Introduction To Diodes.

 

     Diodes are electrical components that are made up of semiconductors,they are made from a junction of a PN semiconductor material.diodes allows current in only one direction,that is they only allow current to move in one direction when connected in a forward bias and blocks it when connected in reverse bias

   It is a two terminal electronic component that conducts electric current in only one direction.The term usually refer to a semiconductor diode,the most common type today which is Crystal of semiconductor connected to a two electrical terminals, a p-N junction.

A vacuum tube diode,now little used,is a vacuum tube with two electrodes; a plate and a cathode.

The most common function of a diode is to allow current in one direction (called forward bias also know as forward direction) while blocking current in the opposite direction (the reverse direction or bias).Thus,the diode can be thought of as an electronic version of a check valve.This unidirectional behavior is called rectification and is used to convert alternating current to direct current,and extract modulation from radio signals  in radio receivers.However,diodes can have more complicated behavior than this simple on-off action,due to their complex no linear electrical characteristics, which can be tailored by varying the construction of their P-N junction. These are exploited in special purpose diodes that perform many different functions. Diodes are used in regulating voltage (zener diodes), electronically tune radio and TV receivers (veractor diodes),generate radio frequency oscillation (tunnel diodes) and produce light (light emitting diodes).

    Diodes were the first semiconductors electronic devices.The discovery of crystals rectifying abilities was made by a German physicist Ferdinand Braun in 1874.The first semiconductor diode, called whisker diodes were made of crystals of minerals such as Galena.  Today most diodes are made from sillicon,but other semiconductors such as germanium are sometimes used.

 Therefore diodes has much applications in circuits which includes:

1.converting AC to DC: they are called rectifier when used to convert AC to DC.

2.lightning 

3.stabilizing voltage

4.switching

5.circuit protection

6.radio wave generation

7.LASER generation

8.producing electricity from light etc.

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