Wednesday 6 December 2017



Power Distribution Transformers are used to efficiently distribute
electricity from generating plants to industrial, commercial and residential areas.
Step-up transformers boost voltages up to 765,000 volts for easy transmission,
using small sized conductors. Step-down transformer are use to meet local higher current demands at 480, 277, 240, 208 and 120 volt requirements.

Autotransformers use one continuous winding through both the primary
and secondary on the same iron-core. The primary and secondary serve in the
same magnetic circuit causing current to flow in parts of the same winding. The main advantage of autotransformers are economical construction, and operating efficiency in low ratio situations like reduced-voltage motor starters.

Current Transformers (CT’s) are used when the a.c. currents are too large for measuring instruments such as power company kilowatt-hour meters. They work on the same principle as the clamp-on ammeter by sensing current flow through a conductor without having to break the circuit.

Constant-Current Transformers produce a constant secondary amperage to
a load even though the primary input amperage changes. By using a movable primary coil, air space between coils can be varied. This causes magnetic leakage
between the coils, and varies current flow in the secondary. A typical example of the use of these transformers are series street-lighting systems.

Thursday 30 November 2017



1.In which of the following base systems is 123 not a
valid number?
(a) Base 10
(b) Base 16
(d) Base 3

2. Storage of 1 KB means the following number of
(a) 1000
(d) 1064

3. What is the octal equivalent of the binary number:
(c) 572
(d) 573.

4. Pick out the CORRECT statement:
(a) In a positional number system, each symbol represents the
same value irrespective of its position
(b) The highest symbol in a position number system as a value
equal to the number of symbols in the system
(c) It is not always possible to find the exact binary
(d) Each hexadecimal digit can be represented as a sequence of
three binary symbols.

5.The binary code of (21.125)10 is
(a) 10101.001
(b) 10100.001
(c) 10101.010
(d) 10100.111.

6.A NAND gate is called a universal logic element
(a) it is used by everybody
(b) any logic function can be realized by NAND  gates alone
(c) all the minization techniques are applicable for optimum
NAND gate realization
(d) many digital computers use NAND gates.

7. Digital computers are more widely used as
compared to analog computers, because they are
(a) less expensive
(b) always more accurate and faster
(c) useful over wider ranges of problem types
(d) easier to maintain.

8. Most of the digital computers do not have floating
point hardware because
(a) floating point hardware is costly
(b) it is slower than software
(c) it is not possible to perform floating point addition by
(d) of no specific reason.

9. The number 1000 would appear just immediately
(a) FFFF (hex)
(b) 1111 (binary)
(c) 7777 (octal)
(d) All of the above.

10. (1(10101)2 is
(a) (37)10
(b) ( 69)10
(c) (41 )10
(d) — (5)10


 Microprocessor Interview Questions

Schmitt Trigger Interview Questions

Ultrasound Interview Questions

Embedded Systems Interview Questions

Motors Interview Questions

Basic Electrical Interview Questions

Basic Electrical Interview Questions 2

Top Electrical Interview Questions

Most Common Electronic Interview Questions

Electronic Circuits Interview Questions

Optical Electronic Interview Questions

Power Electronics Interview Questions

Instrumentation Interview Questions 2

Instrumentation Interview Questions 1

Instrument Transformer Interview Questions

Wednesday 29 November 2017


Interview questions and answers on... MICROPROCESSORS
1. The minimum number of transistors required to implement a 
two input AND gate is
A. 2
B. 4
C. 6
D. 8
Answer: C

2. Using DeMorgan’s Theorem we can convert any AND-OR 
structure into 
Answer: A

3. For a memory with a 16-bit address space, the addressability 
A. 16 bits
B. 8 bits
C. 2^16 bits
D. Cannot be determined
Answer: D 

4. Because we wish to allow each ASCII code to occupy one 
location in memory, most memories are _____ addressable. 
C. WORD (16 bits)
D. DOUBLEWORD (32 bits)
Answer: A

5. Circuit A is a 1-bit adder; circuit B is a 1 bit multiplier. 
A. Circuit A has more gates than circuit B
B. Circuit B has more gates than circuit A
C. Circuit A has the same number of gates as circuit B
(Hint: Construct the truth table for the adder and the multiplier)
Answer: A

6. When the write enable input is not asserted, the gated D latch 
______ its output. 
A. can not change
B. clears
C. sets
D. complements
Answer: A

7. A structure that stores a number of bits taken “together as a 
unit” is a 
A. gate
B. mux
C. decoder
D. register
Answer: D

8. We say that a set of gates is logically complete if we can build 
any circuit without using any other kind of gates. Which of the 
following sets are logically complete 
A. set of {AND,OR}
B. set of {EXOR, NOT}
C. set of {AND,OR,NOT}
D. None of the above
Answer: C

9. Of the following circuits, the one which involves storage is 
A. RS Latch
B. mux
C. nand
D. decoder
Answer: A

10. If the number of address bits in a memory is reduced by 2 
and the 
addressability is doubled, the size of the memory (i.e., thenumber of bits stored in the memory) 
A. doubles
B. remains unchanged
C. halves
D. increases by 2^(address bits)/addressability
Answer : C

Microprocessor Interview Questions

Schmitt Trigger Interview Questions

Ultrasound Interview Questions

Embedded Systems Interview Questions

Motors Interview Questions

Basic Electrical Interview Questions

Basic Electrical Interview Questions 2

Top Electrical Interview Questions

Most Common Electronic Interview Questions

Electronic Circuits Interview Questions

Optical Electronic Interview Questions

Power Electronics Interview Questions

Instrumentation Interview Questions 2

Instrumentation Interview Questions 1

Instrument Transformer Interview Questions

Thursday 23 November 2017



1. Which of the following is the first active satellite?
A. Echo I
B. Telstar I
C. Early Bird
D. Sputnik I

2.Which of the following is the first commercial satellite?
A. Early Bird
B. Telstar
C. Explorer
D. Courier

3. What is the first passive satellite transponder?
A. Sun
B. Early Bird
C. Score
D. Moon

4. The first satellite to receive and transmit simultaneously
A. Intelsat I
B. Agila I
C. Syncorn I
D. Telstar I

5. A helical antenna is used for satellite tracking because of
A. circular polarization
B. maneuverability
C. beamwidth
D. gain

6. Repeaters inside communications satellites are known as
A. Trancievers
B. Transponders
C. Transducers

7. Considered as the unsolved problem in satellite system
A. Coverage
B. Cost
C. Access
D. Privacy

8. ___________ is a satellite that rotates around the earth in a
low-altitude elliptical or circular pattern.
A. Geosynchronous satellite
B. Nonsynchronous satellite
C. Prograde satellite
D. Retrograde satellite

9. Is the geographical representation of a satellite antenna
radiation pattern
A. Footprint
B. Spot
C. Earth
D. Region

10. The smallest beam of a satellite antenna radiation pattern
A. Zone beam
B. Hemispheric beam
C. Spot beam
D. Global beam

11. A satellite beam that covers almost 42.4% of the earths
A. Zone beam
B. Hemispheric beam
C. Spot beam
D. Global beam

12. What is the frequency range of C-band?
A. 8.5 to 12.5 GHz
B. 3.4 to 6.425 GHz
C. 12.95 to 14.95 GHz
D. 27.5 to 31 GHz

13. A satellite signal transmitted from a satellite transponder to
earth’s station.
A. Uplink
B. Downlink
C. Terrestrial
D. Earthbound

14. Collects very weak signals from a broadcast satellite
A. Helical antenna
B. Satellite dish

15. What is a device that detects both vertically and horizontally
polarized signals simultaneously?
A. Orthomode transducer
B. Crystal detector
C. Optoisolator
D. Isomode detector

16. _________ detects the satellite signal relayed from the
feed and converts it to an electric current, amplifies and lower
its frequency.
A. Horn antenna
C. Satellite receiver
D. Satellite dish

17. Is a loss of power of a satellite downlink signal due to earth’s
A. Atmospheric loss
B. Path loss
C. Radiation loss

18. What height must a satellite be placed above the surface of
the earth in order for its rotation to be equal to earth’s rotation?
A. 26,426.4 miles
B. 27,426.4 miles
C. 23,426.4 miles
D. 22,426.4 miles

19. Point on the satellite obits closest to the earth.
A. Apogee
B. Perigee
C. Prograde
D. Zenith

20. The earth area covered by a satellite radio beam.
A. Beamwidth
B. Bandwidth
C. Footprint
D. Zone

21. What is the local oscillator (mixer) frequency of the satellite
with an uplink frequency in GHz band?
A. 3500 MHz
B. 4500 MHz
C. 2225 MHz
D. 2555 MHz

22. What kind of battery panels are used in some advance
A. Germanium based panels
B. Silicon based panel
C. Galium Phosphate solar panel array
D. Galium Arsenide solar panel array

23. Satellite engine uses
A. jet propulsion
B. ion propulsion system
C. liquid fuel
D. solar jet

24. A satellite batter has more power but lighter.
A. Lithium
B. Leclanche
C. Hydrogen
D. Magnesium

25. What kind of battery used by older satellites?
A. Lithium
B. Leclanche
C. Hydrogen
D. Magnesium

26. VSAT was made available in
A. 1979
B. 1981
C. 1983
D. 1977

27. What band does VSAT first operate?
A. L-band
B. X-band
C. C-band
D. Ku-band

33. The owner of AsiaSat 2 is
A. Asia Satellite Telecommunications Company (ASTC)
B. Japan Satellite System (JSAT)
C. China Great Wall Industry Corporation
D. Singapore Satellite Commision

34. What is the approximate path loss from satellite-to-earth
A. 100 dB
B. 150 dB
C. 175 dB
D. 200 dB

35. INTELSAT stands for
A. Intel Satellite
B. International Telephone Satellite
C. International Telecommunications Satellite
D. International Satellite

36. The frequency of Ku band for satellite communications.
A. 6/4 GHz
B. 14/11 GHz
C. 12/14 GHz
D. 4/8 GHz

37. A satellite cross-link means
A. Earth-to-satellite link
B. Satellite-to-earth link
C. Satellite-to-satellite link
D. None of these

38. Earth station uses what type of antenna
A. Despun antenna
B. Helical antenna
C. Toroidal antenna
D. Cassegrain antenna

39. What is the delay time for satellite transmission from earth
transmitter to earth receiver?
A. 0.5 s
B. 1.0 s
C. 5 ms
D. 0.25 ms

40. The bandwidth of C-band satellite frequency band in U.S.
A. 500 GHz
B. 1000 GHz
C. 1000 MHz
D. 500 MHz

41. The most common device used as an LNA is
A. zener diode
B. tunnel diode
D. Shockley diode

42. The radiation patterns of earth coverage antennas have abeamwidth of approximately
A. 21˚
B. 5˚
C. 17˚
D. 35˚

1. Sputnik I
2. Telstar
3. Early Bird
4. Telstar I
5. circular polarization
6. Transponders
7. Privacy
8. Nonsynchronous satellite
9. Footprint
10. Spot beam
11. Global beam
12. 3.4 to 6.425 GHz
13. Downlink
14. Satellite dish
15. Orthomode transducer
16. LNA
17. Path loss
18. 22,426.4 miles
19. Perigee
20. Footprint
21. 2225 MHz
22. Galium Arsenide solar panel array
23. ion propulsion system
24. Lithium
25. Hydrogen
26. 1979
27. C-band

33. China Great Wall Industry Corporation
34. 200 dB
35. International Telecommunications Satellite
36. 14/11 GHz
37. Satellite-to-satellite link
38. Cassegrain antenna
39. 0.5 s
40. 500 MHz
41. tunnel diode
42. 17˚

Tuesday 21 November 2017

Funny Interview Questions - Answer It In Your Way

Funny Interview Questions - Answer It In Your Way
Funny interview questions are popular with hiring managers because the way you answer provides some indication of your ability to do the job. They tend to remove tension and spark some discussion that isn't mainly focused on job. They test your ability to think, your creativity, your ability to remain calm. 
Whether you perceive brain teasers to be difficult or just a bunch of funny interview questions. The answers you provide will help the interviewers evaluate your problem-solving skills, critical thinking process, , and your ability to perform under stress. 

1.) If aliens landed in front of you and, in exchange for anything you desire, offered you any position on their planet, what would you want?- Infosys Technologies Ltd 

2.) You're a new addition to the crayon box, what color would you be and why?
-Capgemini India Pvt Ltd

3.) What is the funniest thing that has happened to you recently?- Tech Mahindra

4.) What's the last thing you watched on TV and why did you choose to watch it?- Microsoft India Pvt Ltd

5.) What's the most interesting thing about you that we wouldn't learn from your resume alone?- Tata Consultancy Services Ltd

6.) If you were the CEO of a company name one thing you would make compulsory in the office and one thing you would ban in the office?
- HCL Technologies Ltd

7.) What's the color of money?
- IBM India Pvt Ltd

Sunday 15 October 2017

Interview questions and answers on SCHMITT TRIGGER....

Interview questions and answers on SCHMITT TRIGGER....

1)what do mean by a Schmitt trigger?
Schmitt trigger is a type of comparator which uses positive feedback. Schmitt trigger convert an sinusoidal signal to a square wave signal.

2)how many types of Schmitt trigger used?
There are two types Schmitt trigger are used.
1. Inverting Schmitt trigger.
2. Non-inverting Schmitt trigger.

3)what do you mean by threshold voltage of Schmitt trigger?
The input voltage of Schmitt trigger for which the Schmitt trigger changes their output is called threshold voltage.

4)what do you mean by hysteresis of Schmitt trigger?
Hysteresis is the voltage difference between turn-on and turn-off voltage of comparator.



An ideal-opamp would have the following characteristics:-
1 Infinite voltage gain
2 Infinite input resistance
3 Zero o/p resistance
4 Zero o/p voltage when (i/p voltage is zero)
5 Infinite Band with
6 infinite common mode Rejection ratio
7 infinite slew rates.
2)what are the main features of Ics 741?
1 No external frequency compensation required.
2 short circuit protection.
3 offset null capability.
4 large common mode and differential voltage range
5 low power consumption
6 No latch up problem
3)what do you mean by differential input resistance?
differential input resistance is the equivalent resistance that can be measured at either the inverting and non inverting input terminal with the other terminal connected to ground.
4)what do you mean common mode rejection ratio (CMMR).
common mode rejection ratio define as “it is the ratio of the differential voltage Gain to the common mode gain of an op-amp.
CMMR= differential gain/ common mode gain
5)what do you mean by SVRR (supply voltage rejection ratio).
the change in an op-amp input –offset voltage, caused by variation in supply voltage is called supply voltage rejection ratio (SVRR).
6)what do you mean by slew rate of an op-amp.?
slew rate is the maximum rate of change of output voltage per unit of time.
7)what do you mean by an open loop configuration of an op-amp?
the open loop configuration of an op-amp indicate the No connection, exist between The output signal is not fed-back in any from into the input.
8)How many configuration in open-loop op-amp configuration?
there are three open-loop op-amp configurations:
1 Differential –amplifier.
2 Inverting amplifier
3 Non- inverting amplifier
9)what do you mean by voltage follower?
the lowest gain that can be obtained from a non-inverting amplifier with feed back Is 1. When the non-inverting amplifier is configured for unity, it is called a voltage Follower.
10)what do you mean by a comparator?
Comparator is an open-loop op-amplifier which compares the input voltage at other one terminal to a reference voltage at other terminal and produce a voltage at their output terminal.
11)what do you mean by a zero-crossing detector?
Zero-detector is a comparator in which a zero reference is applied at their non-inverting terminal. Zero-crossing detector switches their output from one state to another state if the input voltage crosses the zero point.
12)what do you mean by input offset current?
The algebraic difference between the current in the inverting terminals is as know as Input offset current.
13)what do you mean by input offset voltage?
Input offset voltage that must be applied between the two input terminal of an Op-amp to null the output.
14)what do you mean by input biased current?
input biased current is the average of the current that flow into the inverting and Non Inverting input terminals of the op-amps.


An ultrasound scan is a painless test that uses sound waves to create images of organs and structures inside your body. It is a very commonly used test. As it uses sound waves and not radiation, it is thought to be very safe. Doppler and duplex scans are used to visualise blood or fluids flowing through the body.

1)What is ultrasound?

Ultrasound is a high-frequency sound that you cannot hear but it can be emitted and detected by special machines.

2)How does ultrasound work?

Ultrasound travels freely through fluid and soft tissues. However, ultrasound bounces back (is reflected back) as echoes when it hits a more solid (dense) surface. For example, the ultrasound will travel freely though blood in a heart chamber. But, when it hits a solid valve, a lot of the ultrasound echoes back. Another example is that when ultrasound travels though bile in a gallbladder it will echo back strongly if it hits a solid gallstone.

So, as ultrasound 'hits' different structures of different density in the body, it sends back echoes of varying strength.

4)What does an ultrasound scan involve?*
You lie on a couch and an operator places a probe on your skin over the part of your body to be examined. The probe is a bit like a very thick blunt pen. Lubricating jelly is put on your skin so that the probe makes good contact with your body. The probe is connected by a wire to the ultrasound machine, which is linked to a monitor. Pulses of ultrasound are sent from the probe through the skin into your body. The ultrasound waves then bounce back as echoes from the various structures in the body.

The echoes are detected by the probe and are sent down the wire to the ultrasound machine. They are displayed as a picture on the monitor. The picture is constantly updated so the scan can show movement as well as structure. For example, the valves of a heart opening and closing during a scan of the heart. The operator moves the probe around over the surface of the skin to obtain views from different angles.

The scan is painless and takes about 15-45 minutes, depending on which parts of the body are being examined. A record of the results of the test can be made as still pictures or as a video recording.

4)What is an ultrasound test used for?
An ultrasound scan is a safe and painless test that creates images of organs and glands, abnormal lumps and other structures like muscles, tendons and joints. It is also used to check unborn babies during pregnancy.

It is used in many situations. The way the ultrasound bounces back from different tissues can help to determine the size, shape and consistency of organs, structures and abnormalities. So, it can:

Help to monitor the growth of an unborn child and check for abnormalities. An ultrasound scan is routine for pregnant women.Detect abnormalities of heart structures such as the heart valves. This type of ultrasound scan is called echocardiography. See the separate leaflet called Echocardiogram for more details.Help to diagnose problems of internal organs such as the:LiverGallbladderPancreasThyroid glandLymph nodesOvariesTestesKidneysBladderAppendixFor example, it can help to determine if an abnormal lump in one of these organs is a solid tumour or a fluid-filled cyst. Ultrasound also helps look for stones in the gallbladder or kidney.Help determine the nature of breast lumps. Ultrasound is one of the tests used to establish if a lump is non-cancerous (benign) or breast cancer.Help diagnose problems with muscles, tendons and joints. For example, ultrasound scans are used to help diagnose:Frozen shoulderTennis elbowMorton's neuromaCarpal tunnel syndromeDetect abnormal widening of blood vessels (aneurysms).Guide internal biopsies. A biopsy is a procedure in which a sample of tissue is taken. Some biopsies are taken using a thin needle, and the needle is guided to the right place with an ultrasound scan. For example, if you have a lump in your breast, you may have a sample of the lump taken away. The sample is then examined under the microscope to see if your lump is cancerous or not.

Some specialist ultrasound techniques

In some situations, a clearer picture can be obtained from a probe that is within the body. So a small probe, still attached by a wire to the ultrasound machine, can be:

Swallowed into the gullet (oesophagus). This may be used to obtain clearer images of the internal organs, particularly the stomach, upper gut and pancreas. See separate leaflet called Endoscopic Ultrasound Scan for more details.Placed in the vagina or rectum to obtain clearer images of inner organs, such as the womb (uterus), ovaries or prostate gland.Used to help guide a surgeon during an operation, in order to look deeper into structures.

Ultrasound may also be used for treating certain conditions, particularly those of muscles, tendons and joints. The scan may be used to guide an injection which can help to treat the problem. Doing the injection with the help of an ultrasound scan makes sure it reaches exactly the right place. For example, ultrasound-guided injections are a common way to treat shoulder problems such as a frozen shoulder.

The above are not exhaustive lists, and ultrasound scanning has various other uses.

5)What is a Doppler ultrasound scan?
A Doppler ultrasound records sound waves reflecting off moving objects, such as blood cells, to measure their speed and other aspects of how they flow through the body.

6)How does Doppler ultrasound work?
If the structure is moving then the echo comes back at a slightly different frequency (called the Doppler effect). This difference in frequency can be used to measure the speed of movement. Blood moving in an artery or vein causes small echoes and these are used to measure the speed of movement of the blood cells. The sound waves may be amplified though speakers. This allows the practitioner to listen to the flow of blood cells to determine whether or not there is normal flow. For example, listening to the flow of blood through the heart of a baby during a routine antenatal check-up. The sound waves may also be converted to colour pictures on a screen so that flow can be seen through the arteries or veins (colour Doppler). They may also be plotted on a graph showing changes in speed and direction (velocity).

What is Doppler ultrasound used for?
To listen to the heartbeat of an unborn baby (fetus) during pregnancy.To examine blood flow in arteries or veins in your arms or legs to see if you might have:Deep vein thrombosis.Peripheral arterial disease.Injury to your veins or arteries following trauma.

7)What does a Doppler ultrasound involve?
During pregnancy, the Doppler ultrasound is very similar to an ultrasound scan. A probe covered with gel is put on your skin over the pregnant womb (uterus). This is connected to a speaker. You and the practitioner are able to listen to the flow of blood through the baby's heart.

During a Doppler ultrasound of the arms and legs, blood pressure cuffs are placed along the thigh, calf, or ankle, or to different points along the arm. A paste is applied to the skin over the arteries being examined. Images are created as the probe is moved over each area.

8)What is a duplex ultrasound?
Duplex ultrasound is a special technique which combines traditional ultrasound with Doppler ultrasound. Images of the solid object being examined - for example, the artery and the blood flowing through it - are displayed on a screen or monitor. The object is usually grey and the blood flow is usually in colour (colour Doppler).

9)What is duplex ultrasound used for?
Duplex ultrasound is most commonly used to evaluate the blood flow in various arteries and veins in the body. The scan can help diagnose the following conditions:

Widening of the main artery in the tummy (abdominal aortic aneurysm). Ultrasound scans are used in the national screening programmes across the UK for abdominal aortic aneurysm.Blockage to an artery (an arterial occlusion).Blood clot.Blockage to the arteries in the neck (carotid occlusive disease).Renal duplex examines the kidneys and their blood vessels.Varicose veins.Venous insufficiency (a condition where veins have a problem sending blood back to the heart).

10)What does a duplex ultrasound involve?
This test is very similar to an ultrasound scan. A probe covered with gel is placed over the area to be examined. Images of the solid organ and the blood flowing through it are then seen on a monitor.

11)What should I do to prepare for these tests?
Usually there is no special preparation needed. Continue to take your usual medication. You should eat and drink normally before and after the test unless otherwise instructed. For example:

If certain parts of the tummy (abdomen) are being examined, you may be asked to eat a low-fibre diet for a day or so before the test (to minimise 'gas' in your gut).You may be asked not to eat for several hours before a scan of the abdomen.Occasionally for some scans, you may be given an enema to clear the bowel.To scan the bladder or pelvis, you may be asked to drink some fluid before the test so that you have a full bladder. This is particularly likely if you are having a scan in pregnancy, or a scan of your ovaries or womb (uterus).

You will be told what you need to do before any particular scan.

12)Are there any side-effects or complications from ultrasound, Doppler or duplex scans?

These scans are painless and safe. Unlike X-rays and other imaging tests, they do not use radiation. They have not been found to cause any problems or complications.


1)Define Embedded Systems.
An embedded system is one that has computer-hardware with software embedded in it as one of its most important component. Software embedded into hardware is known as embedded systems.
E.g: Mobile Phones, Elevator, Computer, etc….
2)What are the components of embedded system hardware?
- Processor
- Program memory and data memory
- Timers
- Serial communication ports
- Input devices
- Output devices
- Power suply, Reset and Oscillator Circuits
3)Classification of embedded system.
ans. - Small Scale Embedded Systems
- Medium Scale embedded Systems
- Large Scale Embedded Systems
4)Define Processor.
Processor is the heart of the system. A processor implements a process or processes as per the commands given to it.
Specify the 2 essential units of the processor in a system.
. - Program Flow Control Unit (CU)
- Execution Unit (EU)
5)What are the types of General Purpose Processor?
. - Microprocessor
- Microcontroller
- Embedded Processor
- Digital Signal Processor (DSP)
- Media Processor
6)Define Microprocessor.
A microprocessor is a single VLSI chip that has a CPU and may also have some other units that are additionally present and that result in faster processing of instructions.
7)Define Microcontroller.
A microcontroller is a single-chip VLSI unit which, though having limited computational capabilities, possesses enhanced input-output capabilities ana a number of on-chip functional units.
8)What is Clock?
A fixed frequency pulses that an oscillator circuit generates and that controls all operations during processing and all timing references of the system.

Interview questions and answers on MOTORS...

Interview questions and answers on MOTORS...
An AC motor is an electric motor driven by an alternating current (AC). It commonly consists of two basic parts, an outside stationary stator having coils supplied with alternating current to produce a rotating magnetic field, and an inside rotor attached to the output shaft that is given a torque by the rotating field.

A DC motor is a mechanically commutated electric motor powered from direct current (DC). The stator is stationary in space by definition and therefore so is its current. The current in the rotor is switched by the commutator to also be stationary in space. This is how the relative angle between the stator and rotor magnetic flux is maintained near 90 degrees, which generates the maximum torque.

1. Low cost,
2. long life,
3. high efficiency,
4. large ratings available (to 1 MW or more),
5. large number of standardized types.
Disadvantages of AC Motors:
1. Starting inrush current can be high,
2. speed control requires variable frequency source.
Advantages of DC Motors:
1. Precision positioning,
2. High holding torque,
3. Long lifespan,
4. Low maintenance,
5. High efficiency
Disadvantages of DC Motors:
1. Some can be costly,
2. Require a controller,
3. Higher initial cost,
4. Requires a controller.

A series-wound motor is known as a universal motor when it has been designed to operate on either AC or DC power. It operate well on AC because the current in both the field and the armature (and hence the resultant magnetic fields) will alternate in synchronism and hence, the resulting mechanical force will occur in a constant direction of rotation.

The following are major designs and manufacturing standards covering electric motors:
International Electro-technical Commission: IEC 60034 Rotating Electrical Machines
National Electrical Manufacturers Association (USA): NEMA MG 1 Motors and Generators
Underwriters Laboratories (USA): UL 1004 – Standard for Electric Motors

6)What is the back emf ?*
ans. When the motor armature continues to rotate due to motot action the armature conductor cuts te magentic flux, and therefore emf are induced in them the direction of this induced emf is such that it oppose the applied voltage therefore this is called Back emf. .

7)What is a stepper motor for?*
Stepper motors are DC motors that move in discrete steps. They have multiple coils that are organized in groups called "phases". By energizing each phase in sequence, the motorwill rotate, one step at a time. With a computer controlled stepping you can achieve very precise positioning and/or speed control.

8)What are the types of stepper motors?*
Permanent magnet stepper.
Hybrid synchronous stepper.
Variable reluctance stepper.

9)How do you control a stepper motor?*
Stepper motors can move an exact amount of degrees (or steps) when told to do so. This gives you total control over the motor, allowing you to move it to an exact location and hold that position. It does so by powering coils inside the motor for very short periods of time.

10)What is the use of stepper motor driver?
The EasyDriver is a simple to use stepper motor driver, compatible with anything that can output a digital 0 to 5V pulse (or 0 to 3.3V pulse if you solder SJ2 closed on the EasyDriver). The EasyDriver requires a 6V to 30V supply to power the motor and can power any voltage of stepper motor 

11)What are the advantages of a stepper motor?*
Advantages of step motors are low cost, high reliability, high torque at low speeds and a simple, rugged construction that operates in almost any environment. The main disadvantages in using a stepper motor is the resonance effect often exhibited at low speeds and decreasing torque with increasing speed.

12)What is the difference between a stepper motor and a servo motor?*
Stepper vs Servo. The basic difference between a traditional stepper and a servo-based system is the type of motor and how it is controlled. ... Steppers don't require encoders since they can accurately move between their many poles whereas servos, with few poles, require an encoder to keep track of their position.

13)How does a stepper motor controller work?*
First is the pulse generator, also known as a stepper motor controller or indexer. ... A step motor has two primary parts; the rotor, the moving piece, and the stator, the stationary piece. The stator contains coils of wire called windings. The rotor spins on bearings or bushings inside the stator.

14)Where is a stepper motor used?*
Today, stepper motor applications are all around us: they are used in printers (paper feed, print wheel), disk drives, clocks and watches, as well as used in factory automation and machinery. A stepper motor is most often found in motion systems requiring position control.

15)How does it work stepper motor?*
Stepper motors consist of a permanent magnetic rotating shaft, called the rotor, and electromagnets on the stationary portion that surrounds the motor, called the stator. Figure 1 illustrates one complete rotation of a stepper motor. ... You may double the resolution of some motors by a process known as "half-stepping".



*What do you mean by an instrument transformer?
Transformer which is used with measuring instrument is called instrument transformers. Instrument transformer is used as a protection circuit of power system for the operation of over current, under voltage, Earth fault etc.

*what are the types of instrument transformer?
there are two types of instrument transformer:
1. Current transformer- used to measure current
2. Voltage transformer - to measure voltage

*what are the Advantages of instrument transformer?
Advantages of instrument transformer are:
1. Instrument transformer s are moderate in size and used for 5A current and 100 to 200 V measurement.
2. Instruments using instrument transformer are low cost.
3. Replacement of damage parts is Easy.
4. The metering circuit is isolated the high voltage power circuit hence insulation and safety is assured for operation.
5. There is low power consumption in metering circuit.

*what do you mean by a phase Angel of instrument transformer?
The angle between secondary current and primary current of a current transformer is called phase angle of instrument transformer.

*what do you mean by transformation ratio of instrument transformer?
It is the ratio of primary winding current to the secondary winding current of an instrument transformer.

*what do you mean by Nominal ratio of instrument transformer?
It is the ratio of rated primary winding current to the rated secondary winding current of an instrument transformer.

*what do you mean by ratio correction factor of instrument transformer?
It is the ratio of the transformation ratio to the nominal ratio of an instrument transformer

Monday 18 September 2017

Interview questions and answers on DIP

Interview questions and answers on DIP
1)*What is Digital Image?*
A digital image is a representation of a two-dimensional image as a finite set of digital values, called picture elements or pixels

2)*What is DIP?*
Digital image processing focuses on two major tasks
Improvement of pictorial information for human interpretation
Processing of image data for storage, transmission and representation for autonomous machine perception
Some argument about where image processing ends and fields such as image analysis and computer vision start.
The continuum from image processing to computer vision can be broken up into low-, mid- and high-level processes

3)*What is the use of DIP?*
The use of digital image processing techniques has exploded and they are now used for all kinds of tasks in all kinds of areas
Image enhancement/restoration
Artistic effects
Medical visualisation
Industrial inspection
Law enforcement
Human computer interfaces

Thursday 14 September 2017

Cathode Ray Oscilloscope (CRO) Questions and Answers

Cathode Ray Oscilloscope (CRO) Questions and Answers
1. Explain what is a cathode ray oscilloscope (CRO)?
A CR0 is an electronic device with a CRT as its main component and other associated circuits consisting of a power supply unit, a sawtooth-wave generator, horizon and vertical amplifiers .

2. How is CRO superior to ordinary measuring instruments?
CR0 is an electronic device that gives graphical representation of alternating quantities under examination. The CR0 gives very accurate measurements and is free from the errorsintroduced by the moving parts. It is also from damping mechanisms and other containing parts.

3. For Explain what vertical and horizontal plates are provide in a CRO?
Horizontal and vertical plates are provided between electron gun and screen to deflect the beam according to the input signal.

4. For what a triggering circuit is provided in a CRO?
In a CRO, a triggering circuit is provided for synchronising two types of deflections so that horizontal deflection starts at the same point of the input vertical signal each time it sweeps.

5.what is auadag?
Coating of a conducting material, known as aquadag, is provided over the interior surface of CRT in order to accelerate the electron beam after passing between the deflation plates and to collect electrons produced by the secondary emission when electron beam strikes the screen. 

6.what is meant by retrace time?
Retrace time is the time required by the electron beam to return to its original position on a CRT screen after being deflected to the right by a sawtooth waveform.

7.Explain what is Astigmatism control?
Astigmatism control is an adjustment that will provide sharp focus over the entire screen. 

8.Explain what is graticule?
Graticule is a scale on transparent material that is fitted to the face of CRT for the purpose of measurement.

9.Explain what are the essential components of a CRT?
The essential components of a CRT are electron gun, focussing and accelerating anodes, horizontal and vertical deflection plates, and evacuated glass envelope with phosphorescent screen. 

10.Explain what electron gun assembly is provided in CRT?
The sole function of an electron gun assembly in a CRO is to provide a narrow and sharply focused electron beam with is accelerated towards the phosphor screen.

Monday 11 September 2017


*Interview questions and answers*

1)semiconductor materials have________________temperature cofficient
Ans . negative

2)The Hall effect voltage in intrinsic silicon
Ans. is negative

3)The effect of doping intrinsic semiconductor is to
Ans. move the Fermi level away from the centre of the forbidden band

4)The function of the safety resistor in ohm meter is to
Ans. limit the current in the coil

5)Which transducer converts heat energy into electrical energy
Ans. thermocouple

6)In CRT the focusing anode is located
between pre accelerating and accelerating anodes

7)Aquadag is used in CRO to collect
Both primary and secondary electrons

8)A device that changes one form of energy to another is called.

9)The electric device which blocks DC but allows AC is called:

10)Which of the following electrical equipment cannot convert ac into dc

11)turn on and turn off times of transistor depends on
junction capacitances

12)the surface dark current of a photodetector depends on
surface defects.

13)a solar cell is a device which uses
photo voltaic effect.

14)GaAs led’s emit radiation in the
infrared region

15)the wavelength of emitted light in led depends on
energy gap of the material

16)the input Gate current of FET is of the order of

18)the drain source voltage at which drain current becomes constant is called
pinch off voltage

19)FET’S are basically
*Ans* voltage controlled devices.

 Microprocessor Interview Questions

Schmitt Trigger Interview Questions

Ultrasound Interview Questions

Embedded Systems Interview Questions

Motors Interview Questions

Basic Electrical Interview Questions

Basic Electrical Interview Questions 2

Top Electrical Interview Questions

Most Common Electronic Interview Questions

Electronic Circuits Interview Questions

Optical Electronic Interview Questions

Power Electronics Interview Questions

Instrumentation Interview Questions 2

Instrumentation Interview Questions 1

Instrument Transformer Interview Questions

Friday 8 September 2017



Interview questions and answers

The probability that a device will perform within its specifications for the number of

operations or time period specified.


The closeness of repeated samples under exact operating conditions.


The similarity of one measurement to another over time, where the operating

conditions have varied within the time span, but the input is restored.


The smallest interval that can be identified as a measurement varies.

The frequency of oscillation that is maintained due to the natural dynamics of the



Defines the behaviour over time of the output as a function of the input. The output

is the response or effect, with the input usually noted as the cause.

*Self Heating*

The internal heating caused within a device due to the electrical excitation. Self-

heating is primarily due to the current draw and not the voltage applied, and is

typically shown by the voltage drop as a result of power (I2

R) losses.


This defines how much the output changes, for a specified change in the input to the


Used in closed loop control, the setpoint is the ideal process variable. It is

represented in the units of the process variable and is used by the controller to

determine the output to the process.

*Span Adjustment*
The difference between the maximum and minimum range values. When provided

in an instrument, this changes the slope of the input-output curve.

*Steady state*

Used in closed loop control where the process no longer oscillates or changes and settles at some defined value.

Shortened form of static friction, and defined as resistance to motion. More

important is the force required (electrical or mechanical) to overcome such a


This is a measure of the force required to cause a deflection of an elastic object.

*Thermal shock*
An abrupt temperature change applied to an object or device.

*Time constant*

Typically a unit of measure which defines the response of a device or system. The

time constant of a first order system is defined as the time taken for the output to

reach 63.2% of the total change, when subjected to a step input change.

An element or device that converts information from one form (usually physical,

such as temperature or pressure) and converts it to another ( usually electrical, such

as volts or millivolts or resistance change). A transducer can be considered to

comprise a sensor at the front end (at the process) and a transmitter.


A sudden change in a variable which is neither a controlled response nor long


A device that converts from one form of energy to another. Usually from electrical

to electrical for the purpose of signal integrity for transmission over longer distances

and for suitability with control equipment.

Generally, this is some quantity of the system or process. The two main types of variables that exist in the system are the measured variable and the controlled

variable. The measured variable is the measured quantity and is also referred to as

the process variable as it measures process information. The controlled variable is

the controller output which controls the process.

This is the periodic motion (mechanical) or oscillation of an object.

*Zero adjustment*
The zero in an instrument is the output provided when no, or zero input is applied.

The zero adjustment produces a parallel shift in the input-output curve.

07)What do you mean by a voltage to frequency converter?

A device which convert an analog voltage into a pulse signal which frequency is proportional to the applied input voltage.

08)what is the function of frequency to voltage converter?*

A device which convert the frequency of the input signal into an proportional output voltage.

09)what are main application of frequency to voltage converter?*. 

The main applications of these are follows-

1. It is used to control the speed of motor.

2. It is used for rotational measurement.

3. It is used for digital to analog conversion.

10)Explain the Timer IC-555?*

IC-555 is timer IC which is used in a stable, multivibrator, square wave generator, triangular wave generator, pulse modulator and pulse detector circuit.

11)Explain the main feature of IC-723.

The main feature of IC-723 are-

1. Input voltage ( 9.5 Volt-40 volt)

2. Regulated output voltage (2 to 37 v)

3. Maximum load current = 150 ma.

4. Internal power dissipation is 800 mvolt.

12)what is function of pulse width modulator?*

In pulse width modulator the width of the output pulse is varying according to the variation in the amplitude of modulating signal

Thursday 7 September 2017

common electronics and electrical interview questions with answer

common electronics and electrical interview questions with answer
1.Explain what is a dc power supply?
The part of the equipment that converts ac into dc is called dc power supply.
2. Explain what is a rectifier?
A rectifier is a device which converts alternating current (or voltage) into unidirectional current (or voltage).
3. Explain what is PIV of a diode in a rectifier circuit?
Peak Inverse Voltage (PIV) is the maximum possible voltage that occurs across a diode when it is reverse biased.

4. Explain what is the importance of peak inverse voltage?
If the applied voltage in reverse biased condition exceeds peak inverse voltage (PIV) rating of the diode, then the diode may get damaged.
5. Explain why half-wave rectifiers are generally not used in dc power supply?
The type of supply available from half-wave rectifier is not satisfactory for general power supply. That is Explain why it is generally not used in dc power supply.
6. Explain why diodes are not operated in the breakdown region in rectifiers?
In breakdown region, a diode has a risk of getting damaged or burnt because the magnitude of current flowing through it increases in an uncontrollable manner. That is Explain why didoes are not operated in the breakdown region in rectifiers.
7. Define ripple as referred to in a rectifier circuit.
The ac component contained in the pulsating output of a rectifier is known as ripple.
8. Explain what is transformer utilization factor?
Transformer utilization factor is defined as the ratio of power delivered to the load and ac rating of secondary of supply power transformer.
9. The output of a 60Hz full-wave bridge rectifier has a 60 Hz ripple. It this circuit working properly?
A full-wave rectifier with 60Hz input must have lowest ripple frequency equal to twice the input frqeuency i.e. 120Hz. If the ripple frequency is 60Hz, it means some diodes in the circuit are not working.
10. Explain what is meant by filter?
Filter is a device that converts pulsating output of rectifier into a steady dc level.
11. Explain why series inductor and L-section filters cannot be used with half-wave rectifiers?
Series inductor and L-section filters cannot be used with half-wave rectifiers because operation of series inductor depends upon the current through it and needs a minimum current to flow at all times.
12. Explain why capacitor input filter is preferred to choke input filter?
In capacitor input filter, the dc output is much larger and ripples are less in comparison to those in choke input filter. So, capacitor input filter is preferred to choke input filter.
13. Explain why π-filters are not suitable for varying loads?
Voltage regulation in case of π-filters is very poor and, therefore, π-filters are not suitable for varying loads.
14. Explain why R-C filters are suitable only for light loads?
R-C filters have poor voltage regulation and need adequate ventilation to dissipate the heat developed in the resistor R. Thus R-C filters are suitable only for light loads.
15. Explain why is bleeder resistance employed in a filter circuit?
A resistance, called the bleeder resistance, is placed across the filter ouput, to provide flow of necessary minimum current through the choke at all time.
16. Explain what is the purpose of bleeder resistance in a rectifier circuit using L-C filter?
Bleeder resistance RB is placed in parallel with the load so as to maintain a certain minimum current through the choke, even the load resistor gets open-circuited, and improves filtering action.
17. Explain what is meant by voltage regulation of a dc power supply?
The change in voltage from no-load to full-load condition is known as voltage regulation.
18. Explain why is it necessary to include voltage stabilizer in a power supply?
The magnitude of output dc voltage may vary with the variation of either the input ac voltage or the magnitude of load current. So at the output of a rectifier-filter combination a voltage stabilizer is required.
19. Explain what are the commonly used filters?
The most commonly used filters are low-pass, high-pass band-pass, band-reject and all-pass filters.
20. Explain what is the difference between active and passive filters?
A passive filter is formed with passive components, such as resistors, inductors and capacitors while active filters make use of transistors or op-amps in addition to resistors and capacitors.
21. Explain why are active filters preferred
Active filters are preferred over passive filters because they provide gain and frequency adjustment flexibility. They pose no loading problem because of high input impedance and low output impedance and they are comparatively less expensive.
22. Explain what is a low-pass filter?
A filter that provides a constant output from dc upto a cutoff frequency fC and then passes no signal above that frequency is called a low-pass filter.
23. Explain what is a high-pass filter?
A filter that provides or passes signals above a cutoff frequency fCis called a high-pass filter. It has a zero gain starting from zero to a frequency fC and above this frequency the gain is constant.


Interview questions on ELECTRONICS
1. Define buck boost converter.
2. Explain the application of using buck boost converter.
3. Explain the different modes of buck boost converter
4. Define Flyback converter.
5. Explain the application of using Flyback converter.
6. Explain the different modes of Flyback converter
7. What is AM transceiver.
8. What is FM transceiver.
9. Applications of AM transceiver.
10. Applications of FM transceiver.
11. What is the purpose of using data modem.
12. Give application of wireless modem.
13. Mention the protocols used in data transfer.
14. What is PCB?
15. List the materials used for manufacturing PCB
16. Define Voltage regulator.
17. Explain the operating condition in SCR.
18. Differentiate between microcontroller and microprocessor.
19. State advantage in using microcontroller while designing any system.
20. Define Timer.
21. Define Various modes of operation of timer.
22. How a timer enhances for controlling any process.
23. Define Amplifier.
24. What is the purpose of using an instrumentation amplifier.
25. Define digital function generator?
26. What is DSP?
27. Define voltage controller?
28. State the difference between AC and DC voltage.
29. Define signal sampling
30. Define Nyquist criteria.



*Interview questions on Electronic circuits*      

what is stability factor?
what is transistor,transistor biasing?
what is thermal runaway?
what is dc load line?
what is stablization?
what is bypass capacitor?
what is the need of coupling capacitor?
what is the advantage of all amplifiers?
what is class A,B,AB,C,. amplifiers?
what is the advantage of above amplifiers?
what is transformer coupled amplifier? millers theorem?
define advantage of h parameters?
how to cascade a amplifier?
what is darlington pair?
what is swapping resistor?
what is cross over distortion?
figure of merit?
source follower?
list the application of source follower?
differential amplifier?
list the advantage of differential amplifier?
what is filter and its types?
ripple filter?
define gain stablity?
cut off frequency?
what is rectification and types?
what is rectifier?
what is half and full wave rectifier?
what is rectifier efficiency?
what is peak inverse voltage?
what are the different biasing circuits?


*Interview questions on OPTICAL*

  1. State Faraday’s rotation law. 
  2.  State the properties of S matrix. 
  3. What are the reasons that low frequency parameters cannot be Measured in 
  4. microwaves? 
  5. 4. State the two parameters that describe a directional coupler? Define them. 
  6. 5. State TEE junction theorems. 
  7. 6. What is S matrix and write the S matrix of N port network? 
  8. 7. What is meant by hybrid coupler? 
  9. 8. Compare z parameters and ABCD parameters with S-parameters. 
  10. 9. What are hybrid rings? 
  11. 10.List the parameters that determine the performance of a directional coupler. 
  12. 11. Explain the action of a rat-race junction. 
  13. 12.Why are waveguide bends and twists constructed so that the direction of 
  14. propagated energy is 
  15. gradually changed? 
  16. 1.Define GUNN effect. 
  17. 2. What is the necessary condition for an IMPATT to produce oscillations? 
  18. 3. List the differences between microwave transistor and TED devices. 
  19. 4. What are the advantages and disadvantages of parametric amplifier? 
  20. 5. What is meant by avalanche transit time device? 
  21. 6. Discuss the applications of PIN diode. 
  22. 7. What is a parametric amplifier? How is it different from a normal amplifier? 
  23. 8. What is the theory of a negative resistance amplifier? 
  24. 9. Explain how a tunnel diode can be used as a amplifier. 
  25. 10.List the several donation formation modes of a Gunn diode. 
  26. 11.State the performance characteristics of IMPATT and TRAPATT diode. 
  27. 12. An IMPATT diode has a drift length of 2 µm. Determine the operating 
  28. frequency of IMPATT diode if the drift velocity for Si is 107 cms/sec 
  29. 1. Draw the electronic admittance diagram of reflex klystron. 
  30. 2. State the differences between TWT and klystron? 
  31. 3. Can a two cavity klystron amplifier be used an oscillator? If yes, how? 
  32. 4. What is the purpose of slow wave structures in TWT? 
  33. 5. What is meant by frequency pushing and frequency pulling?. 
  34. 6. What is velocity modulation? 
  35. 7. What are the limitations of conventional tubes at microwave 
  36. frequencies?Explain how these 
  37. limitations can be overcome.
  38. 8. What are the performance characteristics of a Klystron amplifier? 
  39. 9. How is bunching achieved in a cavity magnetron? 
  40. 10. What are cross field deices? 
  41. 11. How is tuning achieved in reflex klystron oscillators? 
  42. 12. What is strapping in magnetron? How is the same effect obtained without 
  43. strapping? 
  44. 1. What are the advantages of microstrip line over strip line? 
  45. 2. What are the advantages of MMIC over discrete circuit? 
  46. 3. What are the properties of dielectric materials? 
  47. 4. What are the losses in strip lines? 
  48. 5. List the various MMIC fabrication techniques. 
  49. 6. Microstrip line is also called an open strip line.Comment on this. 
  50. 7. Why is it difficult to establish microstrip short circuits? 
  51. 8. What are the design considerations for a microstrip line? 
  52. 9. Why are propagating modes along the strip lines are non-TEM and not pure 
  53. TEM modes? 
  54. 10.How are waveguides different from normal two – wire transmission lines? 
  55. 11.Give the physical interpretation for phase and group velocity in relation to 
  56. speed of light. 
  57. 1. What is Bolometer? Give two examples? 
  58. 2. A wave guide load is used to absorb power of 2W., reflected power is 
  59. 3mW.Find magnitude of 
  60. VSWR. 
  61. 3. Why reflex klystron is a square wave 1kHz PAM while microwave 
  62. measurements are done using 
  63. VSWR? 
  64. 4. What are the sources of error in return loss measurement using a waveguide 
  65. reflectometer and 
  66. klystron source? 
  67. 5. What is meant by duty cycle? 
  68. 6. How are microwave measurements different from low frequency 
  69. measurements? 
  70. 7. List the various techniques of measuring unknown frequency of a microwave 
  71. generator. 
  72. 8. How can you extend the range of power measurement? 
  73. 9. Describe how an ordinary voltmeter can be calibrated to VSWR directly.What 
  74. are the drawbacks 
  75. of such a VSWR meter? 
  76. 10. List any two methods of measuring impedance of a terminating load in a 
  77. microwave system. 
  78. 11. Explain the concept of double minimum method of measuring VSWR.
  79. 1. Among Microwaves and light waves which have high bit rate distance 
  80. product?Why? 
  81. 2. Mention the three advantages of optical fiber as waveguide over conventional 
  82. metallic waveguide? 
  83. 3. What is meant by mode and index profile? 
  84. 4. Mention the advantages of Graded Index fiber. 
  85. 5. Write the expression for the refractive index in Graded index fiber. 
  86. 6. Define Numerical Aperture of step index fiber. 
  87. 7. Give the expression of the effective number of modes that are guided by a 
  88. curved 
  89. multimode fiber of radius ‘ a’. 
  90. 8. State Snells Law. 
  91. 9. Define Critical angle? 
  92. 10. Define TIR? 
  93. 11. What is the need of Cladding? 
  94. 12. Define core index difference. 
  95. 13. Define refractive index? 
  96. 14. What are leaky modes in optical fibers? 
  97. 15. Define External reflection of light rays? 
  98. 16. What is meant by modes of waveguide? 
  99. 17. Define V number? 
  100. 18. What is relation between V number and power flow in cladding? 
  101. 19. What is the fundamental parameter of SM fiber? 
  102. 20. Give the relation between rays and modes? 
  103. 21. What are the advantages and disadvantages of SM fiber? 
  104. 22. What are the advantages and disadvantages of MM fiber? 
  105. 23. Define skew rays and merdional rays? 
  106. 24. Define cutoff conditions? 
  107. 25. What is meant by Degenerate modes? 
  108. 26. What is meant by linearly polarized modes? 
  109. 27. Define MFD? 
  110. 28. Define Bi refrigence and beat length? 
  111. 29. A point source of light is 12cm below the surface of a large body of water 
  112. (n=1.33). 
  113. What is the radius of the largest circle on the water surface through which the 
  114. lights 
  115. can emerge? 
  116. 30. Consider a parabolic index waveguide with n1=1.75,n2=1.677 and core radius 
  117. 52µm. 
  118. Calculate the numerical aperture at the axis and at a point 20µm from the axis. 
  119. 31. Why do we prefer step index single mode fiber for long distance 
  120. communication? 
  121. 32. Why do we use LP01 mode for long distance communications? 
  122. 33. What are three operating windows? 
  123. 34. Alight ray is incident from glass to air. Calculate critical angle?
  124. 1. An optical signal has lost 55% of its power after traversing 3.5 km of fiber. 
  125. What is 
  126. the loss in dB/km of this fiber? 
  127. 2. Define mode-field diameter. 
  128. 3. What are the causes of absorption? 
  129. 4. Define normalized propagation constant. 
  130. 5. List the basic attenuation mechanisms in an optical fiber. 
  131. 6. What is meant be mode coupling ? What causes it ? 
  132. 7. Mention the two causes of intramodal dispersion. 
  133. 8. Define fiber loss. 
  134. 9. What do you mean be polarization mode dispersion? 
  135. 10. Commonly available single mode fibers have beat lengths in the range 10cm 
  136. <Lp 
  137. <2m. What range of refractive index differences does this correspond to? 
  138. 11. Find the coupling loss for two fibers having core refractive index profiles _E 
  139. =2.0 and _R =1.5 
  140. 12. Define Raleigh Scattering loss. 
  141. 13. Define Mie Scattering loss. 
  142. 14. When the mean optical power launched into an 8 km length of fiber is 120 µw. 
  143. Determine the overall signal attenuation or loss in decibels. 
  144. 15. How are micro bending losses reduced? 
  145. 16. Distinguish intrinsic and extrinsic absorption. 
  146. 17. Distinguish dispersion shifted and dispersion flattened fibers. 
  147. 1. Define radiance. 
  148. 2. What is meant by “ population inversion”? 
  149. 3. what is meant by heterojunction? 
  150. 4. What is meant by indirect band gap semiconductor material? 
  151. 5. Draw the three key transition processes involved in laser action. 
  152. 6. Give examples for direct and indirect semiconductor materials. 
  153. 7. Define internal quantum efficiency of an LED. 
  154. 8. Name few splicing methods in fiber optics. 
  155. 9. Compare LED and LASER. 
  156. 10. What so you mean by heterojunction ? Mention its advantages. 
  157. a. List the different types of mechanical misalignments that can occur between 
  158. two joined fibers. 
  159. b. Calculate the ratio of stimulated emission rata to the spontaneous emission 
  160. rate for a lamp operating at a temperature of 1000 K. Assume average 
  161. operating wavelength is 0.5µm. 
  162. 11. Define lambertian pattern . 
  163. 12. Define FWHM. 
  164. 13. Define Modal or speckle noise. 
  165. 14. Define “ Kinks”. 
  166. 15. Define Mode partition noise.
  167. 16. Define Lensing Schemes. 
  168. 17. Define Splicing ? What are types of Splicing.? 
  169. 18. What are the Characteristics of Light Source . 
  170. 1. Define diffusion length. 
  171. 2. Define avalanche effect . 
  172. 3. Define responsivity. 
  173. 4. Define Quantum efficiency of photo detector. 
  174. 5. Write the noise sources in the receiver section. 
  175. 6.Define Quantum limit. 
  176. 7.What are the desired features of photo detector. 
  177. 8.A photo diode is constructed of GaAs which has a bandgap energy of 1.43Ev 
  178. at 300k. 
  179. What is meant by long wavelength cutoff? 
  180. 9.What are the benefits of trans impedance amplifier. 
  181. 10.Define long wave length cutoff related photo diode. 
  182. 11.What is meant by bulk dark current? 
  183. 12.A photo diode has a capacitance of 6pf.Calculate the max load resistance 
  184. which allows 
  185. an 8MHz post defection BW. 
  186. 13. What is meant by impact ionization. In APD? 
  187. 14.What is transit time of photo carriers? 
  188. 15.What is meant by ionization rate? 
  189. 16. Define avalanche multiplication? 
  190. 17.Define S/N ratio of an optical receiver?What are the conditions are required 
  191. to achieve high S/N? 
  192. 18.Define BER? 
  193. 19.Define Extinction ratio? 
  194. 20. Define photo current? 
  195. 21. What is p+ _pn+ reach through structure? 
  196. 22.Define excess noise factor? 
  197. 23. What is meant by Pre amplifier? What are the advantages of pre amplifier? 
  198. 24.Whar are the draw backs of high impedance amplifier? 
  199. 1. List out the requirements that are to be considered in analyzing a link 
  200. 2. Differentiate link power budget and rise time budget. 
  201. 3. What is SONET? How does it differ from SDH? 
  202. 4. What are solitons? 
  203. 5. What is meant by ‘modal noise’?



Q.1 What do you mean by Logic Gates?
Q.2 What are the applications of Logic Gates?
Q.3 What is Truth Table?
Q.4 Why we use basic logic gates?
Q.5 Write down the truth table of all logic gates?
Q.6 What do you mean by universal gate?
Q.7 Write truth table for 2 I/P OR, NOR, AND and NAND gate?
Q.8 Implement all logic gate by using Universal gate?
Q.9 Why is they called Universal Gates?
Q.10 Give the name of universal gate?

Q.1 Draw circuit diagram of Half Adder circuit?
Q.2 Draw circuit diagram of Full Adder circuit?
Q.3 Draw Full Adder circuit by using Half Adder circuit and minimum no. of logic
Q.4 Write Boolean function for half adder? Q.5 Write Boolean function for Full
Q.6 Design the half Adder & Full Adder using NAND-NAND Logic.

Q.1 Draw circuit diagram of Half Subtractor circuit?
Q.2 Draw circuit diagram of Full Subtractor circuit?
Q.3 Draw Full Subtractor circuit by using Half Subtractor circuit and minimum
no. of logic gate?
Q.4 Write Boolean function for half Subtractor?
Q.5 Write Boolean function for Full Subtractor?

Q.1 What is Excess-3 code? Why it is called Excess-3 code?
Q.2 What is the application of Excess-3 Code?
Q.3 What is ASCII code?
Q.4 Excess-3 code is Weighted or Unweighted?
Q.5 Out of the possible 16 code combination? How many numbers used in Excess-3

Q.1. What is Demorgan’s Law?
Q.2. Show the truth table for Demorgan’s Theorem?
Q.3.What is Minterm & Maxterm?
Q.4. How Minterm can be converted in Max term?
Q.5. What is Hybrid function?

Q.1 What is Flip-Flop?
Q.2 What is Latch circuit?
Q.3 Draw a truth –tables of S-R, J-K, D and T?
Q.4 What is the disadvantages of S-R Flip-Flop?
Q.5 How can you remove the problem of S-R Flip –Flop?
Q.6 Make circuit diagram of S-R, J-K, D and T Flip-Flop?
Q.7 What do you understand by Race Aground condition? How it is over come
in J-K Flip Flop?

Q.1 Explain the principle of Multiplexer?
Q.2 Draw a circuit diagram of 4: 1 Multiplexer?
Q.3 What are the advantages of Multiplexer?
Q.4 What are the disadvantages of Multiplexer?
Q.5 Make the Truth-table of Multiplexer?

Q.1 Explain about Demultiplexer?
Q.2 Draw a circuit diagram of 1: 4 Demultiplexer?
Q.3 Make a logic diagram of 1: 4 Demultiplexer?
Q.4 What is the application of Demultiplexer?
Q.5 What is the difference between Multiplexer and Demultiplexer?

Q.1 Give some application of 555 timers IC?
Q.2 What are the basic elements of a 555 timer IC?
Q.3 Give important features of 555 timer IC?
Q.4 What do you mean by the term duty cycle of an astable multivibrator?
Q.5 For monostable operation of 555 timer IC, what mature of input trigger pulse
is needed

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