What are the applications of a pn junction diode?

A tunnel diode or Esaki diode is a type of semiconductor that is capable of very fast operation, well into the microwave frequency region (up to 300 gigahertz (0.100 cm)), made possible by the use of the quantum mechanical effect called tunneling.

Depletion Region. When a p-n junction is formed, some of the free electrons in the n-region diffuse across the junction and combine with holes to form negative ions. In so doing they leave behind positive ions at the donor impurity sites.

Knee voltage is also known as “cut-in-voltage”. The minimum amount of voltage required for conducting the diode is known as “knee voltage” or “cut-in-voltage”. And also said as The forward voltage at which the current through PN junction starts increasing rapidly is known as knee voltage.

P-n junctions are formed by joining n-type and p-type semiconductor materials, as shown below. Since the n-type region has a high electron concentration and the p-type a high hole concentration, electrons diffuse from the n-type side to the p-type side.

n is the ideality factor, also known as the quality factor or sometimes emission coefficient. The equation is called the Shockley ideal diode equation when n, the ideality factor, is set equal to 1.

Full-wave rectification converts both polarities of the input waveform to pulsating DC (direct current), and yields a higher average output voltage. Two diodes and a center tapped transformer, or four diodes in a bridge configuration and any AC source (including a transformer without center tap), are needed.

A semiconductor material has an electrical conductivity value falling between that of a conductor – such as copper, gold etc. – and an insulator, such as glass. This process is known as doping and resulting semiconductors are known as doped or extrinsic semiconductors.

In a semiconductor P-N junction, forward bias occurs when the P-type material is positive with respect to the N-type material; in reverse bias, the P-type material is negative with respect to the N-type material. When two electrodes are at the same potential, they are said to be at zero bias.

In p-type semiconductors, holes are the majority carriers and electrons are the minority carriers. P-type semiconductors are created by doping an intrinsic semiconductor with acceptor impurities (or doping an n-type semiconductor). A common p-type dopant for silicon is boron.

Varactor diode applications. Varactor diodes are widely used within the RF design arena. They provide a method of varying he capacitance within a circuit by the application of a control voltage. Voltage controlled oscillators, VCOs: Voltage controlled oscillators are used for a variety of applications.

Zener diodes are widely used as voltage references and as shunt regulators to regulate the voltage across small circuits. When connected in parallel with a variable voltage source so that it is reverse biased, a Zener diode conducts when the voltage reaches the diode’s reverse breakdown voltage.

A diode conducts (offers 0 resistance ideally i.e., it acts as a short circuit) only when it is forward biased so there will be current flow in the circuit and it offers very high impedance ( it acts as a open circuit) when reverse biased so there will be no current flow. This way p-n junction diode work as a switch.

The first thing we want to do is look at diode characteristics.

Diode Characteristics. A diode is simply a PN junction, but its applications are extensive in electronic circuits.

Diode Elements.

Ideal Diodes.

Practical Diodes.

Practical Diode Forward Bias.

Reverse Bias.

Exceed Breakdown Voltage.

Current Versus Voltage.

The breakdown voltage of an insulator is the minimum voltage that causes a portion of an insulator to become electrically conductive. For diodes, the breakdown voltage is the minimum reverse voltage that makes the diode conduct appreciably in reverse.

Application: 1.)It is the process of rectifier as one of the part of DC Power Supplies. 4.)In cut-out circuits utilized for waveform era. PN junctions have been used as rectifiers in power supplies, detectors in RF,circuits, Zener diodes which are voltage regulators, clippers, LED’s, PIN diodes are RF switches.

junction diode (plural junction diodes) (physics) A semiconductor rectifying device in which the barrier between the two regions of opposite conductivity (n-type and p-type) type produces the rectification. All solar cells are junction diodes.

A diode (one way valve) is a PN junction with p-type on one side and n-type on the other. When a positive voltage is applied to the p-type side (forward bias), it shrinks and overcomes the depletion zone, causing the current to flow from the p-type to the n-type side.

An ideal diode is a diode that acts like a perfect conductor when voltage is applied forward biased and like a perfect insulator when voltage is applied reverse biased. So when positive voltage is applied across the anode to the cathode, the diode conducts forward current instantly.

Diodes were the first semiconductor electronic devices. The discovery of crystals’ rectifying abilities was made by German physicist Ferdinand Braun in 1874. The first semiconductor diodes, called cat’s whisker diodes were made of crystals of minerals such as galena.

Depletion region or depletion layer is a region in a P-N junction diode where no mobile charge carriers are present. Depletion layer acts like a barrier that opposes the flow of electrons from n-side and holes from p-side.