Different types of diodes and their properties:
Two terminal Junction Diodes: A p-n junction diode is a solid-state device that has two terminals. Depending on impurity distribution, device geometry, and biasing condition, a junction diode can perform various functions. There are a very large variety of diodes with voltage ratings from <1V to >2000V and current ratings from <1mA to >5000A. P-N junctions can generate and detect light and convert optical radiation into electrical energy.
Two terminal Junction Diodes: A p-n junction diode is a solid-state device that has two terminals. Depending on impurity distribution, device geometry, and biasing condition, a junction diode can perform various functions. There are a very large variety of diodes with voltage ratings from <1V to >2000V and current ratings from <1mA to >5000A. P-N junctions can generate and detect light and convert optical radiation into electrical energy.
Rectifier: This type of p-n junction diode is specifically designed to rectify an alternating
current i.e. to give a low resistance to current flow in one direction and a very high
resistance in the other direction. Such diodes are generally designed for use as power-
rectifying devices that operate at frequencies from 50–50K Hz. The majority of rectifiers
have power-dissipation capabilities from 0.1 to 10 watts and a reverse breakdown voltage
from 50 to >5000 V. (A high-voltage rectifier is made from two or more p-n junctions
connected in series.)
Zener diode: This voltage regulator is a p-n junction diode that has a precisely tailored impurity distribution to provide a well-defined breakdown voltage. It can be designed to have a breakdown voltage over a wide range from 0.1 volt to thousands of volts. The Zener diode is operated in the reverse direction to serve as a constant voltage source, as a reference voltage for a regulated power supply, and as a protective device against voltage and current transients.
Varactor diode: The varactor (variable reactor) is a device whose reactance can be varied in a controlled manner with a bias voltage. It is a p-n junction with a special impurity profile, and its capacitance variation is very sensitive to reverse-biased voltage. Varactors are widely used in parametric amplification, harmonic generation, mixing, detection, and voltage-variable tuning applications.
Tunnel diode: A tunnel diode consists of a single p-n junction in which both the p and n sides are heavily doped with impurities. The depletion layer is very narrow (~100 A). Under forward bias, electrons can tunnel or pass directly through its junction, producing
Zener diode: This voltage regulator is a p-n junction diode that has a precisely tailored impurity distribution to provide a well-defined breakdown voltage. It can be designed to have a breakdown voltage over a wide range from 0.1 volt to thousands of volts. The Zener diode is operated in the reverse direction to serve as a constant voltage source, as a reference voltage for a regulated power supply, and as a protective device against voltage and current transients.
Varactor diode: The varactor (variable reactor) is a device whose reactance can be varied in a controlled manner with a bias voltage. It is a p-n junction with a special impurity profile, and its capacitance variation is very sensitive to reverse-biased voltage. Varactors are widely used in parametric amplification, harmonic generation, mixing, detection, and voltage-variable tuning applications.
Tunnel diode: A tunnel diode consists of a single p-n junction in which both the p and n sides are heavily doped with impurities. The depletion layer is very narrow (~100 A). Under forward bias, electrons can tunnel or pass directly through its junction, producing
a negative resistance effect (its current decreases with increasing voltage). Because of
its short tunneling time across the junction and its inherent low noise, the tunnel diode is
used in special low-power microwave applications, such as a local oscillator and a
frequency-locking circuit.
Schottky diode: When a metal-semiconductor contact (e.g., aluminum layer in intimate
contact with an n-type silicon) exhibits rectifying behavior it is called Schottky diode. It is
electrically similar to a p-n junction, though the current flow in the diode is due primarily
to majority carriers having an inherently fast response. It is often used for high-frequency,
low-noise mixer and in switching circuits. Metal-semiconductor contacts can also be non-
rectifying and then it has negligible resistance to flow of current in both directions. Such
a contact is called ohmic contact. All semiconductor devices as well as integrated circuits
need ohmic contacts to make connections to other devices in an electronic system.
The p-i-n diode
A p–i–n diode is a p–n junction which sandwiches an intrinsic layer (i–region) between its p and n doped layers. The p–i–n diode has found wide application in microwave circuits. It can be used as a microwave switch with essentially constant depletion–layer capacitance (equal to that of a parallel–plate capacitor having a distance between the plates equal to the thickness of i–region) and high power-handling capability.
The p-i-n diode
A p–i–n diode is a p–n junction which sandwiches an intrinsic layer (i–region) between its p and n doped layers. The p–i–n diode has found wide application in microwave circuits. It can be used as a microwave switch with essentially constant depletion–layer capacitance (equal to that of a parallel–plate capacitor having a distance between the plates equal to the thickness of i–region) and high power-handling capability.
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