Understanding SMPS

Friday, February 6, 2009

As all we know that,SMPS is one of the important part of any computer system and after that only very few people know about it.An SMPS(Switched Mode Power Supply) is an electronic power unit that is used as a switching regulator.The main task of any SMPS is to switch the power supply between the saturation (full on) and cutoff (completely off) with a variable duty cycle whose average is the desired output voltage.After this the resulting rectangular waveform that is formed passed through a combination of a capacitor and inductor.The main advantage of this method is greater efficiency because the switching transistor dissipates little power in the saturated state and the off state compared to the semi conducting state (active region).In addition to these advantages,SMPS is light in weight and in smaller size so that it can easily fit into your pc.On the other hand it also have some disadvantages like greater complexity, the generation of high amplitude, high frequency energy that the low-pass filter must block to avoid EMI and a ripple voltage at the switching frequency and the harmonic frequencies thereof.

SMPS can be classified into four types according to the input and output waveforms, as follows.

AC in, DC out: rectifier, off-line converter input stage.
DC in, DC out: voltage converter, or current converter, or DC to DC converter
AC in, AC out: frequency changer, cycloconverter
DC in, AC out: inverter
AC and DC are abbreviations for alternating current and direct current.

Understanding Spyware

Thursday, February 5, 2009

Spyware is Internet jargon for Advertising Supported software (Ad-ware). It is a way for shareware authors to make money from a product, other than by selling it to the users. There are several large media companies that offer them to place banner ads in their products in exchange for a portion of the revenue from banner sales. This way, you don't have to pay for the software and the developers are still getting paid. If you find the banners annoying, there is usually an option to remove them, by paying the regular licensing fee.

There are thousands out there, new ones are added to the list everyday. But here are a few:Alexa, Aureate/Radiate, BargainBuddy, ClickTillUWin, Conducent Timesink, Cydoor, Comet Cursor, eZula/KaZaa Toptext, Flashpoint/Flashtrack, Flyswat, Gator, GoHip, Hotbar, ISTbar, Lions Pride Enterprises/Blazing Logic/Trek Blue, Lop (C2Media), Mattel Brodcast, Morpheus, NewDotNet, Realplayer, Songspy, Xupiter, Web3000, WebHancer, Windows Messenger Service.

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