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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 else can I help you with?
What is the difference between BJT and NPN transister?
A BJT (bipolar junction transistor) is a general term that includes both NPN and PNP transistors. An NPN transistor has a layer of P-type semiconductor sandwiched between two N-type layers, allowing current to flow from the collector to the emitter when a small current is applied to the base.
What is the difference between fet and ujt?
The structure of a UJT is quite similar to that of an N-channel JFET. The main difference is that P-type (gate) material surrounds the N-type (channel) material in case of JFET and the gate surface of the JFET is much larger than emitter junction of UJT.
Why bjt is bipolar?
BJT stands for bipolar junction transistor because it is composed of two types of semiconductors (P and N-type) rather than just one type like a unipolar transistor. This allows for both electron and hole current flow in the device, giving it its bipolar characteristic.
What is the relation between the path difference and phase difference?
The phase difference between two waves is directly proportional to the path difference between them. The phase difference is a measure of how much the wave has shifted along its oscillation cycle, while the path difference is a measure of the spatial separation between two points where the waves are evaluated.
The transfer characteristics of a JFET with external bias?
In a JFET with external bias, the transfer characteristics typically show how the output current (ID) varies with the input voltage (VG). By applying an external bias voltage between the gate and source terminals, the JFET operates in its active region, allowing for control over the output current. This biasing scheme enables fine-tuning of the JFET's operating point and can influence parameters like transconductance and overall performance.
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 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 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 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
How jfet works?
A Jfet works by applying voltage to the drain of the jfet. A jfet will then conduct across from drain to source.
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.
What is the difference between BJT and NPN transister?
A BJT (bipolar junction transistor) is a general term that includes both NPN and PNP transistors. An NPN transistor has a layer of P-type semiconductor sandwiched between two N-type layers, allowing current to flow from the collector to the emitter when a small current is applied to the base.
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.
Difference between de-mosfets e-mosfets and jfets?
The basic theory of operation is the same, but the device structure is different. With both a MOSFET and a JFET, a conductive channel is established between two terminals (the drain and the source). The structure of the gate terminal makes the difference between the two. In a MOSFET, the metal gate is separated from the channel by an insulator (the O in MOSFET means Oxide, the insulator). In a JFET the gate is a doped region essentially within the conductive channel.
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.
