Power Semiconductor Devices Essay -- Power Conversion Essays

Power Semiconductor Devices Introduction Today there are many power semiconductor devices used in different applications of power conversion. The diode is one of the oldest semiconductors devices and is still wildly used today in power electronics. Diodes are found in virtually all power converts in one form or another. For this reason our discussion will be focused on the application of power diodes. Power Diodes are two terminal electronic devices that permit current flow in predominantly one direction. Diodes are composed of differently doped silicon or germanium bounded together at a junction. Purpose As an Electrical Engineering specializing in Power Electronics it is important to understanding the application of different types of diodes in power electronics. The technology behind the development of pn junctions and solid state devices is continuously advancing. This is why it is important to be informed of the most modern advances of one of the world’s oldest power semiconductor devices. This paper will focus on the construction and ratings of various types of power diodes to convey the importance diodes have power electronics. Power Diodes: Power diodes are successors to the very first semiconductor devices. Power diodes are mainly used as uncontrolled rectifiers to convert single-phase or three- phase AC voltage to a rippled DC voltage. Typically they are constructed of a mixture of differently doped silicon or germanium. Most common are the silicon diodes because they can operate at higher currents and junction temperatures then germanium diodes. All diodes are devices that conduct current in only one direction. Whenever the voltage on the anode is positive with respect to the cathode, the dio... ...e a diode that will satisfy the requirements of the circuit while increasing overall circuit efficiency and maintaining reliability. Through improved modern design techniques diodes are no longer a weak component, and are becoming more important in power electronics with the increase demand for higher power quality and power efficiency. Works Cited: N. Mohan, T.M. Undeland, W.P. Robbins, â€Å"Power Electronics†, John Wiley & Sons, Inc.  © 2003 Timothy L. Skvarenina, â€Å"The Power Electronics Handbook† CRC Press LLC  © 2002 Materials Research Society Symposium Proceedings Volume 483, â€Å"Power Semiconductor Materials and Devices† Materials Research Society  © 1998 â€Å"Dura-Bilt5i MV Engineering Reference Book†, GE Toshiba Automation Systems, U.S.A.  © 2003 Kilowatt Classroom: Electrical Training Seminars - Web Site Home Page http://www.kilowattclassroom.com/

Motorcycle Diaries Essay Essay

The movie â€Å"The Motorcycle Diaries† is very interesting in a way that, Ernesto not only takes a journey across Latin America but he also experiences a mental journey. His way of thinking and outlook on life changes drastically and this is illustrated all throughout the movie. He also discovers a great deal about life in Latin America that affects him in a way nothing else has before. Ernesto’s mental journey becomes clearer towards the end of the movie. It shows that he has changed and now has realized he can make a huge difference in many others lives. At first in the movie he and his companion do whatever it takes to rest and eat because at this time all they were concerned about was traveling around America. As more time passes, Ernesto gets incredibly serious and starts to show much concern for the people they meet. An example is when they meet the older gentleman and he asked them to take a look at the lump on his neck. This was when Ernesto told him that it was not just any ordinary lump, but it was indeed a tumor. Ernesto then suggests he go to the hospital, while Ernesto’s friend tells the man it’s nothing just so they can have a place to stay for the night. I believe this was a very bold move for him because it cost them their shelter for the night. By doing this he really demonstrates that he himself is more concerned about others lives then petty things, such as where he will sleep for the night. Although Latin America looks like a peaceful pleasant country, many people are very ill. Ernesto discovers this when he visits the one village. He experiences how truly sick they all are from all the disease. Up until this point he had pitied himself for having asthma, but now he has become thankful that he has good health. You can tell how caring and warm-hearted he has become at this point in the movie. An example of this is when he refuses to wear the gloves because he feels cruel doing so, as if he’d be acting as if they were animals not everyday people, the same as himself. From the day he stepped foot in this village he never treated any of the patients different and they loved being around him. It was amazing because you could just tell how much it meant to them for him to be there. All and all Ernesto learned and discovered a great deal within this film. He  changed much in his life and his attitude toward the world through this one journey. I believe there is one thing he will always take with him from this experience. That one thing is that he learned that he can make a huge difference in the lives of many just by caring enough to do so.

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