The Coming Television RevolutionWritten by Terry Mitchell
The revolution is just getting started and will begin to make its mark this year. By 2010, it will begin to take off. By 2025, it will be standard for all TV viewing. It's called Internet Protocol Television, or IPTV for short. IPTV works with a set-top box connected to any broadband interface and to a TV. It will allow users to choose among thousands (and eventually hundreds of thousands) of hours of programming, including movies, sports, classic TV, etc., and download their selections from internet to hard drive of set-top box. Initially, set-top box hard drives will be able to store up to 300 hours of programming at a time, but capacity will expand as technology becomes more refined. Also, download times will become shorter and shorter as broadband connection speeds become faster and faster. Eventually, a two-hour movie will be fully downloadable in a couple of minutes. Once programs are downloaded to hard drive, they can be viewed on connected TV at any time via a DVR-type interface provided by set-top box. Besides convenience of an all video-on-demand (VOD) environment, IPTV will provide a much wider range of programming than broadcast, cable, and satellite TV, or even major video chains, could ever provide. Because programming is available from internet, it will be almost completely unlimited and unconstrained. Programming from all over world will be available along with every imaginable genre of niche programming. Also, previously unreleased independent films that have been sitting on shelves for years due to lack of a distribution source will suddenly become available to masses via IPTV. Films that previously could not be made at all will become a reality and be available on IPTV services. Long forgotten films and TV shows will have new life breathed into them by IPTV. To top it all off, much of this programming will be eventually be available in high definition (HDTV)! Most IPTV platforms will be divided into "channels", but not same kind of channels that we have grown accustomed to with traditional TV services. In this case, a "channel" is defined as a division of an IPTV service by individual content provider. Each content provider carried by a given IPTV platform will have its own guidelines for delivering programming on its channel. Some will provide their content for free to everyone who owns a given IPTV product. Some will be subscription based, i.e., everything on their channels will be available for a monthly or annual subscription. Others will be all pay-per-view. Still others will provide a combination of all of above.
Vacation Break for Electrical MachinesWritten by Thomas Yoon
Are you overloaded? Have you become a part of highly stressed modern working environment? You may need a break - a vacation, a change in environment, a change of pace...
Similarly, machines can be overloaded too. Those that were designed for a particular system are often pushed to their limits when new requirements emerge.
Just like final straw that breaks camel's back, electrical machines too, can reach their breaking point. If there is no vacation for them, they will burn.
Fuses and circuit breakers are designed to stop current in a circuit before any damage can occur - create a vacation or a break for them.
A circuit breaker is one of ways to prevent motors (or other electrical machines) from burning due to overloading. All electrical motors produce heat when running. At time of a fault, this heat builds up at a much higher rate than it can be dissipated. This can result in damaged equipment, fire or even explosion.
The electrical protective device like circuit breaker is designed to de-energize circuit before this heat level becomes dangerous.
There are basically 2 means of activating a break - thermally (heat) or magnetically.
Thermal circuit breakers make use of bimetallic strips that will bend due to different expansion rates of each of metals in strip. The bending of strip will move a tripping mechanism latch that will then open up contacts of circuit breaker.
Because bimetallic strips take time to heat up and bend, this type of tripping device is used for tripping prolonged overloaded situations. The setting for breaking circuit at a particular overload value can be adjusted.