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11th July 2015, 11:03 AM
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Re: Indian Engineering Services for ECE

You are looking for the details regarding the ECE subject of the Indian Engineering Services. SO I am providing it to you so that it may be helpful for you:


Paper – 1

1. Materials and Components:

Structure and properties of Electrical Engineering materials; Conductors, Semiconductors and Insulators, magnetic, Ferroelectric, Piezoelectric, Ceramic, Optical and Super-conducting materials. Passive components and characteristics Resistors, Capacitors and Inductors; Ferrities, Quartz crystal Ceramic resonators, Electromagnetic an Electromechanical components.

2. Physical Electronics, Electron Devices and ICs:

Electrons and holes in semiconductors, Carrier Statistics, Mechanism of current flow in a semiconductor, Hall effect; Junction theory; Different types of diodes and their characteristics; Bipolar Junction transistor; Field effect transistors; Power switching devices like SCRs, CTOs, power MOSFETs; Basics of ICs – bipolar, MOS and CMOS types; basic to Opto Electronics.

3. Signals and Systems

Classification of signals and systems: System modeling in terms of differential and difference equations; State variable representation; Fourier series; Fourier representation; Fourier series; Fourier transforms and their application to system analysis; Laplace transforms and their application to system analysis; Convolution and superposition integrals and their applications; Z-transforms and their Applications to the analysis and characterization of discrete time systems; Random signals and probability, Correlation functions; Spectral density; Response of linear system to random inputs.

4. Network theory

Network analysis techniques; Network theorems, transient response, steady state sinusoidal response; Network graphs and their applications in network analysis; Tellegen`s theorem. Two port networks; Z, Y h and transmission parameters. Combination of two ports, analysis of common two ports. Network functions: parts of network functions, obtaining a network function from a given part. Transmission criteria: delay and rise time, Elmore’s and other definitions effect of cascading. Elements of network synthesis.

5. Electromagnetic Theory

Analysis of electrostatic and magnetostatic fields: Laplace`s and Piossons’s equations; Boundary value problems and their solutions; Maxwell’s equations; application to wave propagation in bounded and unbounded media; Transmission lines: basic theory, standing waves, matching applications, misconstrue lines.Basics of wave guides and resonators; Elements of antenna theory.

6. Electronic Measurements and instrumentation

Basic concepts, standards and error analysis; Measurements of basic electrical quantities and parameters; Electronic measuring instruments and their principles of working: analog and digital, comparison, characteristics, application. Transducers; Electronic measurements of non electrical quantities like temperature, pressure, humidity etc; basics of telemetry for industrial use.


1. Analog Electronic Circuits:

Transistor biasing and stabilization. Small signal analysis. Power amplifiers. Frequency response. Wide banding techniques. Feedback amplifiers. Tuned amplifiers. Oscillators. Rectifiers and power supplies. Op Amp PLL, other linear integrated circuits and applications. Pulse shaping circuits and waveform generators.

2. Digital Electronic Circuits:

Transistor as a switching element; Boolean algebra, simplification of Boolean functions, Karnaguh map and applications; IC Logic gates and their characteristics; IC logic families: DTL, TTL, ECL, NMOS, PMOS and CMOS gates and their comparison; Combinational logic Circuits; Half adder, Full adder; Digital comparator; Multiplexer Demultiplexer; ROM and their applications. Flip flops. R-S, J.K, D and T flip-flops; Different types of counters and registers Waveform generators. A/D and D/A converters. Semiconductor memories.

3. Control Systems:

Transient and steady state response of control systems; Effect of feedback on stability and sensitivity; Root locus techniques; Frequency response analysis. Concepts of gain and phase margins: Constant-M and Constant-N Nichol’s Chart; Approximation of transient response from closed loop frequency response; Design of Control Systems, Compensators; Industrial controllers.

4. Communication Systems:

Basic information theory; Modulation and detection in analogue and digital systems; Sampling and data reconstructions; Quantization & coding; Time division and frequency division multiplexing; Equalization; Optical Communication: in free space & fiber optic; Propagation of signals oat HF, VHF, UHF and microwave frequency; Satellite Communication.

5. Microwave Engineering:

Microwave Tubes and solid state devices, Microwave generation and amplifiers, Waveguides and other Microwave Components and Circuits, Misconstrue circuits, Microwave Antennas, Microwave Measurements, Masers, lasers; Microwave propagation. Microwave Communication Systems terrestrial and Satellite based.

6. Computer Engineering:

Number Systems. Data representation; Programming; Elements of a high level programming language PASCAL/C; Use of basic data structures; Fundamentals of computer architecture; Processor design; Control unit design; Memory organization, l/o System Organisation. Microprocessors: Architecture and instruction set of Microprocessors 8085 and 8086, Assembly language Programming. Microprocessor Based system design: typical examples. Personal computers and their typical uses.

Sample Question Paper:

01. The threshold effect in demodulators is defined as

(a) The rapid fall of output SNR when the input SNR falls below a particular value
(b) Exhibited by all the demodulators when the input SNR is low
(c) Exhibited by all AM suppressed carrier coherent demodulators
(d) Exhibited by correlation receivers

Ans: (a)

02. An amplitude modulated signal is [ A + 0.5 A cos wm t] cos wct where wm and wc are respectively, modulating and carrier frequencies. The power efficiency is calculated to be

(a) 11.11%
(b) 0.25%
(c) 4.32%
(d) 50%

Ans: (a)

03. A 10-bit DAC provides an analog output which has a maximum value of 10.23 volts. Resolution of the DAC is

(a) 10 mV

IES Sample Paper for ECE

(b) 15 mV
(c) 20 mV
(d) 40 mV

Ans: (a)

04. in Communication Systems, noise due to quantization error is always

(a) Linear and signal dependent
(b) Non-linear and signal dependent
(c) Linear and signal independent at low frequencies only
(d) Non-linear and signal dependent at low frequencies only

Ans: (a)

05. 13dBm is equivalent to

(a) 2mW
(b) 20W
(c) 20mW
(d) 2MW

Ans: (c)

06. For an earth station transmitter, with an antenna output power of 40dBW (10,000W), a back-off loss of 3dB, a total branching and feeder loss of 3dB, a total branching and feeder loss of 3dB and transmit antenna gain of 4dB, the effective isotropic radiated power (EIRP) will be equal to

(a) 38dBW
(b) 40 dBW
(c) 36 dBW
(d) 47 dBW

Ans: (a)

07. A coherent binary phase-shift-keyed (BPSK) transmitter operates at a bit rate of 20Mbps. For a probability of error P (e) of 10-4 and given carrier-to-noise (C/N) density ratio of 8.8 dB, calculate energy of bit-to noise (Eb/N0) density ratio for a receiver bandwidth equal to the minimum double-sided Nyquist bandwidth?

(a) 23 dB
(b) 2.3 dB
(c) 8.8 dB
(d) 0.88dB

Ans : (c)

08. An elliptically (arbitrarily) polarized wave can be broken up into which of the following?

(a) Two circularly polarized components rotating in same direction
(b) Two circularly polarized components rotating in opposite directions
(c) Two stationary circularly polarized components
(d) None of these

Ans: (b)

09. The Klystron operation is based on the principle of

(a) Velocity modulation
(b) Amplitude modulation
(c) Frequency modulation
(d) Phase modulation

Ans: (a)

10. Which of the following is not an application of Varactor diode?

(a) Parametric amplifier
(b) Frequency tuner
(c) Voltage controlled oscillator
(d) Phase shifter

Ans: (d)


11. Which of the following quantity is not required in the calculation of Q of a cavity resonator?

(a) Energy stored
(b) Power dissipated
(c) Loss in radiation
(d) Dimensions of the cavity

Ans: (c)

12. When electromagnetic waves are propagated in a waveguide

(a) They travel along the walls of the waveguide
(b) They travel through the dielectric without touching the walls
(c) They are reflected from the walls but do not travel along the walls
(d) None of these

Ans: (b)

13. Slotted line with tuneable probe is not used to measure

(a) VSWR
(b) Wavelength
(c) Power
(d) Impedance

Ans: (c)

14. In a microwave magic-T, E plane and H plane are

(a) In phase
(b) Out of phase
(c) Isolated
(d) 900 out of phase

Ans: (c)

15. Both Baratters and bolometers are used for measurement of

(a) VSWR
(b) Transmission losses
(c) Microwave power
(d) Frequency

Ans: (c)

16. Magnetic properties of ferrites result mainly from

(a) Polarization of electromagnetic waves
(b) Dielectric behaviour of ferrite
(c) Magnetic dipole moment associated with the electron spin
(d) External magnetic fields

Ans: (c)

17. Time Division Multiplexing requires

(a) Constant data transmission
(b)Transmission of data samples
(c) Transmission of data at random
(d) Transmission of data of only one measurand

Ans: (b)

18. Random Satellite moves in

(a) Random paths
(b) Polar orbits
(c) Geostationary orbits
(d) Equatorial plane

Ans: (b)

19. An 8085 microprocessor executes the following instructions:
Two numbers are represented in signed 2’s complement form as
P = 11101101 and Q = 11100110
If Q is subtracted from P, the value obtained in signed 2’s complement form is

(a) 100000111
(b) 00000111
(c) 11111001
(d) 011111001

Ans: (b)

20. A radar receives an echo from a target 20 micro second after sending the signal. The approximate range of the target is?

(a) 300 m
(b) 3000 m
(c) 600 m
(d) 6000 m

Ans: (b)


21. A small code of 8085 as given below, is executed
The contents of the accumulator and flags after execution are

(a) A = DD, S = 1, Z = 0, CY = 0
(b) A = 7F, S = 1, Z = 0, CY = 1
(c) A = DD, S=0, Z= 1, CY =0
(d) A = 7F, S = 0, Z = 1, CY = 1

Ans: (b)

22. Following program finds absolute value of N:

ONE: (P)
The instructions of (P) and (Q) must be

(a) CMA and ADI 0H
(b) CMC and ADI 0H
(c) INR A and CMC
(d) INR A and CMA

Ans: (a)

23. An Intel 8085 processor is executing the program given below:
MVI A, 10H
MVI B, 10H
The number of times that the operation NOP will be executed as

(a) 1
(b) 2
(c) 3
(d) 4

Ans: (c)

24. Match List I with List II and select the correct answer using the code given below the lists:

List I List II

A. Immediate 1. LDA 30FF

B. Implicit addressing 2. MOV A, B

C. Register addressing 3. LXI H, 2050

D. Direct addressing 4. RRC



(a) 3 4 2 1
(b) 1 4 2 3
(c) 3 2 4 1
(d) 1 2 4 3

Ans: (a)

25. The average information associated with an extremely likely message is zero. What is the average information associated with an extremely unlikely message?

(a) Zero
(b) Infinity
(c) Depends on total number of messages
(d) Depends on speed of transmission of the message

Ans: (b)

26. For 8086 microprocessor, the jump distance in bytes for short jump range is equal to?

(a) Forward 255 and Backward 256
(b) Forward 127 and Backward 128
(c) Forward 31 and Backward 32
(d) Forward 15 and Backward 16

Ans: (b)

27. The action performed by the following instruction of 8086:

MOV [1234h], AX is?

(a) Move contents of memory location 1234h to register AX
(b) Move the contents of register AX to memory offset 1234h
(c) Add contents at 1234h and AX
(d) Add contents of 1234h and AX and store the result in 1234h

Ans: (b)

28. While executing a program, 8085 microprocessor completes fetching of instruction JMP 2050 stored at address 2057H. The contents of the program counter after fetching the Instruction would be?

(a) 2050H
(b) 2057 H
(c) 205A H
(d) 2051 H

Ans: (c)

29. What is fading?

(a) Change in polarization only at receiver end
(b) Change in frequency only at receiver end
(c) Fluctuation in signal strength at receiver
(d) Change in phase only at receiver

Ans: (c)


30. In a microprocessor, the service routine for a certain interrupt starts from a fixed location of memory which cannot be externally set, but the interrupt can be delayed or rejected. Such an interrupt is called?

(a) Non- mask able and non-vectored
(b) Mask able and non-vectored
(c) Non-mask able and vectored
(d) Mask able and vectored

Ans: (d)

31. A memory system has a total of 8 memory chips, each with 12 address lines and 4 data lines. The size of the memory system is then equal to?

(a) 16k bytes
(b) 32k bytes
(c) 48 k bytes
(d) 64k bytes

Ans: (a)

32. Consider the following statements for a DRAM:

1. Bit is stored as a charge.
2. It is made of MOS transistors.
3. Speed of DRAM is faster than processors.
4. Each memory cell requires six transistors
Which of these statements are correct?

(a) 1 and 2 only
(b) 2 and 3 only
(c) 3 and 4 only
(d) 1, 2, 3 and 4

Ans: (a)

33. The access time of a cache memory is 100ns and that of main memory is 1 ms.80% of the memory requests are for read and others are for write. Hit ratio for read only accesses is 0.9. A write through procedure is used. The average access time of the system for both read and writes requests are equal to?

(a) 200 ns
(b) 360 ns
(c) 720 ns
(d) 1100ns

Ans: (b)

34. a virtual memory system has an address space of 8 k words, a memory space of 4k words and page and block sizes of 1k words. The number of page faults using of 1k words. The number of page faults using LRU policy, for following page references is 10246215700

(a) 5
(b) 7
(c) 9
(d) 10

Ans: (a)

35. among following memory types, what is the abbreviation MPDRAM?

(a) Multi port Dynamic Random Access Memory
(b) Multipoint Dynamic Random Access Memory
(c) Multipoint Disk Random Access memory
(d) Multi port Dimensional Random Access memory

Ans: (a)

36. Which of the following register holds the instruction before it goes to the decoder:

(a) Control register
(b) Accumulator
(c) Address register
(d) Data register

Ans: (d)

37. The incorrect match (when n > 1) is

(a) SISD Model of computer: 1 control unit and 1 ALU
(b) SIMD Model of computer: 1 control unit and n ALUs
(c) MISD Model of computer: n control units and n ALUs
(d) MIMD model of computer: n control units and 1 ALU

Ans: (d)

38. In case the code is position dependent, then what is the most suitable addressing mode is

(a) Direct mode
(b) Indirect mode
(c) Relative mode
(d) Indexed mode

Ans: (c)

39. The data structure needed to convert infix notation to prefix notation is

(a) Queue
(b) Stack
(c) Tree
(d) Graph

Ans: (b)


40. An altimeter is basically

(a) a CW radar
(b) a FM radar
(c) a Doppler radar
(d) a device to indicate the direction at height

Ans: (a)

41. In locations where the humidity is low, ICs based on one of the following technologies should be handled only after grounding the body. What is the technology is

(a) TTL
(b) CMOS
(c) DTL
(d) I2L

Ans: (b)

42. Which of the following pulse modulation is analog?

(a) PCM
(b) Differential PCM
(c) PWM
(d) Delta

Ans: (c)

43. Which one of the following is correct? Energy of a power signal is

(a) finite
(b) zero
(c) infinite
(d) between 1 and 2

Ans: (c)

44. The figure of merit of a logic family is given by

(a) Gain bandwidth product
(b) (Propagation delay time) X (Power dissipation)
(c) (Fan-out) X (Propagation delay time)
(d) (Noise –margin) X (Power dissipation)

Ans: (b)

45. Considering the filtering property, the lead compensators and lag compensators are categorized respectively as

(a) Low pass and high pass filters
(b) High pass and low pass filters
(c) High pass and high pass filters
(d) Low pass and low pass filters

Ans : (b)

46. Binary data is being represented in size of byte and in 2’s complement form. The number of 0’s present in representation of (-127) DECIMAL is:

(a) 8
(b) 7
(c) 6
(d) 5

Ans: (c)

47. If both inputs of S-R NAND latch are low, the output will be

(a) Unpredictable
(b) Toggle
(c) Reset
(d) Remain same

Ans : (a)

48. The highest speed counter is

(a) Asynchronous counter
(b) Synchronous counter
(c) Ripple counter
(d) Ring counter

Ans: (b)

49. In the circuit shown, the need of the resistor RF is

(a) To increase the overall gain
(b) To stabilize the circuit
(c) To increase input impedance
(d) To prevent saturation

Ans: (b)


50. A 40V dc supply is connected across the network comprising of zener and silicon diode as shown. The regulated voltages V01, V02 and source current Is are

(a) 2.4V, 5.1 V and 21.7mA
(b) 3V, 6V and 22.7mA
(c) 3.3V, 9.3V and 20.5mA
(d) 4V, 10V and 20mA

Ans: (c)

51. For a full wave rectifier, with sinusoidal input and inductor as filter, ripple factor for maximum load current and minimum load current conditions are respectively equal to?

(a) 0.1 and 1
(b) 0.1 and 0.47
(c) 0 and 0.47
(d) 0 and 0.22

Ans: (c)

52. The second-harmonic component in the output of a transistor amplifier, without feedback, is B2. The second harmonic component, with negative feedback B2 is equal to (where A = Amplifier gain and b = feedback factor)

(a) B2/ 1 + Ab
(b) B2 (1 + Ab)
(c) B2/b
(d) B2/ Ab

Ans: (a)

53. A circuit which resonates at 1 MHz has a Q of 100. Bandwidth between half- power points is

(a) 10 kHz
(b) 100 kHz
(c) 10 Hz
(d) 100 Hz

Ans: (a)

54. An output signal of a power amplifier has amplitudes of 2.5V fundamental, 0.25V second harmonic and 0.1V third harmonics. The total percentage harmonic distortion of the signal is

(a) 12.8%
(b) 10.8%
(c) 6.4%
(d) 1.4%

Ans: (c)

55. A change in the value of the emitter resistance Re in a differential amplifier

(a) Affects the difference mode gain, Ad
(b) Affects the common mode gain, AC
(c) Affects both Ad and Ac
(d) Does not affect either Ad or Ac

Ans: (b)

56. In a transistor biased in the active region, thermal runway is due to

(a) Base emitter voltage VBE which decreases with rise in temperature
(b) Change in reverse collector saturation current due to rise in temperature
(c) Heating the transistor
(d) Changes in b which increases with temperature

Ans: (b)

57. A transistor is said to be useful to be configured as an amplifier when its b is equal to?

(a) less than 0
(b) Between 0 and 1
(c) Between 1 and 50
(d) > 50

Ans: (d)

58. A BJT is biased with a power supply of 12V. For minimum heat dissipation, the drop across the transistor will be equal to?

(a) 6V
(b) 9V
(c) 12V
(d) > 9V but < 12V

Ans: (a)

59. a bipolar junction transistor with forward current transfer ratio a= 0.98, when working in CE mode, calculate the current transfer ratio b as

(a) 98
(b) 0.02
(c) 49
(d) 0.49

Ans: (c)

60. Match List I with List II and select the correct answer using the code given below the lists:

List I List II

A. Tuned circuits 1. Schottky diode

B. Voltage reference 2. Varactor diode

C. High frequency switches 3. PIN diode

D. Current controlled attenuator 4. Zener diode



(a) 2 4 1 3
(b) 3 4 1 2
(c) 2 1 4 3
(d) 3 1 4 2

Ans: (a)

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