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Q: What are the advantanges and disadvantanges of jfet over bjt?
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What are the advantages and disadvantages of JFET over BJT?

An advantage of JFET is stable high current operation. A disadvantage of JFET is low capacitance. An advantage of BJT is constant voltage operation. A disadvantage of BJT is low thermal conductance.


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


What is the difference between jfet and mosfet?

1-BJT is bipolar while JFET is unipolar. 2-BJT has low input impedence while JFET has high input impedence. 3-JFET has low power discipation as compared to BJT. 4-JFET has low noise as compared to BJT. 5-BJT is current controlled while JFET is voltage controlled. 6-JFET is mostly used in digital circuits.


What are current controllable devices?

BJT is a example for current controll device. And JFET is a voltage controlled device.


Advantages of fet over bjt?

mainly i will tell ttwo advantages:- 1)in FET "thermal runaway" never occurs but in bjt it occurs easily...thermal runaway means overheating and damage of fet due to different biasing voltages.. 2) since FET is a unipolar device so only one carrier type is required here ,but bjt is a bipolar device .. 3) FET is smaller in size than BJT of same rating. i mean to say that at the place of 10 bjts we can use 90 FETs ..so area cosumption is less


Why fet is preferred over the bjt?

Disadvantage:Easy to damage when compared to BJT


What can transistors be?

either field effect (JFET, MOSFET) or junction (BJT) or point contact (usually considered obsolete)either small signal or high powereither electron majority carrier (N-channel FET, NPN BJT) or hole majority carrier (P-channel FET, PNP BJT)either linear (used in amplifier and oscillator circuits) or switching (used in digital logic circuits)etc.


Transistors can be either what or what?

either field effect (JFET, MOSFET) or junction (BJT) or point contact (usually considered obsolete)either small signal or high powereither electron majority carrier (N-channel FET, NPN BJT) or hole majority carrier (P-channel FET, PNP BJT)either linear (used in amplifier and oscillator circuits) or switching (used in digital logic circuits)etc.


How is a transistor used as a switch?

A transistor (bipolar junction transistor BJT) will only conduct in ONE DIRECTION. And the voltage drop is not Ohmic - it is *NOT* strictly related to current flow. If you're referring to a Field-Effect Transitor (JFET, IGFET, MOSFET, etc), then the device may be able to be used in a bidirectional circuit. But the question stated "transistor", which is understood to be a BJT.


How a transistor use as a switch?

A transistor (bipolar junction transistor BJT) will only conduct in ONE DIRECTION. And the voltage drop is not Ohmic - it is *NOT* strictly related to current flow. If you're referring to a Field-Effect Transitor (JFET, IGFET, MOSFET, etc), then the device may be able to be used in a bidirectional circuit. But the question stated "transistor", which is understood to be a BJT.


What does gm0 represent in a BJT amplifier circuit?

gm0 is not used in BJT amplifier circuits; it is used in JFET circuits. It is the transconductance at zero gate bias. Since the transconductance varies as the bias is varied, this gives a benchmark level at a given defined point, and other transconductances can be calculated from it as a function of the amount of negative bias on the gate. If it were linear it would be the same everywhere, but it is not.


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.