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Basic Electronics Expected Questions for Industrial Extension officer, RRB ,SSC

Sikha January 22, 2019

INDUSTRIAL EXTENSION Officer Exam coaching
EEEMADE EASY

•Application of DC voltage to a diode, transistor, or other device to produce a desired mode of operation is called
•biasing....
•reduction
•bounding
•modulation

Group of eight bits in a binary data is called
•nibble....
•bitwidth
•byte
•word

Transistor in which both free electrons and holes are current carriers is termed as
•bipolar transistor....
•dipolar transistor
•tripolar transistor
•semipolartransistor

Amount of energy required to produce full conduction across pnjunction in forward bias is called
•barrier potential....
•barrier difference
•barrier intensity
•barrier density

Region of semiconductor which is very thin and lightly doped as compared to other regions is called
•emitter
•collector
•source
•base...

•Process of imparting impurities to an intrinsic semiconductor materials in order to control its conduction characteristics is called
•doping....
•modulation
•differentiation
•integration

LED stands for
•Light Emitting Damp
•Light Emitting Diode......
•Light Emitter Diode
•Long Emitter Diode

•A symbolic diagram representing an electrical or electronic circuit is termed as
•symbolic diagram
•flowchart
•schematic diagram....
•block diagram
•A curve which represents relationship of diode voltage and current is
•VI laplacecurve
•VI characteristic.....
•VI Coupled curve
•VI dominant curve

•Angle which defines whether a light ray will be reflected or refracted when it strikes surface is called
•angle of modulation
•angle of incident
•critical angle.....
•angle of reluctance

•Most numerous charge carrier in a doped semiconductor material is called
•majority carriers....
•minority carriers
•holes
•electrons

•Embedded systems is branch of
•electrical
•electro-mechanical
•electronics....
•telecommunication

•Two transistors; one npnand other pnphaving matched characteristics are termed as
•Captured Symmetry transistors
•Computer Symmetry transistors
•Complementary System transistors
•Complementary Symmetry transistors....

•Resistance of resistor is measured in
•Ohm....
•Farads
•Volts
•Ampere

•Uncharged particle found in nucleus of an atom is
•electron
•proton
•neutron....
•photon

•LASCR stands for
•Light Activated System Controlled Rectifier
•Light Activated Silicon Controlled Rectifier....
•Light Activated System Common Rectifier
•Light Advanced System Controlled Rectifier

•Most heavily doped of three semiconductor regions of a BJT is called
•collector
•base
•emitter.....
•drain

•Removal or addition of an electron from or to a neutral atom so that resulting atom has a net positive or negative charge is called
•determination
•differentiation
•integration
•ionization....

•Application of DC voltage to a diode, transistor, or other device to produce a desired mode of operation is called
•biasing....
•reduction
•bounding
•modulation

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Basic Electronics Expected Questions for Industrial Extension officer, RRB ,SSC

Reviewed by Sikha on January 22, 2019 Rating: 5

Industrial Extension Officer coaching Basic Electronics Semiconductor

Sikha December 19, 2018

EEE made easy
Visit "notebukofaprofessor.blogspot.in" for study materials, note of this video

Q .A semiconductor has ………… temperature coefficient of resistance.

Positive
Zero
Negative.....
None of the above

Q A semiconductor is formed by ……… bonds.

Covalent.....
Electrovalent
Co-ordinate
None of the above

Q.The most commonly used semiconductor is ………..

Germanium
Silicon....
Carbon
Sulphur

Q. A semiconductor has generally ……………… valence electrons.

2
3
6
4....

Q. The resistivity of pure germanium under standard conditions is about ……….

6 x 104Ω cm
60Ω cm....
3 x 106Ω cm
6 x 10-4Ω cm

Q.The resistivity of a pure silicon is about ……………

100 Ω cm
6000 Ω cm.....
3 x 105 Ω m
6 x 10-8 Ω cm

Q. When a pure semiconductor is heated, its resistance …………..

Goes up
Goes down....
Remains the same
Can’t say

Q.When a pentavalent impurity is added to a pure semiconductor, it becomes ………

An insulator
An intrinsic semiconductor
p-type semiconductor
n-type semiconductor.....

Q. Addition of pentavalent impurity to a semiconductor creates many ……..

Free electrons....
Holes
Valence electrons
Bound electrons

Q. A pentavalent impurity has ………. Valence electrons

3
5....
4
6

Q. An n-type semiconductor is ………

Positively charged
Negatively charged
Electrically neutral...
None of the above

Q. A trivalent impurity has ….. valence electrons

4
5
6
3.....

Q. Addition of trivalent impurity to a semiconductor creates many ……..

Holes...
Free electrons
Valence electrons
Bound electrons

Q. A hole in a semiconductor is defined as …………….

A free electron
The incomplete part of an electron pair bond..
A free proton
A free neutron

Q. The impurity level in an extrinsic semiconductor is about ….. of pure semiconductor.

10 atoms for 108 atoms
1 atom for 108 atoms....
1 atom for 104 atoms
1 atom for 100 atoms

Q. As the doping to a pure semiconductor increases, the bulk resistance of the semiconductor ………..

Remains the same
Increases
Decreases....
None of the above

Q.A hole and electron in close proximity would tend to ……….

Repel each other
Attract each other....
Have no effect on each other
None of the above

Q. In a semiconductor, current conduction is due to ……..

Only holes
Only free electrons
Holes and free electrons....
None of the above

Q. The random motion of holes and free electrons due to thermal agitation is called ……….

Diffusion....
Pressure
Ionisation
None of the above

Q. At room temperature, an intrinsic silicon crystal acts approximately as ……

A battery
A conductor
An insulator....
A piece of copper wire
Q. A forward biased pn junction diode has a resistance of the order of

Ω...
kΩ
MΩ
None of the above

Q. The battery connections required to forward bias a pn junction are ……

+ve terminal to p and –ve terminal to n...
-ve terminal to p and +ve terminal to n
-ve terminal to p and –ve terminal to n
None of the above

Q. The barrier voltage at a pn junction for germanium is about ………

5 V
3 V
Zero
0.3 V.....

Q. In the depletion region of a pn junction, there is a shortage of ……..

Acceptor ions
Holes and electrons....
Donor ions
None of the above

Q.A reverse bias pn junction has …………

Very narrow depletion layer
Almost no current....
Very low resistance
Large current flow

Q.A pn junction acts as a ……….

Controlled switch
Bidirectional switch
Unidirectional switch....
None of the above

Q. A reverse biased pn junction has resistance of the order of

Ω
kΩ
MΩ....
None of the above

Q. The leakage current across a pn junction is due to …………..

Minority carriers....
Majority carriers
Junction capacitance
None of the above

Q.When the temperature of an extrinsic semiconductor is increased, the pronounced effect is on……

Junction capacitance
Minority carriers....
Majority carriers
None of the above

Q. With forward bias to a pn junction , the width of depletion layer ………

Decreases....
Increases
Remains the same
None of the above

Q. The leakage current in a pn junction is of the order of

Aa
mA
kA
µA....

Q. In an intrinsic semiconductor, the number of free electrons ………

Equals the number of holes....
Is greater than the number of holes
Is less than the number of holes
None of the above

Q. At room temperature, an intrinsic semiconductor has ……….

Many holes only
A few free electrons and holes....
Many free electrons only
No holes or free electrons

Q. At absolute temperature, an intrinsic semiconductor has ……….

A few free electrons
Many holes
Many free electrons
No holes or free electrons....

QThe strength of a semiconductor crystal comes from ……..

Forces between nuclei
Forces between protons
Electron-pair bonds.....
None of the above

Industrial Extension Officer coaching Basic Electronics Semiconductor

Reviewed by Sikha on December 19, 2018 Rating: 5

Cyclotron

Sikha August 13, 2017

Cyclotron

Cyclotron is a machine to accelerate charged particles or ions to high energies. It was invented by E.O Lawrence and M.S Livingston.

Cyclotron uses both electric and magnetic fields in combination to increase the energy of charged particles.
The electric and magnetic fields are perpendicular to each other ( and called as crossed fields)
Principle:- the frequency of revolution of the charged particle in a magnetic field is independent of its energy.

Working:

o The particles move most of the time inside two semi circular disc –like metal containers, D₁ and D₂ , which are called ‘dees’ ( as they look like the letter ‘D’)

o Inside the metal boxes, the particle is shielded and is not acted on by the electric field.

o The magnetic field acts on the particle and makes it go round in a circular path inside the dee.

o Every time the particle moves from one dee to another, it is acted upon by the electric field.

o The sign of the electric field is changed alternately in tune with the circular motion of the particle.

o Thus, the particle is always accelerated by the electric field

o Each time, the acceleration increases the energy of the particle.

o As energy increases, the radius of the circular path also increases. So, the path is a spiral one.

o The whole assembly is evacuated to minimize collisions between the ions and the air molecules.

o A high frequency a.c voltage is applied to the dees.

In the fig, positive ions or positively charged particles (protons) are released at the centre P. They move in a semi-circular path in one of the dees and arrive in the gap between the dees in a time interval T/2.

T- period of revolution.

T=1/f_C = 2πm/qB

Or , f_C = qB/2 πm

f_C – Cyclotron frequency

f_a – frequency of applied voltage

At resonance, f_C= f_a

The phase of the supply is adjusted so that when the positive ions arrive at the edge of D_1, the dee D₂ is at a lower potential and the ions are accelerated across the gap.
Inside the dees, the particles travel in a region free of the electric field.
The increase in their K.E = qV each time they cross from one dee to another.
(V= the voltage across the dees at that time)
Thus, radius of the path increases each time they cross the dees.
The ions are repeatedly accelerated across the dees until they have the required energy to have a radius approximately equal to that of the dees.
They are then deflected by a magnetic field and leave the system via an exit slip.

From

Applications

Used to bombard nuclei with energetic particles to accelerate nuclei and study the resulting nuclear reactions
Used to implant ions in to solids and modify their properties. Or to synthesize new materials.
Used in hospitals to produce radio active substances that can be used in diagnosis and treatment.

Cyclotron

Reviewed by Sikha on August 13, 2017 Rating: 5

Syllabus for Lecturer in polytechnics -EEE

Sikha November 04, 2016

Technical Mathematics

I. Matrices – Identification of Matrices, matrix operations, adjoint and inverse.

II. Determinants – Evaluation of second and third order, minors and cofactors,

solutions of simultaneous linear equation in three unknown using Cramer’s

rule.

III. Binomial Series – Expansions using Binomial theorem.

IV. Trigonometric functions – Signs of functions in each quadrant. Trigonometric

values of angles, properties of trigonometric functions, applications of the

identities sin (A ± B), cos (A ± B) and tan (A ± B).

V. Coordinate geometry – Equations to a straight line – slope-intercept form,

intercept form, Angle between two lines, condition for two lines to be

perpendicular, parallel.

VI. Differentiation – Limits and continuity, derivatives of functions, equation to

tangents and normals. Maxima and minima of functions of one variable.

VII. Integration of functions – Integration of different types of functions.

VIII. Applications of integration – Area bounded by a curve and X or Y axis,

solutions of differential equations using the method of variable separable,

solutions of linear differential equations of first order.

Basic Civil Engineering

Materials: Brick – varieties and strength, characteristics of good brick. Cement –

varieties and grade of cement and its uses. Steel – types of steel for reinforcement

bars, steel structural sections. Aggregates – types & requirements of good aggregates.

Concrete – grades of concrete as per IS code, water cement ratio. Workability,

mixing, batching, compaction and curing.

Construction: Parts of building – foundation – types of foundations – spread

footing, isolated footing, combined footing, Raft, pile and well foundations. Masonry

– types rubble masonry, brick masonry, English bond and Flemish bond. (One brick

wall).

Surveying: Chain surveying – principles, instruments, ranging, and chaining survey

lines, field work and field book, selection of survey stations, units of land area.

Levelling: Levelling instruments, different types, bench mark, reduced level of

points, booking of field notes, reduction of levels by height of collimation method

(simple problem). Modern survey – instruments – Total station, Electronics

theodolite, Distomat.

Basic Mechanical Engineering

The importance of IC Engines: Definition, classification – two stroke engines,

four stroke engines, working of two stroke engines and four stroke engines with the

help of line sketches, comparison between two stroke and four stroke engines,

comparison between petrol and diesel engines, function of fly wheel, clutch, gearbox,

propeller shaft and differential in power transmission, explain with sketch the working

of differential, briefly explain power transmission of 4 wheel vehicle with line

diagram.

The importance of Power Plants: Introduction, classification of power plants –

working of hydroelectric power plant with schematic sketches – working of thermal

(Steam and Diesel) power plant with schematic sketches – working of nuclear power

plant with schematic sketches.

Basic Electrical Engineering

Review with discussion of electric current, potential difference, power, EMF,

resistance and its laws, Ohms law and series parallel circuit, electromagnetism,

generation of AC and DC supply.

Idea of Basic electrical circuit: Electrical supply and load and its functioning,

division of voltage and current in a parallel and series circuit – simple problems, units

of power and energy, solution of DC circuit with calculation of energy consumption

in an installation.

Circuit parameters: Resistance, Capacitance and inductance. AC circuit with R, L,

C. Simple solution of typical AC circuit with resistance, impedance, power and power

factor.

Electrical circuit of an installation: Earthing, lightning protection.

Essentials of Electronics Engineering

Active and passive devices – review only. LED – working, applications, comparison

of LED lighting and CFL lighting. Full wave rectifier – diagram and explanation, 5 V

power supply – with bridge rectifier and 7805. SMPS – block diagram and

advantages. Integrated circuits. SMDs – advantages. Static electricity – precautions in

handling electronic circuits.

Switches: ON / OFF, push to ON, push to OFF, push to ON / OFF, SPST, SPDT,

DPDT. Working and application of limit switches, proximity switches, relays.

Microcontrollers: Simple block diagram of 8 bit microcontrollers – application.

Mobile technology: CDMA and GSM. Compare – 2G and 3G technologies.

Inverter & UPS: Block diagram. Compare – inverter and UPS. Online and off line

UPS – differentiate. Battery selection for UPS and inverter.

E-waste: Health hazards of e-waste.

ELECTRICAL AND ELECTRONICS ENGINEERING

Module I : Electronic Circuits and Field Theory

Node and Mesh analysis, transient response of dc and ac networks, sinusoidal steady

state analysis, resonance, two port network, independent and dependent voltage and

current sources, coupled circuits, tuned coupled circuits, Network theorems –

superposition, reciprocity, substitution, compensation, Thevenin, Norton, Millman,

Telligen and Maximum power transfer theorems. Analysis of Three phase circuits,

symmetrical components, graph theory – analysis of network using cut-set and tri-set.

Filters constant – K low pass, high pass and band-pass filters – m derived, low pass,

high pass and band pass filters.

Gauss’s law and applications, electric field, electric potential, electric field lines,

electric dipoles, potential gradient, conductors, dielectrics, capacitance, polarisation,

method of images, dielectric strength, Biot-Savart’s law, Ampere’s circuital law,

Stoke’s theorem, scalar and vector magnetic potential, force between current carrying

wires, Maxwell’s equation – wave equation – Poynting theorem.

Module II : Electrical Machines

Single phase Transformer – leakage reactance, equivalent circuit, losses and

efficiency, voltage regulation, OC, SC and Sumpner’s tests, Distribution transformer,

all day efficiency, autotransformer – saving of copper three phase transformer –

connections, vector groupings, parallel operation.

DC machines – Types of excitation, constructional features.

DC generator – Emf equation, armature reaction & commutation, characteristics,

voltage build up, applications.

DC motor – Torque equation, characteristics of shunt, series & compound motors,

necessity & types of starters, speed control, applications, Swinburne’s test,

Hopkinson’s test.

Synchronous machines: - constructional features, winding factor.

Alternator: Types, synchronous reactance, voltage regulation, emf and mmf methods,

short circuit ratio, Two reaction theory, alternator on infinite bus, power angle

characteristics, parallel operation, effect of variation of power input & excitation.

Synchronous motor – principle of operation, methods of starting, hunting & its

reduction.

Three phase induction motor – constructional features, types, slip rotor frequency,

power flow, Torque – slip curve, effect of rotor resistance, starting methods, speed

control.

Single phase induction motor – double field revolving theory, starting methods.

Basic concepts of ac and dc drives.

Module III : Power Systems

Conventional and non-conventional systems of power generation, power plant

economics, load factor, demand factor, diversity factor, Transmission line parameters

– T and Π models GMD and GMR, ABCD constants, overload lines – arrangement of

conductors – sag, economic span, choice of transmission voltage, types of insulators, string

efficiency, distribution systems – types, comparison of DC and AC single phase and 3 phase

systems.

One line diagrams per unit quantities, formation of Y bus and Z Bus. Load flow studies –

Gauss – Seidal, Newton Raphson and Fast decoupled load flow methods.

Faults on power systems – LG, LL, LLG and 3 phase faults. Fault analysis using Z Bus.

Power system stability, steady state transient and dynamic stability, equal area criterion,

swing curve.

Protective relays: types and operation, protective zones, different protection schemes.

Circuit Breakers – types and operations, selection of circuit breakers, calculation of fault

KVA, protection against lightning and overvoltages.

Electric traction – speed – time curves - mechanics

Electric heating – Advantages, types and applications.

Principles of PMMC, moving iron, and electrodynamometer type instruments, error analysis,

measurement of voltage, current, power energy and power factor, induction type watt-hour

meter, DC bridges and AC bridges, magnetic measurements, Instrument transformers, digital

voltmeters and multimeters, digital measurements of frequency, phase angle, time interval.

Electronic energy meter, high voltage measurements, oscilloscopes, Data acquisition systems,

Transducers for temperature, flow and pressure.

Module IV : Control Systems

Open loop and closed loop system: Transfer function, force-voltage & force-current

analogy, block diagrams, signal flow graphs – Mason’s gain formula – characteristic

equation, time domain analysis – transient & steady state responses – time domain

specifications & steady state error.

Concept of stability – Routh’s stability criterion – Root locus – effect of addition of

poles and zeros.

Frequency domain analysis – Nyquist & Bode plots, gain margins and phase margin,

lag, lead and lag-lead compensators and their design using Bode plot.

State space analysis of system: State space models, state transition matrix, relationship

between state equations and transfer function, controllability and observability.

Nonlinear system: - characteristics, types of non-linearities, describing functions

analysis – concept, singular points – focus, centre, node and saddle points – limit

cycle.

Types of signals and systems, sampling process, sampling theorem, convolution of

discrete time signals, analysis of LTI systems using Z transforms. DFT and FFT,

Types of digital filters.

Module V : Electronics

BJT and FET amplifiers – biasing circuits, types of amplifiers, low frequency and

high frequency considerations. Oscillators and feedback amplifiers, operational

amplifier circuits and applications – simple active filters. VCO’s and timers. Voltage

regulators using linear IC’s, combinational and sequential logic circuits – flip flops,

counters, shift registers, TTL & CMOS logic families, memories – ROM, PROM,

EPROM & RAM.

Schmitt trigger, multivibrators, sample and hold circuits, A to D and D to A

converters, 8 bit and 16 bit microprocessor basics, architecture, programming and

interfacing.

Thyristors, triacs, GTO’s MOSFETS & IGBTS – principles of operation, triggering circuits, phase control

rectifiers, bridge converters – fully controlled and half controlled, Inverters and choppers.

NOTE: - It may be noted that apart from the topics detailed above, questions from other topics prescribed for the educational qualification of the post may also appear in the question paper. There is no undertaking that all the topics above may be covered in the question paper.

Syllabus for Lecturer in polytechnics -EEE

Reviewed by Sikha on November 04, 2016 Rating: 5

Lecturer in polytechnics- Electrical and Electronics Engineering

Sikha November 04, 2016

Kerala PSC has announced Lecturer in polytechnics Exam to be on 9,December 2016. This is a great opportunity for the B.Tech (EEE) aspirants. Here is the features of this job opportunity.

Department : Technical Education

Name of Post : Lecturer in Electrical & Electronics Engineering

(Govt. Polytechnics)

Scale of pay : ` 15600-39100/- (AICTE Pay band with AGP 5400)

Number of vacancies : 29 (Twenty Nine)

Method of appointment: Direct Recruitment

Age Limit: 20 -39 as on 01.01.2016

Qualifications

First Class Bachelor’s Degree in the appropriate branch of Engineering/Technology from a

Recognized University after undergoing a regular course of study

Note : Basic qualification for the post in the order of preference

(i) B.Tech/BE Degree in Electrical Engineering

(ii) B.Tech/BE Degree in Electical and Electronics

Last date of receipt of Applications: 08.2016 Wednesday up to 12.00 midnight.

The attractions of this job are in plenty. This examination provides you an opportunity unlike other ordinary PSC examinations as no other PSC exam will help you to get AICTE faculty benefits. A stress free working environment with lesser working hours compared to other jobs, around 2 month’s paid vacation in a year.

You can check the official notification Here

The Syllabus of Lecturer in Poytechnics Electrical and Electronics Engineering, is

Technical Mathematics
Basic Civil Engineering
Basic Mechanical Engineering
Basic Electrical Engineering
Essentials of Electronics
Electrical and Electronics Engineering

the detailed syllabus can be downloaded from here.

Lecturer in polytechnics- Electrical and Electronics Engineering

Reviewed by Sikha on November 04, 2016 Rating: 5

How do an induction cooker work?

Sikha June 19, 2016

An induction cooktop is simply an electromagnet you can cook with. Inside the glass cooktop, there's an electronically controlled coil of metal. When you turn on the power, you make a current flow through the coil and it produces a magnetic field all around it and (most importantly) directly above it. it generates a constantly changing magnetic field. It does not generate heat directly. You can put your hand on top of it and you won't feel a thing. (Warning: Don't ever put your hand on a cooktop that has recently been used for cooking because it may have become dangerously hot from the cooking pan that's been standing on top of it.)

Image result for how induction cooker works

Image result for how induction cooker works

When you stand a suitable cooking pan on top of an induction cooktop that's powered up, the magnetic field produced by the cooktop penetrates the metal of the pan. So we have a fluctuating magnetic field moving around inside a piece of metal (the base and sides of the pan)—and that makes an electric current flow through the pan too (that's all that induction means). Now this is not quite the same as the electric current that flows through a wire, carrying electrical energy in a straight line from (say) a battery to a flashlight bulb. It's a kind of whirling, swirling electric current with lots of energy but nowhere to go; we call it an eddy current. As it swirls around inside the metal's crystalline structure, it dissipates its energy. So the metal pan gets hot and heats up whatever food is inside it, first by conduction (it passes its heat energy directly to the food) but also by convection (liquid food rises and falls in the pan carrying heat with it).

How do an induction cooker work?

Reviewed by Sikha on June 19, 2016 Rating: 5

Power measurement in a transmission line

Sikha June 19, 2016

In a transmission line, power is measured by means of a voltmeter between the conductors,and an ammeter in series with one of the conductors (Fig.). Then the power, P (in watts) is equal to the product of the voltage E (in volts) and the current I(in amperes). This technique can be used in any transmission line, be it for 60-Hz utility service, or in a radio transmitting station. But is this indication of power the same as the power actually dissipated by the load at the end of the line? Not necessarily.

Recall, from the discussion of impedance, that any transmission line has a characteristic impedance. This value, Zo, depends on the size of the line conductors, the spacing between the conductors, and the type of dielectric material that separates the conductors. For a coaxial cable, Zo can be anywhere from about 50 to 150 Ω. For a parallel-wire line, it can range from about 75 Ω to 600 Ω.If the load is a pure resistance R containing no reactance, and if R _ Zo, then thepower indicated by the voltmeter/ammeter scheme will be the same as the true power

dissipated by the load. The voltmeter and ammeter must be placed at the load end of the transmission line.

If the load is a pure resistance R, and R < Zo or R > Zo, then the voltmeter and ammeter will not give an indication of the true power. Also, if there is any reactance in the load, the voltmeter/ammeter method will not be accurate.

The physics of this is rather sophisticated, and a thorough treatment of it is beyond

the scope of this course. But you should remember that it is always desirable to have the load impedance be a pure resistance, a complex value of R _ j0, where R _ Zo. Small discrepancies, in the form of a slightly larger or smaller resistance, or a small reactance, can sometimes be tolerated. But in very-high-frequency (VHF), ultra-high-frequency (UHF) and microwave radio transmitting systems, even a small impedance mismatch between the load and the line can cause excessive power losses in the line.

An impedance mismatch can usually be corrected by means of matching transformersand/or reactances that cancel out any load reactance.