tag:blogger.com,1999:blog-51515615787964267232012-02-16T16:22:25.663-08:00when u try to start a course in electronics a basic knowledge of it is required... with this prerequisite tips u can enter the world of electronics without fear and be master in conquering what u need...best of luckbharathhttp://www.blogger.com/profile/13052943566918372524noreply@blogger.comBlogger21100tag:blogger.com,1999:blog-5151561578796426723.post-29590065188365102232007-05-20T06:44:00.000-07:002007-05-20T06:52:45.032-07:00<ul><li>why are impurities added to a pure semiconductor</li><li>are semiconductors crystalline or amorphous?</li><li>what is conductivity</li><li>how are two semiconductors joined? or how is a junction physically formed?</li><li>what is biasing?</li><li>why is biasing needed?</li><li>what is transistor?</li><li>full form of transistor</li><li>why is it called so?</li><li>what is q-point?</li></ul><br />These are some basic questions most of the people ask in viva and other interviews so make sure you know them first.<div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/5151561578796426723-2959006518836510223?l=brushupelectronics.blogspot.com' alt='' /></div>bharathhttp://www.blogger.com/profile/13052943566918372524noreply@blogger.com0tag:blogger.com,1999:blog-5151561578796426723.post-35984886672322045642007-05-20T05:55:00.000-07:002007-05-20T06:43:52.255-07:00so first you need to know to know the following terms..<br /><ul><li>semiconductor</li><li>intrinsic and extrinsic semiconductor</li><li>impurities</li><li>junction</li><li>junction formation</li><li>minority carriers</li><li>majority carriers</li><li>diode</li><li>transistor</li></ul>With these terms in your grasp you can freely look into any of the prescribed text book for basic electronics.... so we start by defining these terms.<br /><br /><span style="font-weight: bold;">SEMICONDUCTOR:</span><br /><span style="font-weight: bold;"><br /></span>These type of materials are classified as per the materials resistance be that of a thermal resistance or electrical resistance... so first look at the definition of resistance if u don't know.<br />we are more concerned with the electric resistance are we dealing with it. So a semiconductor has a resistance in between that of a conductor and insulator. some semi conducting materials are silicon, germanium, gallium arsenide , indium phosphate. These semi conducting materials are divided into two types intrinsic and extrinsic. Intrinsic semiconductor is the one in its purest form and an extrinsic semiconductor is the one where impurities are added. Impurities are two types trivalent or pentavalent. these will be discussed in the junctions.<br /><br /><span style="font-weight: bold;"> Junction and its formation :</span><br /><span style="font-weight: bold;"><span style="font-weight: bold;"><br />A </span></span> semiconductor junction is formed when two semiconductors of different impurities are joined.<br />The process of adding an impurity is called doping. When trivalent impurities are added a p-type semiconductor is formed where holes act as current carriers...** refer the term holes if u don't know it**. When pentavalent impurities are present in a semiconductor a n-type is formed where electrons act as current carriers. So when p type and n-type semiconductors are joined a junction is formed.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://bp2.blogger.com/_g0DRQ8dkQEU/RlBPrWujeMI/AAAAAAAAAAg/xlAUuTrJyDU/s1600-h/pn.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://bp2.blogger.com/_g0DRQ8dkQEU/RlBPrWujeMI/AAAAAAAAAAg/xlAUuTrJyDU/s320/pn.gif" alt="" id="BLOGGER_PHOTO_ID_5066637187045619906" border="0" /></a><br />the figure to the right indicates the energy bands of a diode. you can learn about the bands and the formation of forbidden band once u enter your world. More coming up. Check out the site for basic questions asked in viva and other general interviews<br /><br /><span style="font-weight: bold;"><span style="font-weight: bold;"></span><br /></span><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/5151561578796426723-3598488667232204564?l=brushupelectronics.blogspot.com' alt='' /></div>bharathhttp://www.blogger.com/profile/13052943566918372524noreply@blogger.com0