LastByteAcked = 8192. The current window size at the sender is
A) 2048 bytes
B) 4096 bytes
C) 6144 bytes
D) 8192 bytes
Answer : (B)

11 Which of the following statements is TRUE about CSMA/CD
A) IEEE 802.11 wireless LAN runs CSMA/CD protocol
B) Ethernet is not based on CSMA/CD protocol
C) CSMA/CD is not suitable for a high propagation delay network like satellite network
D) There is no contention in a CSMA/CD network
Answer : (C)

12 How many pulses are needed to change the contents of a 8-bit upcounter from 10101100 to 00100111 (rightmost bit is the LSB)?
A) 134
B) 133
C) 124
D) 123
Answer : (B)

GATE Information Technology Sample Questions - I

Posted: 08 Jul 2011 06:10 AM PDT

1 A subnet has been assigned a subnet mask of 255.255.255.192. What is the maximum number of hosts that can belong to this subnet?
A) 14
B) 30
C) 62
D) 126
Answer : (C)

2 Which one of the following is NOT shared by the threads of the same process ?
A) Stack
B) Address Space
C) File Descriptor Table
D) Message Queue
Answer : (A)

3 Let G be a weighted undirected graph and e be an edge with maximum weight in G. Suppose there is a minimum weight spanning tree in G containing the edge e. Which of the following statements is always TRUE?
A) There exists a cutset in G having all edges of maximum weight.
B) There exists a cycle in G having all edges of maximum weight.
C) Edge e cannot be contained in a cycle.
D) All edges in G have the same weight.
Answer : (C)

4 A software organization has been assessed at SEI CMM Level 4. Which of the following does the organization need to practice beside Process Change Management and Technology Change Management in order to achieve Level 5 ?
A) Defect Detection
B) Defect Prevention
C) Defect Isolation
D) Defect Propagation
Answer : (B)

5 Suppose that two parties A and B wish to setup a common secret key (D-H key) between themselves using the Diffle-Hellman key exchange technique. They agree on 7 as the modulus and 3 as the primitive root. Party A chooses 2 and party B chooses 5 as their respective secrets. Their D-H key is
A) 3
B) 4
C) 5
D) 6
Answer : (C)

6 Consider the following message M = 1010001101. The cyclic redundancy check (CRC) for this message using the divisor polynomial x5 + x4 + x2 + 1 is :
A) 01110
B) 01011
C) 10101
D) 10110
Answer : (C)

7 Which of the following statements is FALSE regarding a bridge
A) Bridge is a layer 2 device
B) Bridge reduces collision domain
C) Bridge is used to connect two or more LAN segments
D) Bridge reduces broadcast domain
Answer : (D)

8 What is the availability of a software with the following reliability figures?
Mean Time Between Failure (MTBF) = 25 days
Mean Time To Repair (MTTR) = 6 hours
A) 1%
B) 24%
C) 99%
D) 99.009%
Answer : (B)

9 A channel has a bit rate of 4 kbps and one-way propagation delay of 20 ms. The channel uses stop and wait protocol. The transmission time of the acknowledgement frame is negligible. To get a channel efficiency of at least 50%, the minimum frame size should be
A) 80 bytes
B) 80 bits
C) 160 bytes
D) 160 bits
Answer : (D)

10 In a depth-first traversal of a graph G with n vertices, k edges are marked as tree edges. The number of connected components in G is
A) k
B) k+1
C) n-k-l
D) n-k
Answer : (C)

11 Which of the following statements is TRUE about CSMA/CD
A) IEEE 802.11 wireless LAN runs CSMA/CD protocol
B) Ethernet is not based on CSMA/CD protocol
C) CSMA/CD is not suitable for a high propagation delay network like satellite network
D) There is no contention in a CSMA/CD network
Answer : (C)

12 Which one of the following regular expressions is NOT equivalent to the regular expression (a + b + c)* ?
A) (a* + b* + c*)*
B) (a*b*c*)*
C) ((ab)* + c*)*
D) (a*b* + c*)*
Answer : (C)

GATE Electronics & Communication Engineering Sample Questions - IV

Posted: 08 Jul 2011 06:03 AM PDT

Q1 A circuit has a resistance of 11 W, a coil of inductive reactance 120 W, and a capacitor with a 120-W reactance, all connected in series with a 110-V, 60-Hz power source. What is the potential difference across each circuit element?

A) (a) VR = 110 V, (b) VL = VC = 1.2 Kv
B) (a) VR = 120 V, (b) VL = VC = 2.4 kV
C) (a) VR = 4.8 V, (b) VL = VC = 0 kV
D) (a) VR = 5.0 V, (b) VL = VC = 8.0 V

Q-2 Applying DeMorgan's theorem to the expression , we get
A) (A+B)+C
B) A(B + C)
C) Both A & B
D) None of above

Q-3 Express the decimal number 57 in binary.
A) 100101
B) 111010
C) 110010
D) 111001

Q-4 A vertical electric dipole antenna
a) radiates uniformly in all directions.
b) radiates uniformly in all horizontal directions, but more strongly in the vertical direction.
c) radiates most strongly and uniformly in the horizontal directions
d) does not radiate in the horizontal directions

Q-5 A particle oscillates according to the equation y=5.0 cos 23 t, where y is in centimeters. Find its frequency of oscillation and its position at t=0.15 s.

a) f = 23 Hz, y = -4.8 cm
B) f = 3.7 Hz, y = -5.0 cm
C) f = 3.7 Hz, y = -4.8 cm
D) f = 3.7 Hz, y = +4.8 cm

Q-6 A 10.0-µF capacitor is in series with a 40.0-W resistance, and the combination is connected to a 110-V, 60.0-Hz line. Calculate (a) the capacitive reactance, (b) the impedance of the circuit, (c) the current in the circuit, (d) the phase angle between current and supply voltage

A) (a) 0.0038W (b) 305W (c) 0.415 A (d) voltage lags by 8.58°
B) (a) 266W (b) 269W (c) 0.409 A (d) voltage lags by 81.4°
C) (a) 16 kW (b) 72 kW (c) 2.75 A (d) voltage lags by 6.63°
D) (a) 2.6 kW (b) 262W (c) 0.256 MA (d) voltage leads by 81.4°

Q-7 A circuit has a resistance of 11 W, a coil of inductive reactance 120 W, and a capacitor with a 120-W reactance, all connected in series with a 110-V, 60-Hz power source. What is the potential difference across each circuit element?

A) (a) VR = 110 V, (b) VL = VC = 1.2 Kv
B) (a) VR = 120 V, (b) VL = VC = 2.4 kV
C) (a) VR = 4.8 V, (b) VL = VC = 0 kV
D) (a) VR = 5.0 V, (b) VL = VC = 8.0 V

Q-8 What is the primary function of multiplexing?

A ) To match the frequency range of a signal to a particular channel.
B ) To reduce the bandwidth of a signal.
C ) To select one radio channel from a wide range of transmitted channels.
D ) To allow a number of signals to make use of a single communications channel.

Q-9 A second step to further increase system capacity is a digital access method called TDMA (Time Division Multiple Access). Using the same frequency channelization and reuse as FDMA analog but adding a time sharing element, the effective capacity is:

A) Doubled
B) Tripled
C) Reduced by one third
D) Unchanged

Q-10 What are Pseudo-Random noise sequences, or P/N Sequences?

A) P/N Sequences are known sequences which exhibit the properties or chracteristics of random sequences
B) P/N Sequences can be used to logically isolate users on the same physical (frequency) channel
C) P/N Sequences appear as random noise to everyone else, except to the transmitter and intended receiver
D) All of the above

Q-11 An op-amp integrator has a square-wave input. The output should be
A ) a sine wave.
B) a triangle wave
C) a square wave.
D) pure DC.

Q-12 What is the relationship between the series and parallel resonant frequencies of a quartz crystal?

A) They are equal.
B) Parallel resonant frequency is approximately 1 kHz higher than series resonant frequency
C) Series resonant frequency is approximately 1 kHz higher than parallel resonant frequency.
D) none of the above

Q-13 Which FET amplifier(s) has (have) a phase inversion between input and output signals?
A) common-gate
B) common-drain
C) common-source
D) all of the above

TRY TO FIND ANSWER TO ALL THE ABOVE QUESTIONS AND WRITE THEM IN REPLIES BELOW THIS.

GATE Electronics & Communication Engineering Sample Questions - III

Posted: 08 Jul 2011 05:58 AM PDT

1 The drain of an n-channel MOSFET is shorted to the gate so that VGS = VDS. The threshold voltage (VT) of MOSFET is 1 V. If the drain current (ID) is 1 mA for VGS = 2V, then for VGS = 3V, ID is
A) 2 mA
B) 3 mA
C) 9 mA
D) 4 mA
Answer : (D)

2 The first and the last critical frequency of an RC-driving point impedance function must respectively be
A) a zero and a pole
B) a zero and a zero
C) a pole and a pole
D) a pole and a zero
Answer : (D)

3 In what range should Re(s) remain so that the Laplace transform of the function e(a+2)t+5 exits?
A) Re (s) > a + 2
B) Re (s) > a + 7
C) Re (s) < 2
D) Re (s) > a + 5
Answer : (A)

4 A parallel plate air-filled capacitor has plate area of l0-4 m2 and plate separation of 10-3 m. It is connected to a 0.5 V, 3.6 GHz source. The magnitude of the displacement current is (e0 = 1/36p x 10-9 F/m)
A) 10 mA
B) 100 mA
C) 10 A
D) 1.59 mA
Answer : (A)

5 For the polynomial P(s) = s5 + s4 + 2s3 + 2s2 + 3s + 15, the number of roots which lie in the right half of the s-plane is
A) 4
B) 2
C) 3
D) 1
Answer : (B)

6 The phase velocity of an electromagnetic wave propagating in a hollow metallic rectangular waveguide in the TE10 mode is
A) equal to its group velocity
B) less than the velocity of light in free space
C) equal to the velocity of light in free space
D) greater than the velocity of light in free space
Answer : (D)

7 A device with input x(t) and output y(t) is characterized by: y(t) = x2(t). An FM signal with frequency deviation of 90 kHz and modulating signal bandwidth of 5 kHz is applied to this device. The bandwidth of the output signal is
A) 370 kHz
B) 190 kHz
C) 380kHz
D) 95kHz
Answer : (C)

8 The Q - meter works on the principle of
A) mutual inductance
B) self inductance
C) series resonance
D) parallel resonance
Answer : (C)

9 The Fourier transform of a conjugate symmetric function is always
A) imaginary
B) conjugate anti-symmetric
C) real
D) conjugate symmetric
Answer : (C)

10 An ideal op-amp is an ideal
A) voltage controlled current source
B) voltage controlled voltage source
C) current controlled current source
D) current controlled voltage source
Answer : (B)

GATE Electronics & Communication Engineering Sample Questions - II

Posted: 08 Jul 2011 05:55 AM PDT

1 A digital-to-analog converter with a full-scale output voltage of 3.5 V has a resolution close to 14m V. Its bit size is
A) 4
B) 8
C) 16
D) 32
Answer : (B)

2 A single-phase half-controlled rectifier is driving a separately excited dc motor. The dc motor has a back emf constant of 0.5 V/rpm. The armature current is 5 A without any ripple. The armature resistance is 2W. The converter is working from a 280 V, single phase ac source with a firing angle of 80°. Under this operating condition, the speed of the motor will be
A) 339 rpm
B) 359 rpm
C) 366 rpm
D) 386 rpm
Answer : (C)

3 In relation to the synchronous machines, which one of the following statements is false?
A) In salient pole machines, the direct-axis synchronous reactance is greater than the quadrature-axis synchronous reactance
B) The damper bars help the synchronous motor self start
C) Short circuit ratio is the ratio of the field current required to produce the rated voltage on open circuit to the rated armature current
D) The V-curve of a synchronous motor represents the variation in the armature current with field excitation, at a given output power
Answer : (C)

4 A parallel plate air-filled capacitor has plate area of l0-4 m2 and plate separation of 10-3 m. It is connected to a 0.5 V, 3.6 GHz source. The magnitude of the displacement current is (e0 = 1/36p x 10-9 F/m)
A) 10 mA
B) 100 mA
C) 10 A
D) 1.59 mA
Answer : (A)

5 The 8085 assembly language instruction that stores the content of H and L registers into the memory locations 2050H and 2051H, respectively, is
A) SPHL 2050H
B) SPHL2051H
C) SHLD 2050H
D) STAX 2050H
Answer : (C)

6 If E is the electric field intensity, Ñ(Ñ x E ) is equal to
A) E
B) | E |
C) null vector
D) zero
Answer : (D)

7 The insulation strength of an EHV transmission line is mainly governed by
A) load power factor
B) switching over-voltages
C) harmonics
D) corona
Answer : (B)

8 The Q - meter works on the principle of
A) mutual inductance
B) self inductance
C) series resonance
D) parallel resonance
Answer : (C)

9 A 800 kV transmission line is having per phase line inductance of 1.1 mH/km and per phase line capacitance of 11.68 nF/km. Ignoring the length of the line, its ideal power transfer capability in MW is
A) 1204 MW
B) 1504 MW
C) 2085 MW
D) 2606 MW
Answer : (C)

10 In a PCM system, if the code word length is increased from 6 to 8 bits, the signal to quantization noise ratio improves by the factor
A) 8/6
B) 12
C) 16
D) 8
Answer : (C)

11 At an industrial sub-station with a 4 MW load, a capacitor of 2 MVAR is installed to maintain the load power factor at 0.97 lagging. If the capacitor goes out of serivce, the load power factor becomes
A) 0.85
B) 1.00
C) 0.80 lag
D) 0.90 lag
Answer : (C)

12 The conduction loss versus device current characteristic of a power MOSFET is best approximated by
A) a parabola
B) a straight line
C) a rectangular hyperbola
D) an exponentially decaying function
Answer : (A)

13 High Voltage DC (HVDC) transmission is mainly used for
A) bulk power transmission over very long distances
B) inter-connecting two systems with the same nominal frequency
C) eliminating reactive power requirement in the operation
D) minimizing harmonics at the converter stations
Answer : (A)

14 For the equation,
s3 - 4s2+ s + 6 = 0
the number of roots in the left half of s-plane will be

A) 0
B) 1
C) 2
D) 3
Answer : (C)

15 For the function f(x) = x2 e-x, the maximum occurs when x is equal to
A) 2
B) 1
C) 0
D) -1
Answer : (B)