Wednesday, 12 July 2017

2015 GATE EE PAPER ANALYSIS

GATE 2015 Question Papers and Answer Keys 
[from organizing iit/iisc website]



SET 1 / MORNING SESSION                SET 2 / AFTERNOON SESSION


Detailed sollution by Gateforum
                                                           set 1           set 2


ANALYSIS

Forenoon Session/SET 1


SUBJECT
QUESTION NO
MARKS RELATED TO THAT QUESTION
TOTAL MARKS 
Network Theory 
2, 8, 9, 27, 51 & 55
3x1=3, 3x2=6
9
Control System
4, 6, 7, 33, 39, 42 & 44
3×1=3, 4×2=8
11
Signal & System
21, 34 & 43
1x1=1, 2×2=4
5
Digital Electronics
15, 26, 36 & 50
1×1=1, 3×2=6
7
Analog Circuits
1, 5, 16 & 32
3x1=3, 1x2=2
5
EMT
13, 14 & 53
2x1=2, 1x2=2
4
Measurements
12, 17 & 46
1×2=2, 2×1=2
4
Machines
19, 20, 23, 30, 35, 41 & 45
1×3=3 , 2×4=8
11
Power System
3, 18, 28, 29, 47 & 52
2×1=2, 4×2=8
10
Power Electronics
10, 37, 40, 48 & 49
1×1=1, 4×2=8
9
Mathematics
11, 22, 24, 25, 31, 38 & 54
4x1=4, 2x3=6
10
General Aptitude
1, 2, 3, 4, 5, 6, 7, 8, 9 & 10
5x1=5, 5x2=10
15



Afternoon Session/SET 2



SUBJECT
QUESTION NO
MARKS RELATED TO THAT QUESTION
TOTAL MARKS
Network Theory
8, 17, 20, 28, 35 & 55
3x1=3, 3x2=6
9
Control System
15, 23, 26, 30 & 41
2x1=2, 3x2=6
8
Signal & System
27, 34, 42 & 48
0x1=0, 4x2=8
8
Digital Electronics
13, 49 & 52
1x1=1, 2x2=4
5
Analog Circuits
1, 2, 3, 14, 22 & 32
5x1=5, 1x2=2
7
EMT


Measurements
10, 18 & 40
2x1=2, 1x2=2
4
Machines
9, 19, 21, 25, 31, 33, 36, 39, 44, 45 & 51
4x1=4, 7x2=14
18
Power System
4, 16, 24, 37, 43 & 46
3x1=3, 3x2=6
9
Power Electronics
50, 53 & 54
0x1=0, 3x2=6
6
Mathematics
5, 6, 7, 11, 12, 29, 38 & 47
5x1=5, 3x2=6
11
General Aptitude
1, 2, 3, 4, 5, 6, 7, 8, 9, 10
5x1=5, 5x2=10
15
Total
100

EE 2015 Analysis


Type of Questions asked from set 1 + set 2
 Networks
Two port networks, Thevinin's theorem
Basics of networks, Transient Analysis, Steady state analysis
Analog Circuits
Op-amp, FET amplifier, BJT Amplifier, Diode Circuits-Analysis and Application, Transistors

Digital Circuits
Flipflops, logic gates, Counters, Excitation machine, K-map, Boolean Algebra

Signals and Systems
Sampling, Filter, System analysis, Linear Time Invariant(LTI) Systems, Basics of signals and systems

Control Systems
 Nyquist plot, Root locus, Bode-plot, Stability & Routh Hurwitz Criterion, Feedback control systems, closed loop control systems, State space analysis, Signal flow graphs, Transfer Function

Electrical Machines
DC Machine, Transformer Losses, Induction Machine, Synchronous Machine, Special Machines

Power Systems
Load flow studies, GMR, per unit systems, 
Transmission Line, Economics of Power Generation, Fault analysis, Power Factor correction
Power Electronics
Phase controlled converters, 
Basics of Power Semiconductor Devices, Input power factor, Chopper, Inverters, buck boost chopper

Measurements
Frequency measurement, DVM, power factor measurement, energy meter, Error analysis, CRO, Wattmeter

Electromagnetic fileds
Dielectric field, spherical charge,
Electric Field, Magnetic field

Image-Analysis
SET-1
Aptitude Section: 
In aptitude section numerical and verbal aptitude questions were standard and as expected with an exception or two. its very easy to get 10-12 marks..
Technical SECTION
Most of the questions were straight forward with some theory questions from topics generally untouched by students during GATE Preparation and rest of the questions were either lengthy or non-trivial. Most questions required basic understanding of the core topics and a good analytical bent of mind.
The 2 marks questions were straight forward and were concept based – easily done if one read the questions properly. Machines were predominantly DC Machines questions that seemed tough on a first look but were easy if understood. Power Systems required good analytical grasp over the subject as the questions involved were non trivial and required a good amount of thinking.
Well some questions seemed tough and way out of my league. Maybe I would have left them if I were attempting the paper.
SET-2
Aptitude SECTION
In this section there was even distribution of Numerical and Verbal ability. Some questions in this paper turned to be outstanding and it would be easy to score 8 to 10 marks in this section.
TECHNICAL SECTION
1 Mark Questions   were pretty basic and needed clear calm thinking to figure the answers out. Some questions like the ones on Electric and Magnetic fields required the most basic understanding of the concepts studied maybe in Class XII. These concepts are easily forgotten by students and were completely unexpected in this question paper. Therefore they might have not been attempted by many students.
Overall the questions were concept oriented and not formula based; another new feature for GATE 2015. Machines again were DC Machine oriented questions that required just a bit of thinking to solve them.

2 Mark Questions questions seemed very basic and easy enough provided one devoted a bit of time to solve them. The questions from Electric and Magnetic Fields were good. One or two questions were such that it was difficult to place the chapters they are from.



Overall:
DC Machines questions dominated both sessions which was not as per expectations and not as per the normal trends. The Question Papers were more conceptual in nature than formula based. Overall, the papers featured a very good blend of conceptual and tricky questions along with pretty straight forward ones.

One can expect the cut offs to be lower than earlier years but I personally felt that this year’s papers were good and better than last year. The general consensus though amongst students is that it was a tough paper in all. So expect ranks to be better for the same marks when compared to last year.
Important topics from each subject based on weightage in GATE-2015 
  • Electrical Machines: Transformers and DC machines.
  • Engineering Mathematics: Graphs, functions, relations, mathematical logic, Linear Algebra, and Calculus.
  • Power Systems: Fault Calculations, Transients, Basics of Transmission & Distribution.
  • Control Systems: Time Domain Analysis, Root Locus and State variable Analysis.
  • Electric Circuits: KCL, KVL and Sinusoidal steady state Analysis.
  • Analog Electronics: OP-Amp and DC-biased BJTs
  • Digital Electronics: Boolean Algebra and Sequential Circuits
  • Power Electronics: Choppers and Rectifiers
  • Signals and Systems: Linear Time Invariant Systems and Z-Transform
NOTE:
  • Even a 1/3 mark will create big difference in your GATE Rank/Score. Never attempt any questions in which you are not confident.
  • Try to avoid answering questions based on your assumptions.
  • Never try to attempt questions from new topics, which you have never touched.
  • Every question is important whether it is a 1-mark or 2-mark.
  • Understand the question is important rather than answering the question in a hurry.

NOTE: all the informations collected from gate academy/ gateforum/ kreatryx  website

DIGITAL ELECTRONICS [ SYLLABUS ANALYSIS ]


NETWORK THEORY [SYLLABUS ANALYSIS]


Sunday, 9 July 2017

GATE 2018 Syllabus EE/ECE/IN

General Aptitude (GA): Common to All Papers

1. Verbal Ability: English grammar, sentence completion, verbal analogies, word groups, instructions, critical reasoning and verbal deduction.
2. Numerical Ability: Numerical computation, numerical estimation, numerical reasoning and data interpretation.

Electrical Engineering (EE)

Engineering Mathematics
Linear Algebra: Matrix Algebra, Systems of linear equations, Eigen values and eigen vectors.
Calculus: Mean value theorems, Theorems of integral calculus, Evaluation of definite and improper integrals, Partial Derivatives, Maxima and minima, Multiple integrals, Fourier Series. Vector identities, Directional derivatives, Line, Surface and Volume integrals, Stokes, Gauss and Green’s theorems.
 
Differential equations: First order equation (linear and nonlinear), Higher order linear differential equations with constant coefficients, Method of variation of parameters, Cauchy’s and Euler’s equations, Initial and boundary value problems, Partial Differential Equations and variable separable method.
Complex variables: Analytic functions, Cauchy’s integral theorem and integral formula, Taylor’s and Laurent’ series, Residue theorem, solution integrals.
Probability and Statistics: Sampling theorems, Conditional probability, Mean, median, mode and standard deviation, Random variables, Discrete and continuous distributions, Poisson,Normal and Binomial distribution, Correlation and regression analysis.
Numerical Methods: Solutions of non-linear algebraic equations, single and multi-step methods for differential equations.
Transform Theory: Fourier transform,Laplace transform, Z-transform.

Electric Circuits and Fields: 
Network graph, KCL, KVL, node and mesh analysis, transient response of dc and ac networks; sinusoidal steady-state analysis, resonance, basic filter concepts; ideal current and voltage sources, Thevenin’s, Norton’s and Superposition and Maximum Power Transfer theorems, two-port networks, three phase circuits; Gauss Theorem, electric field and potential due to point, line, plane and spherical charge distributions; Ampere’s and Biot-Savart’s laws; inductance; dielectrics; capacitance.
Signals and Systems: 
Representation of continuous and discrete-time signals; shifting and scaling operations; linear, time-invariant and causal systems; Fourier series representation of continuous periodic signals; sampling theorem; Fourier, Laplace and Z transforms.
Electrical Machines:
 Single phase transformer – equivalent circuit, phasor diagram, tests, regulation and efficiency; three phase transformers – connections, parallel operation; auto-transformer; energy conversion principles; DC machines – types, windings, generator characteristics, armature reaction and commutation, starting and speed control of motors; three phase induction motors – principles, types, performance characteristics, starting and speed control; single phase induction motors; synchronous machines – performance, regulation and parallel operation of generators, motor starting, characteristics and applications; servo and stepper motors.
Power Systems: 
Basic power generation concepts; transmission line models and performance; cable performance, insulation; corona and radio interference; distribution systems; per-unit quantities; bus impedance and admittance matrices; load flow; voltage control; power factor correction; economic operation; symmetrical components; fault analysis; principles of over-current, differential and distance protection; solid state relays and digital protection; circuit breakers; system stability concepts, swing curves and equal area criterion; HVDC transmission and FACTS concepts.
Control Systems: 
Principles of feedback; transfer function; block diagrams; steady-state errors; Routh and Niquist techniques; Bode plots; root loci; lag, lead and lead-lag compensation; state space model; state transition matrix, controllability and observability.
Electrical and Electronic Measurements:
 Bridges and potentiometers; PMMC, moving iron, dynamometer and induction type instruments; measurement of voltage, current, power, energy and power factor; instrument transformers; digital voltmeters and multimeters; phase, time and frequency measurement; Q-meters; oscilloscopes; potentiometric recorders; error analysis.
Analog and Digital Electronics:
 Characteristics of diodes, BJT, FET; amplifiers – biasing, equivalent circuit and frequency response; oscillators and feedback amplifiers; operational amplifiers – characteristics and applications; simple active filters; VCOs and timers; combinational and sequential logic circuits; multiplexer; Schmitt trigger; multi-vibrators; sample and hold circuits; A/D and D/A converters; 8-bit microprocessor basics, architecture, programming and interfacing.
Power Electronics and Drives: 
Semiconductor power diodes, transistors, thyristors, triacs, GTOs, MOSFETs and IGBTs – static characteristics and principles of operation; triggering circuits; phase control rectifiers; bridge converters – fully controlled and half controlled; principles of choppers and inverters; basis concepts of adjustable speed dc and ac drives.  

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Electronics and Communication Engineering (ECE)

Engineering Mathematics
Linear Algebra: Matrix Algebra, Systems of linear equations, Eigen values and eigen vectors.
Calculus: Mean value theorems, Theorems of integral calculus, Evaluation of definite and improper integrals, Partial Derivatives, Maxima and minima, Multiple integrals, Fourier Series. Vector identities, Directional derivatives, Line, Surface and Volume integrals, Stokes, Gauss and Green’s theorems.
 
Differential equations: First order equation (linear and nonlinear), Higher order linear differential equations with constant coefficients, Method of variation of parameters, Cauchy’s and Euler’s equations, Initial and boundary value problems, Partial Differential Equations and variable separable method.
Complex variables: Analytic functions, Cauchy’s integral theorem and integral formula, Taylor’s and Laurent’ series, Residue theorem, solution integrals.
Probability and Statistics: Sampling theorems, Conditional probability, Mean, median, mode and standard deviation, Random variables, Discrete and continuous distributions, Poisson,Normal and Binomial distribution, Correlation and regression analysis.
Numerical Methods: Solutions of non-linear algebraic equations, single and multi-step methods for differential equations.
Transform Theory: Fourier transform,Laplace transform, Z-transform.
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 usingLaplace 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 twin-tub 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 wave-shaping 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.
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Instrumentation Engineering (IN)


 Engineering Mathematics:
Linear Algebra: Matrix Algebra, Systems of linear equations, Eigen values and eigen vectors.
Calculus: Mean value theorems, Theorems of integral calculus, Evaluation of definite and improper integrals, Partial Derivatives, Maxima and minima, Multiple integrals, Fourier Series. Vector identities, Directional derivatives, Line, Surface and Volume integrals, Stokes, Gauss and Green’s theorems.
 
Differential equations: First order equation (linear and nonlinear), Higher order linear differential equations with constant coefficients, Method of variation of parameters, Cauchy’s and Euler’s equations, Initial and boundary value problems, Partial Differential Equations and variable separable method.
Complex variables: Analytic functions, Cauchy’s integral theorem and integral formula, Taylor’s and Laurent’ series, Residue theorem, solution integrals.
Probability and Statistics: Sampling theorems, Conditional probability, Mean, median, mode and standard deviation, Random variables, Discrete and continuous distributions, Poisson,Normal and Binomial distribution, Correlation and regression analysis.
Numerical Methods: Solutions of non-linear algebraic equations, single and multi-step methods for differential equations.
Transform Theory: Fourier transform,Laplace transform, Z-transform.

Electrical Circuits:

Voltage and current sources: independent, dependent, ideal and practical; v-I relationships of resistor, inductor, mutual inductor and capacitor; transient analysis of RLC circuits with dc excitation.
Kirchoff’s laws, mesh and nodal analysis, superposition, Thevenin, Norton, maximum power transfer and reciprocity theorems.
Peak-, average- and rms values of ac quantities; apparent-, active- and reactive powers; phasor analysis, impedance and admittance; series and parallel resonance, locus diagrams, realization of basic filters with R, L and C elements.
One-port and two-port networks, driving point impedance and admittance, open-, and short circuit parameters.

Signals and Systems:

Periodic, aperiodic and impulse signals; Laplace, Fourier and z-transforms; transfer function, frequency response of first and second order linear time invariant systems, impulse response of systems; convolution, correlation. Discrete time system: impulse response, frequency response, pulse transfer function; DFT and FFT; basics of IIR and FIR filters.

Control Systems:

Feedback principles, signal flow graphs, transient response, steady-state-errors, Bode plot, phase and gain margins, Routh and Nyquist criteria, root loci, design of lead, lag and lead-lag compensators, state-space representation of systems; time-delay systems; mechanical, hydraulic and pneumatic system components, synchro pair, servo and stepper motors, servo valves; on-off, P, P-I, P-I-D, cascade, feedforward, and ratio controllers. 

Analog Electronics:

Characteristics and applications of diode, Zener diode, BJT and MOSFET; small signal analysis of transistor circuits, feedback amplifiers. Characteristics of operational amplifiers; applications of opamps: difference amplifier, adder, subtractor, integrator, differentiator, instrumentation amplifier, precision rectifier, active filters and other circuits. Oscillators, signal generators, voltage controlled oscillators and phase locked loop.

 Digital Electronics

Combinational logic circuits, minimization of Boolean functions. IC families: TTL and CMOS. Arithmetic circuits, comparators, Schmitt trigger, multi-vibrators, sequential circuits, flip-flops, shift registers, timers and counters; sample-and-hold circuit, multiplexer, analog-to- digital (successive approximation, integrating, flash and sigma-delta) and digital-to-analog converters (weighted R, R-2R ladder and current steering logic). Characteristics of ADC and DAC (resolution, quantization, significant bits, conversion/settling time); basics of number systems, 8-bit microprocessor and microcontroller: applications, memory and input-output interfacing; basics of data acquisition systems.

Measurements

SI units, systematic and random errors in measurement, expression of uncertainty – accuracy and precision index, propagation of errors. PMMC, MI and dynamometer type instruments; dc potentiometer; bridges for measurement of R, L and C, Q-meter. Measurement of voltage, current and power in single and three phase circuits; ac and dc current probes; true rms meters, voltage and current scaling, instrument transformers, timer/counter, time, phase and frequency measurements, digital voltmeter, digital multimeter; oscilloscope, shielding and grounding.

Sensors and Industrial Instrumentation

Resistive-, capacitive-, inductive-, piezoelectric-, Hall effect sensors and associated signal conditioning circuits; transducers for industrial instrumentation: displacement (linear and angular), velocity, acceleration, force, torque, vibration, shock, pressure (including low pressure), flow (differential pressure, variable area, electromagnetic, ultrasonic, turbine and open channel flow meters) temperature (thermocouple, bolometer, RTD (3/4 wire),thermistor, pyrometer and semiconductor); liquid level, pH, conductivity and viscosity measurement.

Communication and Optical Instrumentation

Amplitude- and frequency modulation and demodulation; Shannon’s sampling theorem, pulse code modulation; frequency and time division multiplexing, amplitude-, phase-, frequency-, pulse shift keying for digital modulation; optical sources and detectors: LED, laser, photo-diode, light dependent resistor and their characteristics; interferometer: applications in metrology; basics of fiber optic sensing.

How does a Transformer work ?