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Why ordinary transistor is known as bipolar junction transistor?
Wiki User
∙ 13y ago
Transistor is known as bipolar junction becoz it has 2 pole. Input is given to the 2 junction and output is taken from to junction
Wiki User
∙ 13y ago
Ian Batty
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What is the application of bipolar junction transister?
bipolar junction transistor is known as BJT in short form.they are made by cascading two P-N junction.we can not imagine any electronics circuit without Bjt.they have plenty of applications,one of the most important application is of switch.it can act as a switch.moreover it can act as a resistor.they can amplify weak signals into strong signals.in a chip which is used to run a computer or laptop there are millions of transistors cascaded in a chip which has size nearly of fingernail. you can find more information on youtubeBy-Nihar.N.Suryawanshi.
What are the various types of transistors?
TransistorsThe two main types of transistors are the bipolar junction transistor (BJT) and the field-effect transistor (FET). Bipolar Junction TransistorsBJTs can have two different polarities, NPN and PNP. An NPN BJT is one where a positively-doped (P-type) semiconductor is sandwiched between two negatively-doped (N-type) semiconductors. A PNP BJT is, obviously, one where an N-type semiconductor is sandwiched between two P-types. Both types of BJTs have an exponential dependence between the input voltage and the current output. For the record, I should state that a semiconductor is basically a material with conductance between that of an insulator and a conductor. Silicon and germanium are the two most well-known semiconductors. Also, doping just means the addition of impurities into a semiconducting material in order for it to either: increase its electron acceptance (P-type) or increase its electron conductance (N-type). Some specific types of BJTs:HBT - heterojunction bipolar transistor - These types of transistors are very similar to BJTs except that the two P-type semiconductors in the PNP polarity, or the two N-type semiconductors in the NPN polarity, are doped differently relative to each other. The reason for doing this, simply stated, is to make it more difficult for a transistor to operate in the reverse direction from which is was intended.Grown-junction transistor - This was the first type of BJT and is self-explanatory. The PN or NP junctions, depending on whether it's of NPN or PNP polarity, respectively, are grown onto a single, solid crystal of semiconductor material. Grown, in this case, means slowly attached, chemically.Alloy-junction transistor - Similar to a grown-junction transistor except the semiconducting material onto which the PN or NP junctions are grown is specifically germanium.MAT - micro-alloy transistor - An improved, speedier version of the alloy-junction transistor. The materials of the PN or NP junctions of a MAT are metal-semiconductor, as opposed to semiconductor-semiconductor.MADT - micro-alloy diffused transistor - An improved, speedier version of the MAT. The dopant material of a MADT is diffused (thinly spread) accross the entire germanium crystal prior to PN or NP growth, as opposed to a MAT where the doping material is only on the metallic side of the PN or NP junction.PADT - post-alloy diffused transistor - An improved, speedier version of the MADT. A thin, diffused dopant layer of germanium is grown onto the germanium crystal, as opposed to the entire germanium crystal being diffused, which allows the germanium crystal to be as thick as necessary for mechanical strength purposes. The PN or NP junctions are then grown onto this thin layer.Schottky transistor - These are alloy-junction transistors with a Schottky barrier between the metal-semiconductor junction. All metal-semiconductor junctions act sort of like capacitors with a voltage between the junctions. Often, you'd like to minimize this voltage in order to minimize the saturation (the amount of the germanium crystal) needed for the transistor to work. Minimizing the saturation effectively speeds up the transistor's performance, which is great for things like switches. Schottky barriers use various materials to do exactly this.Surface-barrier transistor - These are just like Schottky transistors except that both junctions are metal-semiconductor as opposed to only one.Drift-field transistor - The doping agent of these transistors is engineered to produce a specific electric field. This effectually reduces the electrons' transit time between the junctions of the transistor, thereby making it work faster.Avalanche transistor - These transistors can operate in the breakdown voltage region of a transistor's junctions. The breakdown voltage is simply the minimum voltage in which an insulator starts acting like a conductor. Thus, these transistors allow for higher currents to be applied to them than their normal counterparts.Darlington transistor - These are simply two BJTs connected together to further increase the gain of the current output.IGBT - insulated-gate bipolar transistor - These transistors combine the use of BJTs as switches with an isolated-gate FET (see below) as the input. IGBTs provide much more efficient and faster switching than regular BJTs and are thus some of the most common transistors found in modern appliances.Photo transistor - These transistors convert electromagnetic radiation in the form of visible light, UV-rays, or X-rays into current or voltage. As opposed to the normal PN junctions found in many transistors, photo transistors use PIN junctions. PIN junctions are similar to PN junctions except that they have an additional intrinsic semiconductor between the P-type and N-type semiconducting regions. This intrinsic semiconductor is a very lightly doped semiconductor which exists, at least for the purposes of photo transistors, to supply a region within the junction where a photon (a particle of electromagnetic radiation with a specific energy) can ionize (knock an electron out of via the photoelectric effect) an atom of this semiconducting material. Because of the electric field caused from the surrounding P-type and N-type semiconducting regions, this ionization causes the photoelectron to move toward one end of the junction, thereby producing what's known as a photocurrent, which is then amplified in the same manner as all other BJTs. I promise that the rest of my answer won't get more complicated than this.Field-Effect TransistorsFETs use electric fields to control only one-type of charge carrier, as opposed to BJTs which control both types. Now's as good a time as any to introduce the concept of electron holes. Intuitively, electrons carry negative charge and are thus referred to as negative charge carriers. Well, the absence of an electron where one used to be is called an electron hole. These holes act exactly as electrons do in transistors except that they carry positive charge, in the form of missing negative charge, and are thus called positive charge carriers. FETs are designed to control either positive or negative charge carriers, in the form of holes or electrons, but not both. The flow of positive or negative charge carriers occurs through what's called the channel of an FET. FET channels are created within the bulk material of the FET, which is usually silicon. If you find this idea more complicated than what I wrote about photo transistors, that's only because you haven't looked up the physics behind the photoelectric effect yet. Some specific types of FETs:CNTFET - carbon nanotube field-effect transistor - These FETs use carbon nanotubes instead of silicon as their channel material. Carbon nanotubes are needed as FETs continue to get smaller in size. They help reduce effects, such as quantum tunneling and overheating, which are beginning to become real problems in small, silicon-based FETs.JFET - junction gate field-effect transistor - This FET supplies a voltage accross the charge-carrying channel that can pinch it shut, effectively stopping the current through the channel.MESFET - metal semiconductor field-effect transistor - Similar to, but faster than, JFETs, MESFETs use a Schottky barrier (see above) instead of a PN junction.HEMT - high electron mobility transistor - The FET version of an HBT (see above). Faster than a MESFET, the charge-carrying channel is between two different materials instead of within a single, doped region. Also known as a heterostructure FET (HFET) or a modulation-doped FET (MODFET).MOSFET - metal-oxide-semiconductor field-effect transistor - This is the most basic, and most common, type of FET, analogous to the standard BJT (see above). Instead of pinching its charge-carrying channel shut as in a JFET, a MOSFET has an insulator attached to its input electrode which can be turned on or off depending on whether a voltage is supplied accross it. The channel can be N-type (nMOS) or P-type (pMOS), as explained above under the "bipolar junction transistors" heading.ITFET - inverted-T field-effect transistor - This is simply any type of FET that extends vertically out from the horizontal plane in a T-shape, hence the name.MuGFET - multiple gate field-effect transistor - A MOSFET where more than one input shares the bulk material of the FET. The idea is to use the same FET, thus the same sized object, for multiple things. This concept came about due to the ever shrinking sizes of transistors.MIGFET - multiple independent gate field-effect transistor - A MuGFET where the multiple inputs are independently controlled.Flexfet - A MIGFET with two inputs, one on a JFET and the other on a MOSFET. The JFET and MOSFET are then "stacked" on top of each other. Due to its design, the JFET and MOSFET are coupled to each other; i.e. the channel through one effects the channel through the other and vice versa.FinFET - A MuGFET where the charge-carrying channel is wrapped around a piece of silicon, called a fin. The reason for doing this is similar to that of a PADT (see above); i.e. mechanical strength.FREDFET - fast-recovery (or reverse) epitaxial diode field-effect transistor - A cute name for a transistor which is basically designed to quickly turn off when no more voltage is being supplied to it.TFT - thin-film transistor - An FET where the semiconducting material is placed via thin films over the bulk of the device. This is opposed to the bulk of the device being the semiconductor itself, as in most FETs. The bulk material used in TFTs is often glass. The reason being so that the transistors can work behind a clear display in applications like liquid crystal display (LCD) monitors.OFET - organic field-effect transistor - An FET with an organic polymer semiconductor as its channel. These are like TFTs except the bulk of the device is plastic, allowing for very cool, flexible LCD monitors.FGMOS - floating gate MOSFET - A MOSFET with a "floating gate" input; i.e. an electrically isolated input that can store charge, like a capacitor, to be used later. These are the transistors behind flash drives.ISFET - ion-sensitive field-effect transistor - An FET that changes its current depending on the ion concentration of a solution. The solution itself is used as the input electrode in an ISFET.EOSFET - electrolyte-oxide-semiconductor field-effect transistor - A MOSFET with the metal replaced by an electrolyte solution. EOSFETs are used to in neurochips to detect brain activity.DNAFET - Deoxyribonucleic acid (DNA) field-effect transistor - A MOSFET with its input electrode being a layer of immobilized, single-stranded DNA. The current through the MOSFET is modulated by the varying charge distributions that occur when complimentary DNA strands hybridize to the layer of single-stranded DNA on the input electrode. DNAFETs are used, not surprisingly, in DNA sequencing.My sources all stem from the link below which is also a great place to learn more about transistors.
How do you calculate the current gain of a transistor?
Bipolar transistor current gain is also called "Beta," or the h-parameter "hfe." beta = current_out / current_in The beta of a BJT is mostly determined by the thickness of the Base region, and by the excess doping in the Emitter relative to the Base. A thin Base and a heavily-doped Emitter leads to a high value for current gain. In a BJT, beta = Ic / Ib In a FET, beta is usually taken as infinity, since no current flows in or out of the gate. Beta is an impirical number. It means nothing unless the Ic is known or the load. It can have a beta from 1000 to 10 it all depends on the load.
How does a leveraged buyout differ from an ordinary buyout?
In an ordinary buyout, the buyer usually has most of the cash with which to complete the purchase. A leveraged buyout, also known as an LBO, involves the buyer in borrowing money to fund the purchase in the hope the purchased asset will more than fund the debt interest repayment.
What are the common feelings that empathic distress can lead to?
Empathetic distress can lead to argumentative behavior, and emotional pain. It can also cause issues and is known to be closely related to those having mental issues like Bipolar, or personality disorders.
What is common collector bipolar junction?
A circuit in which the input signal is applied to its base and the collector is earthed (grounded) is known as common collector configuration of BJT (BiPolar Junction Transistor)
Why is an ordinary transistor known as a bipolar transistor?
because once saturated it will conduct current both way raja TOQEER (Pakistan)
Is ujt is a uni polar transistor?
UJT is known as Uni Junction Transistor
How do NPN bipolar junction transistors turn on and off?
In order to bias a bipolar junction transistor on, you need to forward bias the base-emitter junction at the same time you forward bias the collector-emitter junction, and the ratio of collector current over base current must be somewhat less than hFe, the transistor's gain. This is known as saturated, or non-linear mode, operation. In practice, we drive the base much harder than the calculated required current, so as to minimize dependency on varying hFe's for various transistors.Turning the transistor off is a simple matter of eliminating the base current.In the case of the NPN transistor, the base and collector would need to be more positive than the emitter. In the case of the PNP, they would need to be more negative.
Why FET is called as a unipolar transistor?
The FET is a semiconductor device with the output current controlled by an electric field. Since the current is carried predominantly by one type of carriers, the FET is known as a unipolar transistor.
What is basic construction of JFET?
A Jfet stands for junction field effect transistor. It is a transistor also known for being the simpleist field effect transistor. The basic construction contains has three parts the P-type input the n-type input and a depletion layer.
What is the application of bipolar junction transister?
bipolar junction transistor is known as BJT in short form.they are made by cascading two P-N junction.we can not imagine any electronics circuit without Bjt.they have plenty of applications,one of the most important application is of switch.it can act as a switch.moreover it can act as a resistor.they can amplify weak signals into strong signals.in a chip which is used to run a computer or laptop there are millions of transistors cascaded in a chip which has size nearly of fingernail. you can find more information on youtubeBy-Nihar.N.Suryawanshi.
How must the two transistor junction be biased proper transistor amplifier operation?
A: Actually it is only one transistor required for amplification the other junction can be a diode. As current Begin to flow it causes a bias across one junction which is opposite biasing for the other, A good differential amplifier will have those junction virtually at the same point with a very good current source because any mismatched will cause and output without any input. It is called voltage offset on the other end if the feedback current is very small it will also produce an output voltage offset known as current offset or basically errors
What is bipolar ic?
ic made from bjt is known as bipolar ic
What is transistor and how can it operate and what are its types?
A transistor is a semiconductor device used to amplify & switch electronic signals. The name transistor comes from the 'trans' of transmitter and 'sister' of resistor. Transistors are used in a wide array of electronic equipment, ranging from pocket calculators and radios to industrial robots and communications satellites.There are two types of transistor viz:Primary type transistor-The primary type of transistor in use is known as a bipolar junction transistor, which consists of three layers of semi-conductor material, two of which have extra electrons, and one which has gaps in it. The two with extra electrons (N-Type) sandwich the one with gaps (P-Type). These bipolar transistor are divided into NPN and PNP types. All these primary type of transistor are shielded to protect from light source if it is not shielded from light then the light may be used to open or close the gate, in which case it is referred to as a phototransistor, functioning as a highly-sensitive photodiode.Secondary type transistor-The secondary type of transistor is known as a field-effect transistor, and consists either entire of N-Type semi-conductive material or P-Type semi-conductive material, with the current controlled by the amount of voltage applied to the transistor.General process of Transistor WorkingEach transistor has a store of electrical charge that remains there until it is turned on. In order to turn on a transistor, a small electrical charge needs to enter it via the base. When this happens, the electrical charge opens up the collector, and a more powerful charge leaves through the emitter. Electrical charge is measured in milliamps, and the typical transistor will multiply an electrical charge by one hundred times the number of milliamps it has. The electrical charge that is emitted by a transistor will then flow through a route designated by however the component it is attached to is designed. Complex electronics have many paths that electrical currents need to travel on, and therefore many transistors will be needed in order to constantly supply enough power to work the device.
What is unipolar junction transistor?
The bipolar junction transistor is a current operated device with three terminals, emitter, base, and collector. There are two varieties, NPN and PNP. In the NPN variety, if the base is more positive than the emitter and that junction is conducting (greater than typically 0.7 volts), then the current through that junction will control a larger current through the collector emitter junction, when the collecter is also more positive than the emitter and that junction is also conducting. In the PNP variety, the same thing applies, but reverse positive to negative. You can operate in linear mode, where the base current controls the collector current, or you can operate in saturated (switched) mode, where the base current is enough to pass any collector current. This is all dependent on gain, also known as hFe, or beta.
Can acupressure be a treatment for bipolar disorder?
It's not known to be an effective treatment for bipolar disorder.
