Types of Diode

Types of diode

Diode is a one way valve, it mean that it allow current on one direction and block current in the other direction.

it has two terminal: anode and cathode 

and has two state: 

1-forward bias: connect positive rail of supply to anode and negative rail to cathode in that condition diode allow current but has voltage drop across it depend on material of diode.

2-Reverse bias: connect positive rail of supply to cathode and negative rail to anode in that condition diode block current and it act like open circuit with very small leakage current.

Diode generally made of silicon or germanium , these three material have a voltage drop 0.7 , 0.3 respectively.

let's discuss types of diode and application of every type.

Normal Diode:
It also called general purpose diode. it have meduim to high volltage drop, low current rating , low speed rectifier and inefficient for square wave more than 15kHZ.

Power Diode:

It also called rectifier diode . it has high current rating in ampere depend on the required application it usually came on large size 
these diode used in power supply or voltage doubler circuit.

Small Signal Diode:
When dealing with high frequency and small current in mA, so this kind of diode is convenient
it has small size and enveloped with glass to protect it from contamination.

it characterized by low power consumption in mw
and widely used in radio and television application.

Light Emitting Diode (LED):
These diode isn't only allow current in one direction but also emit light .

it has high forward voltage rating compared to normal diode, also rating forward voltage depend on the color.

for example:V_F of red LED is around 2.2V and blue is 3.3V

some of these LED are invisible such as infrared LED which are commonly used in remote control application.

Photo Diode:

This type of diode consume light energy and convert it into current

sensing light in reverse bias operation is the main function of these diode

in addition of sensing , large area of this photo diode can generate electricity in that case it used as solar cell.

Shockley Diode and DIAC:

it's kind of power diode that supports hysteresis phenomena . you can see the whole topic here Thyristor | Shockley Diode and DIAC

Silicon Controlled Rectifier (SCR) and TRAIC:

it similar to Shockley diode with gate terminal added . you can see the whole topic here Thyristor | Silicon Controlled Rectifier (SCR) and TRIA

Transient Voltage Suppression Diode:

transient occur in circuit when a sudden change of voltage occur this transient may damage circuit component, this kind of diode can avoid that 

so it's kind of protection component.

this diode can provide high impedance in normal operation and doesn't affect the current flow of circuit but when sudden spike occur it has very fast response and starts to enter the avalanche breakdown state  providing  very low impedance and reduce voltage to normal. 

Zener Diode:

as mentioned before diode allow current in one direction but in case of zener diode it also allow the other direction.

in reverse bias there's a reference value of voltage called breakdown voltage as exceeding this value the diode conduct current.

there are many product of zener with different break down voltage. 

it used as over voltage protection and voltage regulation.

Schottky Diode:

It also called schottky barrier or hot carrier it formed by combination of semiconductor material and metal that's why this kind of diode has very low forward voltage rating reach 0.15 , high current rating , low power consumption and very fast switching action.

it can used as voltage clamping and high frequency rectifier application.