PIN Diode

PIN Diode

PIN DIODE :  The diode with a wide, undoped intrinsic semiconductor region between a p-type semiconductor and an n-type semiconductor region. The p-type and n-type regions are typically heavily doped because they are used for ohmic contacts. The wide intrinsic region is in contrast to an ordinary p–n diode.This is known as PIN diode CHARECTERISTICS OF PIN DIODE :  The PIN diode obeys the standard diode equation for low frequency signals. At higher frequencies, the diode looks like an almost perfect (very linear, even for large signals) resistor. There is a lot of stored charge in the intrinsic region. At low frequencies, the charge can be removed and the diode turns off. At higher frequencies, there is not enough time to remove the charge, so the diode never turns off. The PIN diode has a poor reverse recovery time. The high-frequency resistance is inversely proportional to the DC bias current through the diode. A PIN diode, suitably biased, therefore acts as a variable resistor. This...
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Photo diode

Photo diode

PHOTO DIODE : A semiconductor diode which converts the light into an electrical current is called "PHOTO DIODE". The current is generated when photons are absorbed in thephotodiode. A small amount of current is also produced when no light is present.            Photodiodes are similar to regular semiconductor diodes except that they may be either exposed or packaged with a window or optical fiber connection to allow light to reach the sensitive part of the device. Many diodes designed for use specifically as a photodiode use a PIN junction rather than a p–n junction, to increase the speed of response. A photodiode is designed to operate in reverse bias. OPERATION OF PHOTO DIODE :             A photodiode is a p–n junction or PIN structure. When a photon of sufficient energy strikes the diode, it creates an electron-hole pair. This mechanism is also known as the inner photoelectric effect. If the absorption occurs in the junction's depletion region,...
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Schottky diode

Schottky diode

Schottky diode : it is a semiconductor diode formed by the junction of a semiconductor with a metal. It has a low forward voltage drop and a very fast switching action. The cat's-whisker detectors used in the early days of wireless and metal rectifiers used in early power applications can be considered primitive Schottky diodes. It is also known as hot carrier diode. schottky diode is named after a German physicist "Walter H.Schottky" Construction :  A metal–semiconductor junction is formed between a metal and a semiconductor, creating a Schottky barrier. Typical metals used are molybdenum, platinum, chromium or tungsten, and certain silicides ,whereas the semiconductor would typically be n-type silicon. The metal side acts as the anode, and n-type semiconductor acts as the cathode of the diode. This Schottky barrier results in both very fast switching and low forward voltage drop. Applications : Voltage clamping Reverse current and discharge protection Switched-mode power supplies Sample-and-hold circuits Drawbacks : The most evident limitations of Schottky diodes are their...
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VARACTOR / TUNING DIODE

VARACTOR / TUNING DIODE

INTRODUCTION : Varactor diode, is a diode that has a variable capacitance which is a function of the voltage that is impressed on its terminals. Varactor diodes are operated reverse-biased, and therefore no current flows. However, since the thickness of the depletion zone varies with the applied bias voltage, the capacitance of the diode can be made to vary. Usually, the capacitance is inversely proportional to the depletion region thickness and the depletion region thickness is proportional to the square root of the applied voltage. Therefore, the capacitance is inversely proportional to the square root of the voltage applied to the diode. It is also known as tuning diode or Variable Capacitance diode or Varicap diode or Variable Reactance diode. In this too they are several types if varactor diodes or tuning diodes : There are several different kinds of tuning / varactor diodes. At Future Electronics we stock many of the most common types categorized by power dissipation, nominal diode capacitance, minimum...
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Tesla building ‘world’s biggest’ lithium-ion battery in Australia

Tesla building ‘world’s biggest’ lithium-ion battery in Australia

Australia is famous for the Big Banana, the Big Pineapple and the Big Prawn. Now, another "world's biggest" is coming Down Under, and it's going to be just as much of a tourist attraction if Elon Musk has his way. Tesla is teaming up with French-based renewable energy company Neoen to build the world's biggest lithium-ion battery in South Australia by the end of the year. Tesla CEO Elon Musk jetted into Australia this afternoon to make the announcement, saying the battery will be "three times more powerful than anything else on earth. "The world will look at it as an example... [of] a large-scale battery application for the grid that will really take a large amount of load," he said. "This is definitely the way of the future, and I think other states will be taking a closer look at this and seeing if it's applicable to their needs. And I suspect in most cases it is." The Premier of South Australia, Jay Weatherill, announced the...
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TUNNEL DIODE

TUNNEL DIODE

TUNNEL DIODE (Esaki diode) is a type of semiconductor that is capable of very fast operation, well into the microwave frequency region, made possible by the use of the quantum mechanical effect called tunneling. It was invented in August 1957 by Leo Esaki, Yuriko Kurose and Takashi Suzuki when they were working at Tokyo Tsushin Kogyo, now known as  Sony. In 1973 Esaki received the Nobel Prize in Physics, jointly with Brian Josephson, for discovering the electron tunneling effect used in these diodes. Robert Noyce independently came up with the idea of a tunnel diode while working for William Shockley, but was discouraged from pursuing it. These diodes have a heavily doped p–n junction that is about 10 nm (100 Å) wide. The heavy doping results in a broken band gap, where conduction band electron states on the n-side are more or less aligned with valence band hole states on the p-side. Tunnel diodes were first manufactured by Sony in 1957 followed by General Electric and other...
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P-N Junction diode

P-N Junction diode

P-N junction diode : If a p-type semiconductor is combined with N-type semiconductor a junction is formed with two electrodes this is called " P-N junction diode". Symbol : Formation of depletion region at the function :   If P-N junction diode is formed , some of the holes in p-type and some of the electrons in N-type are diffuse towards each other and recombine. Due to this , narrow region is formed on either side of the junction is called " depletion region ". This region creates an electric field  and causes a potential is called " barrier potential ". This potential barrier steps further diffusion of electrons and holes .   Variation of depletion region : Forward bias : In forward bias , positive terminal of battery is connected to P-type and negative terminal is connected to N-type . Due to this , the holes and electrons are repelled and moved towards the junction . As a result , the width of deletion region decreases...
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Zener Diode – The basic building blocks of electrical circuits

Zener Diode – The basic building blocks of electrical circuits

Zener Diode : A properly doped P-N junction diode has sharp break down voltage , when operated in reverse bias is called "Zener Diode". ­  SYMBOL :   INVENTED BY :  The device was named after Clarence Melvin Zener, who discovered the Zener effect. Zener reverse breakdown is due to electron quantum tunnelling caused by a high strength electric field. USES  :    Zener Diode is used to generate low power stabilized supply rails from a higher voltage and to provide reference voltages for circuits, especially stabilized power supplies.They are also used to protect circuits from over-voltage, especially electrostatic discharge (ESD).Zener diodes are widely used in electronic equipment of all kinds and are one of the basic building blocks of electronic circuits. ZENER DIODE AS VOLTAGE REGULATOR :      " The device constant output voltage even if input voltage & load current changes is called VOLTAGE REGULATOR "  ...
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