CAPACITORS

FUNCTION
Capacitors store electric charge. They are used with resistors in timing circuits because it takes time for a capacitor to fill with charge. They are used to smooth varying DC supplies by acting as a reservoir of charge. They are also used in filter circuits because capacitors easily pass AC (changing) signals but they block DC (constant) signals.

CAPACITANCE

This is a measure of a capacitor's ability to store charge. A large capacitance means that more charge can be stored. Capacitance is measured in farads, symbol F. However 1F is very large, so prefixes are used to show the smaller values.
Three prefixes (multipliers) are used, µ (micro), n (nano) and p (pico):
µ means 10-6 (millionth), so 1000000µF = 1F
n means 10-9 (thousand-millionth), so 1000nF = 1µF
p means 10-12 (million-millionth), so 1000pF = 1nF
Capacitor values can be very difficult to find because there are many types of capacitor with different labelling systems!
There are many types of capacitor but they can be split into two groups, polarised and unpolarised. Each group has its own circuit symbol.


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Light Emitting Diodes (LEDs)

FunctionLEDs emit light when an electric current passes through them.
Connecting and soldering LEDs must be connected the correct way round, the diagram may be labelled a or + for anode and k or - for cathode (yes, it really is k, not c, for cathode!). The cathode is the short lead and there may be a slight flat on the body of round LEDs. If you can see inside the LED the cathode is the larger electrode (but this is not an official identification method).
LEDs can be damaged by heat when soldering, but the risk is small unless you are very slow. No special precautions are needed for soldering most LEDs.

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HISTORY OF UNIVERSE IN 200 WORDS

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Quantum fluctuation. Inflation. Expansion. Strong nuclear interaction. Particle-antiparticle annihilation. Deuterium and helium production. Density perturbations. Recombination. Blackbody radiation. Local contraction. Cluster formation. Reionization? Violent relaxation. Virialization. Biased galaxy formation? Turbulent fragmentation. Contraction. Ionization. Compression. Opaque hydrogen. Massive star formation. Deuterium ignition. Hydrogen fusion. Hydrogen depletion. Core contraction. Envelope expansion. Helium fusion. Carbon, oxygen, and silicon fusion. Iron production. Implosion. Supernova explosion. Metals injection. Star formation. Supernova explosions. Star formation. Condensation. Planetesimal accretion. Planetary differentiation. Crust solidification. Volatile gas expulsion. Water condensation. Water dissociation. Ozone production. Ultraviolet absorption. Photosynthetic unicellular organisms. Oxidation. Mutation. Natural selection and evolution. Respiration. Cell differentiation. Sexual reproduction. Fossilization. Land exploration. Dinosaur extinction. Mammal expansion. Glaciation. Homo sapiens manifestation. Animal domestication. Food surplus production. Civilization! Innovation. Exploration. Religion. Warring nations. Empire creation and destruction. Exploration. Colonization. Taxation without representation. Revolution. Constitution. Election. Expansion. Industrialization. Rebellion. Emancipation Proclamation. Invention. Mass production. Urbanization. Immigration. World conflagration. League of Nations. Suffrage extension. Depression. World conflagration. Fission explosions. United Nations. Space exploration. Assassinations. Lunar excursions. Resignation. Computerization. World Trade Organization. Terrorism. Internet expansion. Reunification. Dissolution. World-Wide Web creation. Composition. Extrapolation? I think it is an extremely good piece of writing. What do you

AJAX

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First thing first, i am not goin to explain the AJAX at core level or at OS level. I am a beginner to this technology. so, i will try my best to explain, how can u build ur website on AJAX technology. OK. u can find loads of material on web for this topic. so i am not going in detail of this theory. U will feel comfortable if i cud explain the implementation. right!! but lets some basics.
AJAX: Asynchronous Javascript and XML.(try wikepedia for more)
What did u feel the difference, when u open a gmail account and yahoo mail account? (Don't worry yahoo is going AJAX very soon) the difference is: each time u open a new mail in yahoo, the whole page refreshes, however in gmail the only some part of the page changes its content. right!! this is the benefit of AJAX. u didn't need to refresh the whole page. it means, if u want to change a part of any web page, just get the data for that part using the network link. so u r saving the bandwidth of ur link. on the other hand if u will refresh the whole page for the change of a part, it doesn't make any sense. but this is the way most of the websites work. Soooo, switch to AJAX technology. HOW? i will TRY to explain the method. the whole method by which u can experience and learn the AJAX technology.The mantra behind this technology is Javascript and XML. nothing is new here. javascript and xml are known for years but i don't know why this technology is appearing, now. Sine i had worked on PHP, Javascript, XML, and HTML using APACHE server and MYSQL database server, so i will explain this technology using all these languages. don't woory, i will explain from basics so u must have some basic knowledge of PHP, JAVASCRIPT and XML(with html, of course). rest u can leave on me (and goooogle!!!). i will explain how to setup apache and mysql server on your windows machine. So, if u want to learn with me, in meantime u shud try to learn basics of PHP and Javascript(1-2 chapter of any book will be suffice). AJAX works like: ur client page will make request to server using javascript. the javascript will form the request packet using XML and send it to server, where the server will process this xml packet and extract the required information. this information will further processed by php and then reply will be send to client machine using xml packet. the javascript at client machine will recv the xml packet (and sometime html information) which will be displayed at client side page. THATS IT. so next time i will explain how to setup ur server and a small example. be ready to MAKE UR WEBSITE based on AJAX.i invite those ppl who knows more abt this technology. I want to learn and you too. so plz share ur suggestions and knowledge