The Schottky Diode
The Schottky Diode:
At lower frequencies an ordinary diode can easily turn off when bias changes from forward to reverse. At higher frequencies, it can not turn off fast enough to prevent noticeable current during part of the reverse half cycle. The above problem can be solved using Schottky diode.
The Schottky diode uses a metal like gold, silver or platinum on one side of the junction and doped silicon (typically "N" type) on the other side. When the diode is forward biased, free electrons on the N type semiconductor side can gain enough energy to travel in larger orbits. Because of this free electrons can cross the junction and enter the metal producing a large forward current. Since the metal has no holes, there in no charge storage and no reverse recovery time. So lack of charge storage means that Schottky diode can be switched off faster than P-N Junction diode.
The important application of Schottky diode is in digital computer where fa st switching of logic circuit is required. The following fig. shows the symbols for Schottky diode.
Variable capacitance diode
The circuit symbol is . 
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Writer : delon |
28 Jan 2011 Fri  
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