Abbreviation and its meaning - Interesting

1.) GOOGLE : Global Organization Of Oriented Group Language Of Earth .

2.) YAHOO : Yet Another Hierarchical Officious Oracle .

3.) WINDOW : Wide Interactive Network Development for Office work
Solution

4.) COMPUTER : Common Oriented Machine Particularly United and used under Technical and Educational Research.

5.) VIRUS : Vital Information Resources Under Siege .

6.) UMTS : Universal Mobile Telecommunications System .

7.) AMOLED: Active-matrix organic light-emitting diode

8.) OLED : Organic light-emitting diode

9.) IMEI: International Mobile Equipment Identity .

10.) ESN: Electronic Serial Number .

11.) UPS: uninterruptible power supply .

12). HDMI: High-Definition Multimedia Interface

13.) VPN: virtual private network

14.) APN: Access Point Name

15.) SIM: Subscriber Identity Module

16.) LED: Light emitting diode.

17.) DLNA: Digital Living Network Alliance

18.) RAM: Random access memory.

19.) ROM: Read only memory.

20) VGA: Video Graphics Array

21) QVGA: Quarter Video Graphics Array

22) WVGA: Wide video graphics array.

23) WXGA: Widescreen Extended Graphics Array

24) USB: Universal serial Bus

25) WLAN: Wireless Local Area Network

26.) PPI: Pixels Per Inch

27.) LCD: Liquid Crystal Display.

28.) HSDPA: High speed down-link packet access.

29.) HSUPA: High-Speed Uplink Packet Access

30.) HSPA: High Speed Packet Access

31.) GPRS: General Packet Radio Service

32.) EDGE: Enhanced Data Rates for Global Evolution

33.)NFC: Near field communication

34.) OTG: on-the-go

35.) S-LCD: Super Liquid Crystal Display

36.) O.S: Operating system.

37.) SNS: Social network service

38.) H.S: HOTSPOT

39.) P.O.I: point of interest

40.)GPS: Global Positioning System

41.)DVD: Digital Video Disk / digital versatile disc

42.)DTP: Desk top publishing.

43.) DNSE: Digital natural sound engine .

44.) OVI: Ohio Video Intranet

45.)CDMA: Code Division Multiple Access

46.) WCDMA: Wide-band Code Division Multiple Access

47.)GSM: Global System for Mobile Communications

48.)WI-FI: Wireless Fidelity

49.) DIVX: Digital internet video access.

50.) .APK: authenticated public key.

51.) J2ME: java 2 micro edition

53.) DELL: Digital electronic link library.

54.)ACER: Acquisition Collaboration Experimentation Reflection

55.)RSS: Really simple syndication

56.) TFT: thin film transistor

57.) AMR: Adaptive Multi- Rate

58.) MPEG: moving pictures experts group

59.)IVRS: Interactive Voice Response System

60.) HP: Hewlett Packard..

Amplitude modulation and demodulation

AM is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent. As originally developed for the electric telephone, amplitude modulation was used to add audio information to the low-powered direct current flowing from a telephone transmitter to a receiver. As a simplified explanation, at the transmitting end, a telephone microphone was used to vary the strength of the transmitted current, according to the frequency and loudness of the sounds received. Then, at the receiving end of the telephone line, the transmitted electrical current affected an electromagnet, which strengthened and weakened in response to the strength of the current. In turn, the electromagnet-produced vibrations in the receiver diaphragm, thus reproducing the frequency and loudness of the sounds originally heard at the transmitter. In contrast to the telephone, in radio communication what is modulated is a continuous wave radio signal (carrier wave) produced by a radio transmitter. In its basic form, amplitude modulation produces a signal with power concentrated at the carrier frequency and in two adjacent sidebands. Each sideband is equal in bandwidth to that of the modulating signal and is a mirror image of the other. Amplitude modulation that results in two sidebands and a carrier is often called double sideband amplitude modulation (DSB-AM). Amplitude modulation is inefficient in terms of power usage and much of it is wasted. At least two-thirds of the power is concentrated in the carrier signal, which carries no useful information (beyond the fact that a signal is present); the remaining power is split between two identical sidebands, though only one of these is needed since they contain identical information. To increase transmitter efficiency, the carrier can be removed (suppressed) from the AM signal. This produces a reduced-carrier transmission or double-sideband suppressed carrier (DSBSC) signal. A suppressed-carrier amplitude modulation scheme is three times more power-efficient than traditional DSB-AM. If the carrier is only partially suppressed, a double-sideband reduced carrier
DSBRC) signal results. DSBSC and DSBRC signals need their carrier to be regenerated (by a beat frequency oscillator, for instance) to be demodulated using conventional techniques. Even greater efficiency is achieved—at the expense of increased transmitter and receiver complexity—by completely suppressing both the carrier and one of the sidebands. This is singlesideband modulation, widely used in amateur radio due to its efficient use of both power and bandwidth. A simple form of AM often used for digital communications is on-off keying, a type of amplitudeshift keying by which binary data is represented as the presence or absence of a carrier wave. This is commonly used at radio frequencies to transmit Morse code, referred to as continuous wave (CW) operation. As with other modulation indices, in AM, this quantity, also called modulation depth, indicates by how much the modulated variable varies around its 'original' level. For AM, it relates to the variations in the carrier amplitude and is defined as:

h=peak value of m(t)/A

Virtual instrumentation

                    ABSTRACT
Introduction:
Virtual instrumentation:
Virtual Instrumentation is the use of customizable software and modular measurement hardware to create user-defined measurement systems, called virtual instruments. The concept of a synthetic instrument is a subset of the virtual instrument concept. A synthetic instrument is a kind of virtual instrument that is purely software defined. A synthetic instrument performs a specific synthesis, analysis, or measurement function on completely generic, measurement agnostic hardware. Virtual instruments can still have measurement specific hardware, and tend to emphasize modular hardware approaches that facilitate this specificity. Hardware supporting synthetic instruments is by definition not specific to the measurement, nor is it necessarily (or usually) modular. Leveraging commercially available technologies, such as the PC and the analog to digital converter, virtual instrumentation has grown significantly since its inception in the late 1970s. Additionally, software packages like National Instruments' Lab VIEW and other graphical programming languages helped grow adoption by making it easier for non-programmers to develop systems. Lab VIEW: Lab VIEW (short for Laboratory Virtual Instrumentation Engineering Workbench) is a platform and development environment for a visual programming language from National Instruments. Originally released for the Apple Macintosh in 1986, Lab VIEW is commonly used for data acquisition, instrument control, and industrial automation on a variety of platforms including Microsoft Windows, various flavors of UNIX, Linux, and Mac OS.The programming language used in Lab VIEW, is a dataflow language. Execution is determined by the structure of a graphical block diagram

Lab VIEW
(short for Laboratory Virtual Instrumentation Engineering Workbench) is a platform and development environment for a visual programming language from National Instruments. Since this might be the case for multiple nodes simultaneously, it is inherently capable of parallel execution. Furthermore, Lab VIEW does not require type definition of the variables; the wire type is defined by the data-supplying node.   Communication systems:                          Starting from the easiest of the communication techniques and systems we move towards the most complicated and explore the use of virtual instrumentation and lab VIEW and its scope in creating a close simulation of these systems. The techniques covered begin from normal frequency translation to amplitude modulation leading to pulse modulation and finally culminates in the simulation of tougher topics like that of time and frequency division multiplexing and amplitude shift keying.   Experimental work   Lab VIEW ties the creation of user interfaces (called front panels) into the development cycle. Lab VIEW programs/subroutines are called virtual instruments (VIs). Each VI has three components:   Block diagram  Connector pane  Front panel      However, the front panel can also serve as a programmatic interface. This implies each VI can be easily tested before being embedded as a subroutine into a larger program                                                                     The graphical approach also allows non-programmers to build programs by simply dragging and dropping virtual representations of the lab equipment with which they are already familiar. The Lab VIEW programming environment, with the included examples and the documentation, makes it simpler to create small applications. This is a benefit on one side but there is also a certain danger of underestimating the expertise needed for good quality programming

Electronic voting machine

                      Abstract
According to Election Data Services the percentage of electronic voting machines per county doubled between 1998 and 2002 to 16 percent-, yet a full replacement of the traditional voting procedure is very unlikely. In its essence, an electronic voting machine is a computer assisted self-interviewing device (CASI) giving the voter the opportunity to review and change his/her vote before submitting it. The different types of voting machines allow for different kinds of interaction, such as using a touch screen technology, using a dial wheel, touching a paper panel, or pressing a button on an LCD screen. Each machine provides feedback for blank ballots and under-voting and prevents selecting more choices than the maximum allowed. Some machines even have advanced functions such as increasing the font for visually impaired voters and/or allowing for listening of the voting options rather than reading. The common features electronic voting machines share with CASI and ACASI devices allow for theoretical and empirical predictions of the advantages and disadvantages this technology can provide. The paper presents an overview of the different types of voting machines and based on established theories and results from CASI and ACASI studies, examines and compares characteristics of the machines currently used and computer-human interaction mechanisms, their potential effects, and unexplored applications. Furthermore, possibilities such as prediction of candidates’ name order effect, already existing in the literature, and computer literacy effect on voting are discussed

VOLTAGE AND POWER AMPLIFIERS

VOLTAGE AMPLIFIER:
The transistor with high β is used in the circuit. In other words, those transistor are employed which have thin base. 
The input resistance Rin of a transistor is sought to be quite low as compared to the collector load Rc. 
Relatively high load Rc is used in the collector.
To permit this condition, voltage amplifiers are always operated at low collector current.
If the collector current is small, we can use large Rc in the collector circuit.
POWER AMPLIFIER 
A power amplifier is required to deliver a large amount of power and as such it has to handle large current. 
The size of power transistor is made considerably larger in order to dissipate the heat produced in the transistor during operation. 
The base is made thicker to handle larger current

Differences between avalanche & zener breakdown

Zener breakdown: 
In Zener breakdown the electrostatic attraction between the negative electrons and a large positive voltage is so great that it pulls electrons out of their covalent bonds and away from their parent atoms.
ie: Electrons are transferred from the valence to the conduction band. In this situation the current can still be limited by the limited number of free electrons produced by the applied voltage so it is possible to cause Zener breakdown without damaging the semiconductor.
The important points are: 
*Both sides of PN junction are heavily doped 
*Depletion layer is narrow A strong electric field is produced 
*Large number of holes and electrons are produced
*Zener current is independent of applied voltage 
Avalanche breakdown
Avalanche breakdown occurs when the applied voltage is so large that electrons that are pulled from their covalent bonds are accelerated to great velocities. These electrons collide with the silicon atoms and knock off more electrons. These electrons are then also accelerated and subsequently collide with other atoms. Each collision produces more electrons which leads to more collisions etc. The current in the semiconductor rapidly increases and the material can quickly be destroyed.
The important points are: 
*Both sides of PN junction are lightly doped 
*Depletion layer is large 
*Electric field is not so strong   *Electron hole pairs are generated  Charge carriers acquire energy from the applied potential

Integrated Circuits

An integrated circuit (IC), sometimes called a chip or microchip, is a semiconductor wafer on which thousands or millions of tiny resistors, capacitors, and transistors are fabricated. An IC can function as an amplifier, oscillator, timer, counter, computer memory, or microprocessor. A particular IC is categorized as either linear analog or digital, depending on its intended application. IC's are are of Linear , digital and mixed types Linear ICs have continuously variable output (theoretically capable of attaining an infinite number of states) that depends on the input signal level. As the term implies, the output signal level is a linear function of the input signal level. Linear ICs are used as audio-frequency (AF) and radio-frequency (RF) amplifiers. The operational amplifier (op amp) is a common device in these applications. Digital ICs operate at only a few defined levels or states, rather than over a continuous range of signal amplitudes. These devices are used in computers, computer networks, modems, and frequency counters. The fundamental building blocks of digital ICs are logic gates, which work with binary data, that is, signals that have only two different states, called low (logic 0) and high (logic 1). Applications and Uses of Integrated Circuits
The advantages of Integrated Circuits are:
1. Very small size: Hundred times smaller than the discrete circuits.
2. Lesser weight: As large number of components can be packed into a single chip, weight is reduced
3. Reduced cost: The mass production technique has helped to reduce the price, 
4. High reliability: Due to absence of soldered connection, few interconnections and small temperature rise failure rate is low. 5. Low power requirement: As the size is small power consumption is less.
6. Easy replacement: In case of failure chip can easily be replaced.  Linear IC's also known as analog
Integrated circuits are:
1. Power amplifiers
2. Small-signal amplifiers
3. Operational amplifiers
4. Microwave amplifiers
5. RF and IF amplifiers
6. Voltage comparators
7. Multipliers
8. Radio receivers
9. Voltage regulators

Digital IC's are mostly used in computers. They are also referred as switching circuits because their input and output voltages are limited to two levels - high and low i.e. binary.
They include:
1. Flip-flops     
2. Logic gates
3. Timers
4. Counters
5. Multiplexers
6. Calculator chips
7. Memory chips
8. Clock chips
9. Microprocessors
10. Microcontrollers
11. Temperature sensors

Mixed type applications - cars (automotive controls), televisions, computers, microwaves, portable devices like laptops, MP3, play stations, cameras, cellular phones to ship equipments, aero planes, space craft’s. These are also used in switching telephone circuits and data processing. They also found applications in military equipments. The most common application of IC is digital watch which tells hour, second, minute, day and month. Another common but important application is scientific calculator which can perform basic functions like addition, subtraction, multiplication and division as well as complex functions like square root, cube, permutations, combinations , trigonometric functions, etc

ELECTRONIC DEVICES : Define Electronics & its application.

The world's reliance on electronics is so great that commentators claim people live in an "electronic age." People are surrounded by electronics—televisions, radios, computers, mobiles, Laptop and DVD players, along with products with major electric components, such as microwave ovens, refrigerators, and other kitchen appliances, automatic vehicles, Robotics, as well as hearing aids and medical instruments and numerous applications in industry. Definition: The branch of engineering which deals with current conduction through a Vacuum or Gas or Semiconductor is known as Electronics. An electronic device is that in which current flows through a vacuum or gas or semiconductor. This control of electrons is accomplished by devices that resist, carry, select, steer, switch, store, manipulate, and exploit the electron. Or  Electronics deals with electrical circuits that involve active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies. Commonly, electronic devices contain circuitry consisting primarily or exclusively of active semiconductors supplemented with passive elements; such a circuit is described as an electronic circuit. Pre Knowledge (Some of the basic definitions):  Passive Components: Capable of operating without an external power source. Typical passive components are resistors, capacitors, inductors. Active components: Requiring a source of power to operate.    Includes transistors (all types), integrated circuits (all types), TRIACs, SCRs, LEDs, etc. APPLICATIONS of Electronics: Electronic components: capacitor (C), cathode ray tube (CTR), diode (D), digital signal processor (DSP, field effect transistor (FET), integrated circuit (IC), junction gate field effect transistor (JFET), inductor (L), Liquid crystal display (LCD), light dependent resistor (LDR, light emitting diode (LED), Metal oxide semiconductor field effect transistor (MOSFET), transistor (Q), resistor (R), relay (RLA, RY), switch (SW), transformer (T), thermistor (TH), transistor (Tr), integrated circuit (U, IC), variable capacitor (VC), variable resistor (VR) and more

The Transistor Switch

Transistors are everywhere. You can’t avoid them as you move through your
daily tasks. For example, almost all industrial controls, and even your MP3
player, stereo, and television may use transistors as switches.
In Chapter 3, you saw how a transistor can be turnedONand OFF, similar to
a mechanical switch. Computers work with Boolean algebra, which uses only
two logic states—TRUE and FALSE. These two states are easily represented
electronically by a transistor that isONorOFF. Therefore, the transistor switch
is used extensively in computers. In fact, the logic portions of microprocessors
(the brains of computers) consist entirely of transistor switches.
This chapter introduces the transistor’s simple andwidespread application–
switching, with emphasis on the bipolar junction transistor (BJT).
When you complete this chapter, you will be able to do the following:
Calculate the base resistance, which turns a transistor ON and OFF.
Explain how one transistor will turn another ON and OFF.
Calculate various currents and resistances in simple transistor switching
circuits.
Calculate various resistances and currents in switching circuits, which
contain two transistors.
Compare the switching action of a junction field effect transistor (JFET) to
a BJT.

Introduction to the Transistor

The transistor is undoubtedly the most important modern electronic component
because it has enabled great and profound changes in electronics and in
our daily lives since its discovery in 1948.
This chapter introduces the transistor as an electronic component that acts
similarly to a simple mechanical switch, and, in fact, it is actually used as a
switch in many modern electronic devices.Atransistor can be made to conduct
or not conduct an electric current — exactly what a mechanical switch does.
Most transistors used in electronic circuits are bipolar junction transistors
(BJT), commonly referred to as bipolar transistors, junction field effect transistors
(JFET), or metal oxide silicon field effect transistors (MOSFET). This chapter
(along with Chapters 4 and 8) illustrates how BJTs and JFETs function and
how they are used in electronic circuits. Because JFETs and MOSFETs function
in similar fashion, MOSFETs are not covered here.
An experiment in this chapter will help you to build a simple one-transistor
switching circuit. You can easily set up this circuit on a home workbench.
You should take the time to obtain the few components required and actually
perform the experiment of building and operating the circuit.
In Chapter 4, you will continue to study switching designs and the operation
of the transistor as a switch. In Chapter 8, you learn how a transistor can be
made to operate as an amplifier. In this mode, the transistor produces an
output that is a magnified version of an input signal, which is useful because
many electronic signals require amplification. These chapters taken together
present an easy introduction to how transistors function and how they are
used in basic electronic circuits.
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The Diode

The main characteristic of a diode is that it conducts electricity in one direction
only. Historically, the first vacuum tube was a diode; it was also known
as a rectifier. The modern diode is a semiconductor device. It is used in all
applications where the older vacuum tube diode was used, but it has the
advantages of being much smaller, easier to use, and less expensive.
A semiconductor is a crystalline material that, depending on the conditions,
can act as a conductor (allowing the flow of electric current) or an insulator
(preventing the flow of electric current). Techniques have been developed to
customize the electrical properties of adjacent regions of semiconductor crystals,
which allow the manufacture of very small diodes, as well as transistors
and integrated circuits.
When you complete this chapter you will be able to do the following:
Specify the uses of diodes in DC circuits
Determine from a circuit diagram whether a diode is forward or reverse
biased
Recognize the characteristic V-I curve for a diode
Specify the knee voltage for a silicon or a germanium diode
Calculate current and power dissipation in a diode
Define diode breakdown
Differentiate between zeners and other diodes
Determine when a diode can be considered ‘‘perfect’’

RFID BASED SECURED ACCESS SYSTEM USING 8051 MICROCONTROLLER (AT89C51)

                                                               ABSTRACT
RFID based Secured access system implemented on 8051 microcontroller . This is a very useful application of RFID (Radio-frequency identification) and is very commonly used in institutes, offices, homes and so on. An RFID system consists of a reader device and a transponder. A transponder or tag has a unique serial number which is identified by the reader. Here RFID has been interfaced with AT89C51 to provide secured access. The relevant messages are also displayed on a 16x2 LCD.
RFID automated access for door controls to buildings, departments, rooms, secured closets (wiring, PBX, etc.) and cabinets is very cost effective and secure to use. Many people do not realize how easy it is to implement card access systems such as card access door or doors using RFID readers and RFID Cards or Keyfobs for Secured Access Control Management. You can even use smart readers for computer rooms and securing individual computers.
In fact access based entrance and exits using access smart technology is rapidly becoming the way of the future for many businesses, government buildings, hospitals, museums and other establishments requiring secured but easy to control access solutions. Access based systems use either 125 kHz RFID or 13.56 MHz RFID readers, cards and keyfobs.
Features:
􀂾 Low power requirement.
􀂾 Excellent characters appearance.
􀂾 Reliability.
􀂾 Lower cost.
In our project we are implementing the RFID based secured access system by using microcontroller. The system communicates with an administrator PC via a serial communications link and HyperTerminal. RFID technology is based on the concept of magnetic coupling, which is the principle that current flowing in one circuit can induce current flow in
another circuit through a magnetic field generated in the space between the circuits.