Diode

Blog Number:-004
Hello Everybody,
Well, I wish You all will be fine and healthy. And I also wish that my blogs might be useful to all my Readers.
So. after talking about basic Electrical Components, Let us now discuss about basic Electronics Components. and today we will discuss about Diode.
                       Before going for Diode directly, let us discuss Semiconductor and Semiconductor Devices first.

Semiconductor:-

A semiconductor material has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Their resistance decreases as their temperature increases.Their conducting properties may be altered in useful ways by the deliberate, controlled introduction of impurities ("doping") into the crystal structure. Where two differently-doped regions exist in the same crystal, a semiconductor junction is created.

     Semiconductor Materials-

By far, silicon (Si) is the most widely used material in semiconductor devices. Its combination of low raw material cost, relatively simple processing, and a useful temperature range makes it currently the best compromise among the various competing materials.

Germanium (Ge) was a widely used early semiconductor material but its thermal sensitivity makes it less useful than silicon.

Gallium arsenide (GaAs) is also widely used in high-speed devices.

Silicon carbide (SiC) has found some application as the raw material for blue light-emitting diodes (LEDs) and is being investigated for use in semiconductor devices that could withstand very high operating temperatures

Various indium compounds (indium arsenide, indium antimonide, and indium phosphide) are also being used in LEDs and solid state laser diodes. Selenium sulfide is being studied in the manufacture of photovoltaic solar cells.

Semiconductor materials are useful because their behavior can be easily manipulated by the addition of impurities, known as doping. Semiconductor conductivity can be controlled by the introduction of an electric or magnetic field, by exposure to light or heat

Now. we will discuss about Semiconductor Devices.

Semiconductor devices:-

Semiconductor devices are electronic components that exploit the electronic properties of semiconductor materials, principally silicon, germanium, and gallium arsenide, as well as organic semiconductors. Semiconductor devices have replaced thermionic devices (vacuum tubes) in most applications. They use electronic conduction in the solid state as opposed to the gaseous state or thermionic emission in a high vacuum.

Semiconductor devices are manufactured both as single discrete devices and as integrated circuits (ICs)

List of common semiconductor devices

 Two-terminal devices:

• Diode (rectifier diode)
• Light-emitting diode (LED)
• Solar cell
• Zener diode and Many more

Three-terminal devices:

• Bipolar transistor
• Insulated-gate bipolar transistor (IGBT)
• Silicon-controlled rectifier
• Thyristor

Four-terminal devices:

• Hall effect sensor (magnetic field sensor)

Now, We will discuss about diode.

Diode:-

    Introduction-

Diode

          In electronics, a diode is a two-terminal electronic component that conducts primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance to the current in one direction, and high (ideally infinite) resistance in the other. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals.  Semiconductor diodes were the first semiconductor electronic devices.

            The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking current in the opposite direction (the reverse direction). Thus, the diode can be viewed as an electronic version of a check valve. This unidirectional behavior is called rectification, and is used to convert alternating current (AC) to direct current (DC).

             Semiconductor diodes begin conducting electricity only if a certain threshold voltage is present in the forward direction (a state in which the diode is said to be forward-biased). The voltage drop across a forward-biased diode varies only a little with the current, and is a function of temperature.

    Electronic symbols-

There are two types of connection in Diode:-

1) Forward Biased

2) Reversed Biased

1) Forward Biased- When positive terminal of power source is connected to anode and negative terminal of same power source is connected to cathode, then this  particular connection is called Forward Biased.

2) Reverse Biased- When positive terminal of power source is connected to cathode and negative terminal of same power source is connected to anode, then this  particular connection is called Reverse Biased. 

In Forward Biased, the Diode behaves like a short circuit which have very less resistance(ideally zero).

In Reverse Biased, the Diode behaves like an open circuit which have very high resistance(ideally infinite).

So, We can say that a Diode has switching characteristics and can behave as a switch.