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Because the operation of the transistor is determined by the current at the base. the principle equations of BJT operation are:
Ic = h*Ib ,and
Ie=Ib+Ic
thus device operation is controlled by the input current.
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What are the example current controlled device?
Bipolar junction transistor(BJT)
Is BJT is a current control device or voltage control device?
transistor is a current controlled device. as the current flows through the base of the transistor , it works like a close switch.
Why BJT is called bipolar device and FET an unipolar device?
FETs can be called UNIPOLAR devices because the charge carriers that carry the current through the device are all of the same type i.e. either holes or electrons, but not both. This distinguishes FETs from the bipolar devices in which both holes and electrons are responsible for current flow in any one device.
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.
Is IGBT the bipolar device?
IGBT and BJT are bipolar devices as the name suggest. Meaning of bipolar device both electrons and holes leads to current unlike FET where either electron or hole causes current.
What are the example current controlled device?
Bipolar junction transistor(BJT)
What is bjt and jfet?
BJT is Bipolar junction transistor FET is Field effect Transistor It is a current controlled device It is voltage controlled device
Why FET called current controlled device?
BJT is a current controlled device because its output current is dependent upon the current in the base while for FET it is controlled by the voltage at the gate terminal of the transistor. BJT is a current controlled device because its base current is not zero while for a FET the gate current is zero
What are current controllable devices?
BJT is a example for current controll device. And JFET is a voltage controlled device.
Difference between bjt and ujt?
UJT is the voltage controlled device.in which only one mejority carriers are responsible for current flowing. UJT is one junction transistor and it is three terminal emitter and two base. BJT is the current controlled device. in which both mejority and minority carrier are responsiblefor current flowing. this type of transistor consists of two junction and three terminal these are : emitter , base , collector.
Is BJT is a current control device or voltage control device?
transistor is a current controlled device. as the current flows through the base of the transistor , it works like a close switch.
What do you mean by a current controlled device?
It is modeled as a 2-port "black box", where the input terminals accept a current (and are modeled by 'zero' resistance to that current), and the output is a function of the input current. the output may be a voltage or current (or other varying physical parameter, such as resistance). A bipolar transistor is well modeled as a current controlled device. The collector (output) current is a function of the base current: Ic = Beta * Ib. The hybrid-pi model changes that from a current controlled device to a voltage controlled device: Ic = F(Vbe), but the BJT transistor is still basically a current controlled device.
What is current controlled current sources?
A unidirectional current controller device is a type of electrical on/off switch. In order for an item to work that is plugged into a particular outlet, the switch must be in the on position. It is like having lamps plugged into outlets that are controlled by only one switch.
What is the difference between jfet and bjt?
FET's (field effect transistors) are unipolar devices because unlike BJT's that use both electron and hole current, they operate only with one type of charge carrier. BJT is a current-controlled device; that is the base current controls the amount of collector current. FET is a voltage-controlled device, where voltave between two of the terminals (gate and source) controls the current through the device. BJT's have a low input impedance ( ~1k -3k ohms), while FET's have a very high input impedance (~10^11 ohms). Consequently FET's have a lower power consumption. BJT's produce more noise than FET's . FET's have a slower switching speed . BJT's are subject to thermal runway while FET's are immune to this problem. BJT's have a higher cutoff frequencey and a higher maximum current then FET's. FET's are easy to fabricate in large scale and have higher element density the BJT's.
What is FET?
FET is abbreviation of Field Effect Transistor. This is a transistor in which current is controlled by voltage only and no current is drawn. It is a high input impedence device and is used in computers, telecommunication and control circuits. This transistor is better in certain parameters as compared to BJT, that is Bipolar Junction Transistor.
Why is transistor called a current controlled device?
for a BJT to amplify we give input signalif suppose we use BJT in CE configuration input is given at Emitter-Base junction and output is taken at Collector base junctionthe input voltage increases or decreases the forward bias of the E-B junction affecting a change in the base current and we know that collector current is a function of base current collector current also variesso by selectively changing the base current we can effectively change the collector current
How is mosfet different from bjt?
BJT(Bipolar junction Transistor)-It is bipolar device -meaning both electron and holes are responsible for conduction.-It is mainly used for amplification and switching purposes.-It is current controlled device.MOSFET(Metal Oxide Semiconductor Field Effect Transistor)-It is unipolar device -meaning only one of the charge carriers is responsible for conduction.-It has very high input resistance.Due to this reason it is used in initial stage of Operational amplifier.-It is voltage controlled device.
