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Introduction of NETWORKING..

Question: What is (Wireless / Computer) Networking?

Answer: In the world of computers, networking is the practice of linking two or more computing devices together for the purpose of sharing data. Networks are built with a mix of computer hardware and computer software.

Introduction to Network Types:

One way to categorize the different types of computer network designs is by their scope or scale. For historical reasons, the networking industry refers to nearly every type of design as some kind of area network. Common examples of area network types are:
LAN - Local Area Network
WLAN - Wireless Local Area Network
WAN - Wide Area Network
MAN - Metropolitan Area Network
SAN - Storage Area Network, System Area Network, Server Area Network, or sometimes Small Area Network
CAN - Campus Area Network, Controller Area Network, or sometimes Cluster Area Network
PAN - Personal Area Network
DAN - Desk Area Network LAN and WAN were the original categories of area networks, while the others have gradually emerged over many years of technology evolution.
Note that these network types are a separate concept from network topologies such as bus, ring and star.
LAN - Local Area NetworkA LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. In TCP/IP networking, a LAN is often but not always implemented as a single IP subnet.
In addition to operating in a limited space, LANs are also typically owned, controlled, and managed by a single person or organization. They also tend to use certain connectivity technologies, primarily Ethernet and Token Ring.
WAN - Wide Area NetworkAs the term implies, a WAN spans a large physical distance. The Internet is the largest WAN, spanning the Earth.
A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to a WAN. In IP networking, the router maintains both a LAN address and a WAN address.
A WAN differs from a LAN in several important ways. Most WANs (like the Internet) are not owned by any one organization but rather exist under collective or distributed ownership and management. WANs tend to use technology like ATM, Frame Relay and X.25 for connectivity over the longer distances

Source:http://compnetworking.about.com/cs/basicnetworking/f/whatsnetworking.htm

History Of Telecom

HISTORY OF TELECOMMUNICATION

A replica of one of Chappe's semaphore towers
In the Middle Ages, chains of beacons were commonly used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could only pass a single bit of information, so the meaning of the message such as "the enemy has been sighted" had to be agreed upon in advance. One notable instance of their use was during the Spanish Armada, when a beacon chain relayed a signal from Plymouth to London signalling the arrival of Spanish ships.[1]
In 1792, Claude Chappe, a French engineer, built the first fixed visual telegraphy system (or semaphore line) between Lille and Paris.[2] However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres (six to nineteen miles). As a result of competition from the electrical telegraph, the last commercial line was abandoned in 1880.[3]
[edit] Telegraph and telephone
The first commercial electrical telegraph was constructed by Sir Charles Wheatstone and Sir William Fothergill Cooke and opened on 9 April 1839. Both Wheatstone and Cooke viewed their device as "an improvement to the [existing] electromagnetic telegraph" not as a new device.[4]
Samuel Morse independently developed a version of the electrical telegraph that he unsuccessfully demonstrated on 2 September 1837. His code was an important advance over Wheatstone's signaling method. The first transatlantic telegraph cable was successfully completed on 27 July 1866, allowing transatlantic telecommunication for the first time.[5]
The conventional telephone was invented independently by Alexander Bell and Elisha Gray in 1876.[6] Antonio Meucci invented the first device that allowed the electrical transmission of voice over a line in 1849. However Meucci's device was of little practical value because it relied upon the electrophonic effect and thus required users to place the receiver in their mouth to “hear” what was being said. The first commercial telephone services were set up in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven and London
[edit] Radio and television
In 1832, James Lindsay gave a classroom demonstration of wireless telegraphy to his students. By 1854, he was able to demonstrate a transmission across the Firth of Tay from Dundee, Scotland to Woodhaven, a distance of two miles (3 km), using water as the transmission medium.[10] In December 1901, Guglielmo Marconi established wireless communication between St. John's, Newfoundland (Canada) and Poldhu, Cornwall (England), earning him the 1909 Nobel Prize in physics (which he shared with Karl Braun).[11] However small-scale radio communication had already been demonstrated in 1893 by Nikola Tesla in a presentation to the National Electric Light Association.[12]
On 25 March 1925, John Logie Baird was able to demonstrate the transmission of moving pictures at the London department store Selfridges. Baird's device relied upon the Nipkow disk and thus became known as the mechanical television. It formed the basis of experimental broadcasts done by the British Broadcasting Corporation beginning 30 September 1929.[13] However, for most of the twentieth century televisions depended upon the cathode ray tube invented by Karl Braun. The first version of such a television to show promise was produced by Philo Farnsworth and demonstrated to his family on 7 September 1927.[14]
[edit] Computer networks and the Internet
On 11 September 1940, George Stibitz was able to transmit problems using teletype to his Complex Number Calculator in New York and receive the computed results back at Dartmouth College in New Hampshire.[15] This configuration of a centralized computer or mainframe with remote dumb terminals remained popular throughout the 1950s. However, it was not until the 1960s that researchers started to investigate packet switching — a technology that would allow chunks of data to be sent to different computers without first passing through a centralized mainframe. A four-node network emerged on 5 December 1969; this network would become ARPANET, which by 1981 would consist of 213 nodes.
ARPANET's development centred around the Request for Comment process and on 7 April 1969, RFC 1 was published. This process is important because ARPANET would eventually merge with other networks to form the Internet and many of the protocols the Internet relies upon today were specified through the Request for Comment process. In September 1981, RFC 791 introduced the Internet Protocol v4 (IPv4) and RFC 793 introduced the Transmission Control Protocol (TCP) — thus creating the TCP/IP protocol that much of the Internet relies upon today.
However, not all important developments were made through the Request for Comment process. Two popular link protocols for local area networks (LANs) also appeared in the 1970s. A patent for the token ring protocol was filed by Olof Soderblom on 29 October 1974 and a paper on the Ethernet protocol was published by Robert Metcalfe and David Boggs in the July 1976 issue of Communications of the ACM.

Nuclear Power Plant Process.

source: www.youtube.com

Nuclear Power Plant Process..

This video contains information about cycle of NUCLEAR POWER PLANT.

how it works?

Working Principle?

Complete Reaction and Cycle?

Electrical Instruments

Here is a photo of a very simple eddy current AC motor I put together. I think this one wins the prize for the Simplest AC Motor you can make. It works great and is very easy to build. I found the original plans in a book titled: "Physics Demonstration Experiments" by Harry F. Meiners, Vol 2, Ronald Press Co., NY, 1970, LCCC #69-14674. With some experimentation, I found that the can spins faster when the nut is on the end of the bolt than when the nut is removed. What do you think will happen if the rotor is moved to the other side of the bolt? It consists of a coil mounted onto a 3/4" bolt. The coil is about 100' of 20AWG wire, on a form about 1.5" long, with a dc resistance of about 1.2 ohms, and an inductance of about 2.4mH as an air-core inductor. The voltage supplied to the coil is 19Vac from a plug-in transformer and supplies about 2.5Aac to the coil. The rotor is an aluminum film canister (today they use plastic, but you might still find a few of these around - ask your friends) with a dimple in the bottom of it, resting on a pencil. (I figured that the graphite in the pencil will lubricate the rotor.
The eddy current motor on the left has two rotors, they spin in opposite directions. The set-up on the right shows a variac, multimeter, eddy current motor, and a calibrated strobe. With this, we could plot speed vs. voltage. We found that the rotor would spin about 1000 rpm with 120V applied to it. Can't keep it there for long, since the coil and bolt get real hot. On these two coils, a smaller diameter wire was used, so the dc resistance was about 11.2 ohms, and 24mH as an air-core inductor. With this, we could apply 120Vac to it and only 2 amps would be drawn.
A Shaded Pole AC Motor

Here is a photo of a typical shaded pole motor. See the close-up of the notch in the laminations and the extra heavy winding of two turns creating the phase differenc

e between the two sections of the laminations, giving the magnetic field a directional motion. The rotor spins CW as seen from the end with the screw on the shaft. Motors like this are used in thousands of applications.
A Universal Motor

And here is a photo of a universal motor. It has brushes like a DC motor, but will operate on AC or DC.