What type of diode to use

As the name suggests, these are made from semiconductor materials , primarily doped silicon. I—V current vs. Despite being nothing more than a simple two-pin semiconductor devices, diodes are vital to modern electronics.

Some of their most common applications include turning AC to DC , isolating signals from a supply, and mixing signals. At the same time, electrons flow in a single direction only from the negative side to the positive side. This is because electrons are negatively charged and are attracted to the positive end of a battery.

Diodes are extremely useful components and are widely used in modern technology. Perhaps the most widely known modern application for diodes is in LEDs. When both the electric fields are summed up, then the resultant electric field path is similar to that of the internal electric field path. This develops a thicker and enhanced resistive depletion region.

The depletion region experiences more sensitivity and thickness when the applied level of voltage is more and more. In addition, it is even more crucial to be aware of the V-I characteristics of the PN junction diode. This signifies that the potential barrier restricts the current flow.

Whereas when the diode operates in forwarding bias conditions, there will be a thinner potential barrier. In silicone type of diodes, when the voltage value is 0. In this, there will be a gradual increase in the current value and the resultant curve is non-linear where because the applied voltage level surmounts the potential barrier.

When the diode surmounts this potential barrier, the diode functions in normal condition, and the shape of the curve gradually gets sharp gets to linear shape with the rise of the voltage value. Where when the diode operates in reverse bias condition, there will be an increased potential barrier. As there will be the presence of minority charge carriers in the junction, this allows for the flow of reverse saturation current.

When there is an increased level of applied voltage, the minority charge carriers possess risen kinetic energy that shows an impact on the majority charge carriers.

At this stage, the diode breakdown happens and this might lead to the diode getting damaged. The Schottky diode has a lower forward voltage drop than ordinary Si PN-junction diodes.

At low currents, the voltage drop may be between 0. To attain this performance they are designed in a different way to compare with normal diodes having a metal to semiconductor contact. These diodes are extensively used in rectifier applications, clamping diodes, and also in RF applications. A step recovery diode is a type of microwave diode used to generate pulses at very HF high frequencies.

These diodes depend on the diode which has a very fast turn-off characteristic for their operation. The tunnel diode is used for microwave applications where its performance surpassed that of other devices of the day. In the electrical domain, tunneling signifies that it is the direct movement of electrons through the minimal width of the depletion region from the conduction band to the valency band. In the PN junction diode, the depletion region is developed because of both electrons and holes.

Because of these positive and negative charge carriers, the internal electrical field is developed in the depletion region. This creates a force in the opposite path of an external voltage. With the tunneling effect, when there is minimal forward voltage value, then the forward current value will be more. It can be functioned both in forward and reverse biased conditions. Because of the high level of doping , it can function in reverse biasing also.

With the decrement of barrier potential, the breakdown voltage in reverse direction also gets decreased and reaches nearly to zero. With this minimal reverse voltage, the diode may reach to breakdown condition. Because of this negative resistance region is formed.

A varactor diode is one sort of semiconductor microwave solid-state device and it is used in where the variable capacitance is chosen which can be accomplished by controlling voltage. These diodes are also called as variceal diodes. But, this diode is chosen for giving the preferred capacitance changes as they are different types of diodes. These diodes are precisely designed and enhanced such that they allow a high range of changes in capacitance. The Zener diode is used to provide a stable reference voltage.

As a result, it is used in vast amounts. It works under reverse bias condition and found that when a particular voltage is reached it breaks down. If the flow of current is limited by a resistor, it activates a stable voltage to be generated.

This type of diode is widely used to offer a reference voltage in power supplies. There exist various methods in the package of a Zener diode. They are discussed below. It is a type of P-N junction diode which operates on low voltage signals. Its junction area is very small.

It enables the small signal diode to have high switching speed with very fast recovery time. However, its limitations are low voltage and current parameters. Due to its high switching speed, these types of diodes are used in circuits with high frequencies.

A rectifier diode is a type of P-N junction diode, whose P-N junction area is very large. This results in high capacitance in reverse direction.

It has low switching speed. This is the most common and most used type of a diode. The Schottky diode, named after a German physicist Walter H. Schottky, is a type of diode which consists of a small junction between an N-type semiconductor and a metal. It has no P-N junction. The plus point of the Schottky diode is that it has very low forward voltage drop and fast switching. As there is no capacitive junction P-N junction , the Schottky diode switching speed is very fast.

The limitation of Schottky diode is that it has low reverse breakdown voltage and high reverse leakage current. Super barrier diodes SBR are also rectifier diodes but they have a low forward voltage drop just like a Schottky diode.

They have low reverse leakage current just like a normal P-N junction diode. SBR has a low forward voltage drop, less reverse leakage current and fast switching capability. The light emitting diode is also a type of P-N junction diode that emits light in the forward bias configuration.

LED is made up of a direct-band semiconductor. When the charge carriers electrons cross the barrier and recombine with electron holes on the other side, they emit photon particles light. While the color of the light depends on the energy gap of the semiconductor. LED converts electrical energy into light energy.

The photodiode is a type of P-N junction diode that converts the light energy into electrical current. Its operation is opposite to that of an LED. Every semiconductor diode is affected by optical charge carriers. It is why they are packaged in a light blocking material. In the photodiode, there is a special opening that allows the light to enter its sensitive part. When the light Photon particles strikes the PN junction, it creates an electron-hole pair. These electron and hole flow out as electrical current.

To increase its efficiency, a PIN junction diode is used. A photodiode is used in reverse bias and they can be used in solar cells. A laser diode is similar to LED because it converts electrical energy into light energy.

But unlike LED, Laser diode produces coherent light. The laser diode consists of a PIN junction, where electron and holes combine together in the intrinsic I region. Laser diodes are used in optical communication, laser pointer, CD drives and laser printer etc. Tunnel diode was invented by Leo Esaki in for which he received Nobel prize in , which is why it is also known as Esaki diode. A tunnel diode is a heavily doped P-N junction diode. It works on the principle of the tunneling effect.

Due to heavy doping concentration, the junction barrier becomes very thin. This allows the electron to easily escape through the barrier. This phenomenon is known as tunneling effect. The Tunnel diode has a region in its VI curve where the current decreases as the voltage increases. This region is known as the negative resistance region. The tunnel diode operates in this region in different applications such as an oscillator and a microwave amplifier.

The symbol with VI characteristic curve of tunnel diode is given below:. Zener diode is named after Clarence Malvin Zener who discovered the zener effect. It is a type of diode, which not only allows the flow of current in the forward direction but also in reverse direction. The Zener diode has heavier doping concentration than a normal P-N junction diode. Hence, it has a very thin depletion region. In forward bias, it operates as a simple P-N junction diode Rectifier.

In reverse bias, it blocks until the reverse voltage reaches breakdown. After that, it allows the current flow with a constant voltage drop. Zener reverse breakdown is caused due to two reason i. A Zener diode is mainly used in reverse bias configuration. It provides a stabilized voltage for protection of circuits from overvoltage.