Source: http://jobsjobseverywhere.blogspot.in/search/label/Electronics%20interviews

ANALOG ELECTRONICS --PART I===========================1) How does a MOSFET work?2) What are different types of BJT configurations and when do we use them.3) What is the difference between TTL and CMOS ?4) What is noise margin?5) Which is the most important pin the micro-controller?6) Explain about Ground Bounce and Vcc Sag.7) What is EMI and what are different types of it.8) One question on any kind of sensors you are aware of Ex: hall sensor etc.9) What is LVDT.10) How do we select the correct value of decoupling capacitor (or) what is the purpose of using a decoupling capacitor.11) What is parasitic capacitance & what are the effects of it.12) What is the difference between microprocessor and microcontroller.13) What are different types of micro processor architectures14) What is the difference between bypass capacitor and decoupling capacitor15) How do you select an op amp (this can apply to other components also)16) Single ended and Differential signals.17) How do you decide the layer stack up on PCB.18) Questions from Filter Design: Analog and Digital Filters, different types of filters.19) What is signal integrity?20) What is meta stability?21) Difference between CPLD and FPGA22) Difference between DDR and DDR2 RAM.23) What is termination? What are the different types of terminations?24) When do you need to use an heat sink and how do you decide on that?25) What is the difference between clock buffer and clock driver?26) What is Jitter?27) What is gain bandwidth product?28) Define settling time of op amp?29) What is slew rate of op amp, define common mode rejection ratio and input offset voltage?30) What is the difference between static response and dynamic response?31) What is an integrator and differentiator?32) Define the parameters of an ADC or types of ADC etc?33) What is sample and hold circuit?34) What is a comparator? (some questions related to Schmitt trigger or positive feedback of op amp)35) What is Fan Out?36) Different types of Voltage regulators. (Linear, Switching etc..)37) How do you create a basic delay circuit?38) What is characteristic impedance?39) What is ringing, undershoot and overshoot of a signal why do they occur and how to reduce them?40) What are the parameters to be taken into consideration while selecting a mosfet?

DIGITAL ELECTRONICS TECHNICAL-INTERVIEW QUESTIONS -----------------------------------------------------------------------

What is the difference between a Flip-Flop and a Latch?

What is race around condition?

What is the VHF, UHF Frequency ranges?

What is Inter signal interference?

What is the difference between a synchronous and asynchronous circuit?Which is better?

What is the significance of excess 3 code? Explain Self-complementing property?

What is D-FF?

What are the different types of power amplifiers?

What is meant by Companding?

What is the basic difference between counters and registers?

What is a multiplexer?

How can you convert an SR Flip-flop to a JK Flip-flop?

How can you convert a JK Flip-flop to a D Flip-flop?

What is Race-around problem? How can you rectify it?

Which semiconductor device is used as a voltage regulator and why?

Explain an ideal voltage source?

Explain zener breakdown and avalanche breakdown?

What are the different types of filters?

What is the need of filtering ideal response of filters and actual response of filters?

What is sampling theorem?

What is impulse response?

Explain the advantages and disadvantages of FIR filters compared to IIR counterparts.

What is CMRR?

Explain half-duplex and full-duplex communication?

Which range of signals is used for terrestrial transmission?

Why is there need for modulation?

Which type of modulation is used in TV transmission?

Why we use vestigial side band (VSB-C3F) transmission for picture?

When transmitting digital signals is it necessary to transmit some harmonics in addition to fundamental frequency?

For asynchronous transmission, is it necessary to supply some synchronizing pulses additionally or to supply or to supply start and stop bit?

BPFSK is more efficient than BFSK in presence of noise. Why?

What is meant by pre-emphasis and de-emphasis?

Explain 3 dB cutoff frequency? Why is it 3 dB, not 1 dB?

Explain ASCII, EBCDIC?

COMMUNICATION INTERVIEW QUESTIONS----------------------------------------------------Important Topics---------------------------------

Analog Modulation

Amplitude Modulation

Frequency Modulation

Modulation Index,Bandwidth....

Nyquist Criteria for communication

Channel Capacity Theorem

Pulse Code Modulation

Adaptive Pulse Code Modulation

Differential Pulse Code Modulation

Radar Types

Primary and Secondary Radars

MDI

Frequency ranges- HF,VHF,UHF,Microwave….

Digital Modulation Techniques

FSK, PSK, QPSK, MSK, Gaussian MSK

Sample Questions

1. A 2MB PCM (pulse code modulation) has…

a) 32 channelsb) 30 voice channels & 1 signaling channel.c) 31 voice channels & 1 signaling channel.d) 32 channels out of which 30 voice channels, 1 signaling channel, & 1 synchronization channel.

Ans: (c)

2. Time taken for 1 satellite hop in voice communication is…

a) 1/2 secondb) 1 secondsc) 4 secondsd) 2 seconds

Ans: (a)

3. Max number of satellite hops allowed in voice communication is:

a) only oneb) more han onec) two hopsd) four hops

Ans: (c)

4. What is the maximal decimal number that can be accommodated in a byte?

a) 128b) 256c) 255d) 512

Ans: (c)

5. Conditional results after execution of an instruction in a micro processor is stored in…

a) registerb) accumulator

c) flag registerd) flag register part of PSW(Program Status Word)

Ans: (d)

6. Frequency at which VOICE is sampled is…

a) 4 KHzb) 8 KHzc) 16 KHzd) 64 KHz

Ans: (a)

7. Line of sight is…

a) Straight Lineb) Parabolicc) Tx & Rx should be visible to each otherd) none of the above

Ans: (c)

8. Purpose of PC(Program Counter) in a MicroProcessor is…

a) To store address of TOS(Top Of Stack)b) To store address of next instruction to be executed.c) count the number of instructions.d) to store base address of the stack.

Ans: (b)

9. What action is taken when the processor under execution is interrupted by a non-maskable interrupt?

a) Processor serves the interrupt request after completing the execution of the current instruction.b) Processor serves the interrupt request after completing the current task.c) Processor serves the interrupt request immediately.d) Processor serving the interrupt request depends upon the priority of the current task under execution.

Ans: (a)

10. The status of the Kernel is…

a) taskb) processc) not defined.d) none of the above.

Ans: (b)

11. What is the nominal voltage required in subscriber loop connected to local exchange?

a) +48 voltsb) -48 voltsc) 230 voltsd) 110 volts

12. To send a data packet using datagram , connection will be established…

a) before data transmission.b) connection is not established before data transmission.c) no connection is required.d) none of the above.

Ans: (c)

13. Word alignment is…

a) aligning the address to the next word boundary of the machine.b) aligning to an even boundary.c) aligning to a word boundary.d) none of the above.

Ans: (a)

14. When a C function call is made, the order in which parameters passed to the function are pushed into the stack is…

a) left to rightb) right to leftc) bigger variables are moved first than the smaller variales.d) smaller variables are moved first than the bigger ones.e) none of the above.

Ans: (b)

15. What is the type of signaling used between two exchanges?

a) inbandb) common channel signalingc) any of the aboved) none of the above.

Ans: (a)

16. Buffering is…

a) the process of temporarily storing the data to allow for small variation in device speedsb) a method to reduce cross talksc) storage of data within transmitting medium until the receiver is ready to receive.

d) a method to reduce routing overhead.

Ans: (a)

17. Memory allocation of variables declared in a program is…

a) allocated in RAM.b) allocated in ROM.c) allocated on stack.d) assigned to registers.

Ans: (c)

18. A software that allows a personal computer to pretend as a computer terminal is …

a) terminal adapterb) bulletin boardc) modemd) terminal emulation

Ans: (d)

8086 MICROPROCESSOR INTERVIEW QUESTIONS&ANSWERS----------------------------------------------------------------------

What is a Microprocessor?Microprocessor is a program-controlled device, which fetches the instructions from memory, decodes and executes the instructions. Most Micro Processor are single- chip devices.

What is the difference between microprocessor and microcontroller?The major difference is microprocessor doesn’t have inbuilt memory but micro-controller has inbuilt memory .In Microprocessor more op-codes, few bit handling instructions. But in Microcontroller: fewer op-codes, more bit handling Instructions. Micro-controller can be defined as a device that includes micro processor, memory, & input / output signal lines on a single chip.

Give examples for 8 / 16 / 32 bit Microprocessor?8-bit Processor - 8085 / Z80 / 6800;16-bit Processor - 8086 / 68000 / Z8000;32-bit Processor - 80386 / 80486.

Why 8085 processor is called an 8 bit processor?Because 8085 processor has 8 bit ALU (Arithmetic Logic Review).

Expand HCMOS?High-density n- type Complementary Metal Oxide Silicon field effect transistor.

What does microprocessor speed depend on?The processing speed depends on DATA BUS WIDTH.

What is the Maximum clock frequency in 8086?5 MHz is the Maximum clock frequency in 8086

Is the address bus unidirectional? Is the data bus is Bi-directional?The address bus is unidirectional because the address information is always given by the Micro Processor to address a memory location of an input / output devices.The data bus is Bi-directional because the same bus is used for transfer of data between Micro Processor and memory or input / output devices in both the direction.

What is the disadvantage of microprocessor?It has limitations on the size of data. Most Microprocessor does not support floating-point operations.

What is the difference between primary & secondary storage device?In primary storage device the storage capacity is limited. It has a volatile memory. In secondary storage device the storage capacity is larger. It is a nonvolatile memory. Primary devices are: RAM / ROM.Secondary devices are: Floppy disc / Hard disk.

Difference between SRAM and DRAM?Static RAM: No refreshing, 6 to 8 MOS transistors are required to form one memory cell, Information stored as voltage level in a flip flop.Dynamic RAM: Refreshed periodically, 3 to 4 transistors are required to form one memory cell, Information is stored as a charge in the gate to substrate capacitance.

What is an interrupt?Interrupt is a signal send by external device to the processor so as to request the processor to perform a particular work.

What are the different types of interrupts?Maskable and Non-maskable interrupts.

What is cache memory?Cache memory is a small high-speed memory. It is used for temporary storage of data & information between the main memory and the CPU (center processing unit). The cache memory is only in RAM.

Expand DMA?Direct Memory Access

Differentiate between RAM and ROM?RAM: Random Access Memory. Read / Write memory, High Speed, Volatile Memory. ROM: Read only memory, Low Speed, Non Volatile Memory

What is NV-RAM?Nonvolatile Read Access Memory, also called Flash memory.

What is a flag?Flag is a flip-flop used to store the information about the status of a processor and the status of the instruction executed most recently

What are the flags in 8086?

In 8086 Carry flag, Parity flag, Auxiliary carry flag, Zero flag, Overflow flag, Trace flag, Interrupt flag, Direction flag, and Sign flag.

What is meant by Maskable interrupt?An interrupt that can be turned off by the programmer is known as Maskable interrupt.

What is Non-Maskable interrupt?An interrupt which can be never be turned off (ie.disabled) is known as Non-Maskable interrupt.

Which interrupts are generally used for critical events?Non-Maskable interrupts are used in critical events. Such as Power failure, Emergency, Shut off etc.

Give examples for Maskable interrupts?RST 7.5, RST6.5, RST5.5 are Maskable interrupts

Give example for Non-Maskable interrupts?Trap is known as Non-Maskable interrupts, which is used in emergency condition.

What are the various segment registers in 8086?Code, Data, Stack, Extra Segment registers in 8086.

Which Stack is used in 8086?FIFO (First In First Out) stack is used in 8086.In this type of Stack the first stored information is retrieved first.

What is SIM and RIM instructions?SIM is Set Interrupt Mask. Used to mask the hardware interrupts.RIM is Read Interrupt Mask. Used to check whether the interrupt is Masked or not.

What is Tri-state logic?Three Logic Levels are used and they are High, Low, High impedance state. The high and low are normal logic levels & high impedance state is electrical open circuit conditions. Tri-state logic has a third line called enable line.

Give an example of one address microprocessor?8085 is a one address microprocessor.

In what way interrupts are classified in 8085?In 8085 the interrupts are classified as Hardware and Software interrupts.

What are Hardware interrupts?TRAP, RST7.5, RST6.5, RST5.5, INTR.

What are Software interrupts?RST0, RST1, RST2, RST3, RST4, RST5, RST6, RST7.

Which interrupt has the highest priority?TRAP has the highest priority.

Name 5 different addressing modes?Immediate, Direct, Register, Register indirect, Implied addressing modes.

How many interrupts are there in 8085?There are 12 interrupts in 8085.

What is the RST for the TRAP?RST 4.5 is called as TRAP.

In 8085 which is called as High order / Low order Register?Flag is called as Low order register & Accumulator is called as High order Register.

SAIL Interview questions & details for a Computer Science Candidate is given here...

The Interview will be about 30-40 minutes. There will be 4-5 members in the panel. One person will be from HR department .The questions can come from the entire span of engineering. But if you are a fresher, be prepared to explain about your engineering project in detail. For experienced people, if you are from related field of work, expect questions from your domain.

Some of the questions were...

What are the components of LAN?

How do we connect the systems in a LAN?

What is UTP? (Unshielded Twisted Pair)

How much distance it supports?

How much distance does a Fiber optic supports?

What is the throughput of the Ethernet LAN?

Describe about OSI Layers?

In which layer encryption can be done? And other than presentation layer?

What is the function of Bridge? Router?

Which layer is responsible for end 2 end connection?

What is RAID? (Redundant Array of Inexpensive Disks)

For what it is used for?

How can achieve fault tolerance through RAID?

Where the Static variable stored in C?

What are the functions of the OS?

Which OS you are familiar with?

What is the process?

What r its attributes?

How the process interacts with each others?

What r the mechanisms for inter process communication?

What is semaphore?

What is critical region?

How can semaphore avoid conflicts?

What is a virtual function?

What is late binding?

What is scope resolution operator?

Differentiate between testing and debugging?

Distinguish black box testing and white box testing?

What is unit testing?

How can u control the lost acknowledgement issue?

Is there is any difference between switch and hub? Which is good?

Principle behind the working of zener diode?

Give examples for 8 / 16 / 32 bit Microprocessors?

Why an 8 bit processor is called so?

Define HCMOS?

What is a Compiler?

Differentiate between Compiler and Interpretor?

What are the various interrupts in 8086? Explain each?

What is SIM and RIM instructions?

Leadership:

What do you prefer to be a team leader or team member?

What are the qualities you have for being a leader?

How can you solve the conflicts in a team?

How can you react if someone else competing with you in yourteam for promotion?

Can you tell me a instance in your college that insists your leadership attitude?

DRDO -Technical Paper------------------------------

The technical paper consists of 100 objective type questions covering the entire B-tech Syllabus.

Some questions from previous DRDO papers are given below---------------------------------------------------------------

What is the Maximum clock frequency in 8086?5 Mhz

What is Jitter?

Differentiate between static response and dynamic response?

If 100ns is Memory Access Time & 125 microsec is 1frame period. The no. of line that can besupported in a Time Divison Switch isa)125 Linesb)625 Linesc)525 Linesd)465 Lines

Explain noise margin in Amplifiers?

The no. of edges in disjoint Hamilton circuit in a complex graph with 17 edges isa) 8b) 9

c) 136d) 17^2

Assume a system has 16MB cache mean Disk Access Time & cache Access time is 76.5 ns & 1.5ns overall mean Access time us 465ms for each tripling the memory the miss rate is halved. The memory required to bring down the mean Access time to 24ns isa) 16 MBb) 24 MBc) 32 MBd) 48 MB

What are different types of micro processor architectures?

Average transfer speed of an i/p serial line is minimum 25,000 Bytes & maximum 60000 Bytes. Polling Strategy adopted takes 4 microsec (whether there is any i/p byte or not). It is assured that byte that retrieved from controller before next byte arrives are lost. Then the maximum safe polling interval isa) 12b) 12.33c) 12.67d) 32

Expand CPLD and FPGA.

A harddisk has a rotation speed of 4500RPM. then the latency time isa) .4b) .6c) .7d) .9

Suppose all elements above the principal diagonal od n x n matix A are zero. If non zero elements of the lower triangular Matrix is stored in an array B with A[1][1] stored at B[1]. The addressing formula to the nonzero element in A[i][j]=?a) A[i][j]b) i(j-1)/2 +ic) j(i-1)/2 +id) i(i-1)/2 +j

The minimum number of comparisons required to find the second smallest element in a 1000element array isa) 1008b) 1010c) 1999d) 2000

The internal path length of a Binary Tree with 10 nodes is 25. The external path length isa) 25b) 35c) 40d) 45

Average No. of Comparisons required to sort 3 elements isa) 2b) 2.33c) 2.67d) 3

In a switch the mean arrival rate of packets is 800 Packets/sec and the the mean service rate is925 Packets/seca) .008 Secb) .08 secc) .8 secd) 1.1 sec

What is Interface Control Information?

Expand HCMOS?ans.High-density n- type Complimentary Metal Oxide Silicon field effect transistor.

The minumum no. of Multiplications needed to compute x^768 isa) 9b) 10c) 425d) 767

Give examples for Maskable interrupts?ans.RST 7.5, RST6.5, RST5.5 are Maskable interrupts

Which of the following require a driver?DiskCacheRAMCPU

Explain the 4 segments of IP addresses.

DRDO Question Pattern

DRDO Scientist Entry Test(SET) is a 3 hour test.It consists of100 Technical Questions25 Genral Knowledge Questions25 Aptitude.

Technical Questions----------------------The technical questionnaire will be covering the entire engineering syllabus,whatever the stream you have applied for.It may contain questions from basic subjects to the advanced level.

So better use GATE coaching tests for the preparation.Electronics and Communication paper usually have the following specialized subjectsRadar and TelevisionSatellite communication,Electro magnetic and Antenna theory,Digital communication and filter designMicroprocessors.The questions from basic subjects like analog and digital electronics,networks will be usually easy but sometimes a little twisted.

Aptitude-----------The aptitude questions will be covering the usual topics likeRatio & ProportionTime and distance.Time and workProgression based questions.Simple geometry.Logarithms.Standard aptitude text books like Agarwaal is recommended.

General knowledge.----------------------A sample GK paper is posted recently in this site.Current affairs and general questions on history,geography,science etc are asked.Magazines like Competition Success Review,Year Books and GK related websites can be used.

Sample Questions of DRDO SET for E&C stream----------------------------------------------------1.The ethernet protocol usesa. CSMA/CAb.SCPCc.CSMA/CDd.Slotted ALOHA

2.A 1 kHz carrier is Amplitude Modulated to a depth of 60%.the total power of the modulated carrier isa.1kWb.1.06kWc.1.6kWd.1.18kW

3.A micro controller differs from microprocessor in terms ofa.I/O interfaces and memory configuration.b.Data bus width and clock speedc.memory configuration and instruction decoding.d.I/O interfaces and instruction decoding.

4.An inductance of 1H is realised using air core with 100 turns.What will be the inductance if the number of turns are doubled?a.1Hb.0.5Hc.2Hd.None of the above.

5.The divergence of magnetic flux density is

6.A straight line and a circle of radius r are given.a chord is drawn at random to this circle parallel to the given line.expected lenght of the chord oisa. 2ab.∏ac.∏a/2d.none

7.An inductor of inductance 0.1H,carrying a current of 6A will store energy ofa.6 Jb.36Jc.1.8Jd.3.6 J

8.When signal frequency is 2000KHz and IF is 455 KHz,the image frequency isa.2910KHzb.1645KHzc.2455KHzd.2090KHz

9.A source produces 4 symbols with a probability of 1/2,1/4,1/8,1/8.The avg. code word length is 2 bits/symbol.The efficiency of the code isa.1b.7/8c.1/2d.1/4

10.A man with n keys wants to open a lock.He tries his keys at random.The expected no. of attempts for his success isa.nb.n/2c.n^1/2d.none

11.In Radar equation,how the range depends upon frequency of the signal used.

12.The purpose of Cassegrain feed in parabolic reflector antenna is toa.Acheive higher antenna gainb.Reduce antenna sizec.Reduce beam-widthd.Ease of locating feed.

13.The advantage of ∏/4QPSK compared to conventional QPSKis

14.Unattenuated radiation field at the surface of the earth of a quarter-wave monopole will exist if the earth surface isa.Lossy dielectricb.Perfect insulatorc.Perfect conductord.None

15.What is the approximate skin depth in copper at 100MHz.a.0.1 micronb.10 micronc.10mmd.100 mm