DIODES:
Diode Definition:
It is an electronic component that
restrict flow of charge carriers. It allows the current
to flow in unidirection i.e one direction but blocks it
in another direction. There is a small voltage across
the diode about 0.7 v called forward voltage drop and
also a reverse voltage which a diode can resist about
50V. The diodes have cathode and anode hence must be put
correct way round. As per the symbol of diode the
current flows in that direction. Diodes are commonly
made from either Silicon or Germanium.
Types of Diodes
Thermionic Diodes
Thermionic diodes are vacuum tubes,
which are nothing but electrodes surrounded by a vacuum
within a glass envelope similar in appearance to
incandescent light bulbs.
Semiconductors diodes
Presently many diodes are based on
semiconductor p-n junctions. In a p-n diode,
conventional current can flow from the p-type side (or
the anode) to the n-type side (that is the cathode), but
cannot flow in the opposite direction. Another type of
semiconductor diode, the Scotty diode, is formed by the
contact between a metal and a semiconductor rather than
by a p-n junction.
Zener Diodes
Diodes that can be made to conduct
backwards. This effect we call it a Zener breakdown,
which occurs at a accurately defined voltage, allowing
the diode to be used as a precision voltage reference.
The minimum voltage available is 2.4V. Mostly Power
ratings of 400mW and 1.3W..
Photo Diodes
It can be used as solar cells and in
photometry.
LED's Light Emitting Diodes
Used in making sign boards or
for measuring temperature etc
Diodes Manufactures Links
