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What is the venin and norton equivalent circuit comment?
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Why the n-jfet is operated with the negative voltage not the positive voltage?
In a JFET the only insulation between the gate and the channel is a reverse biased diode junction, if this junction becomes forward biased then the gate and channel are effectively shorted and the device no longer acts as a transistor (it will act as a forward biased diode instead). In the n-channel JFET, the gate is the P-side of this diode and the channel is the N-side of this diode. To keep this diode reverse biased (and the device operating as a transistor) therefor the gate MUST always be maintained at a voltage more negative than the most negative section of the channel.
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.
Does pinch off voltage in jfet depends on temperature?
absolutelly
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 do you calculate the current gain of a transistor JFET?
FETs don't have current gain as no current flows through the gate. The gain of a FET is a voltage gain and is called mu.
Why should a JFET be operated with only reverse bias on the gate?
If the gate-channel junction of a JFET was not reverse biased the JFET would just act as a forward biased diode across that junction and the gate would cease to have any control over the channel conductance. For the same reason in a MOSFET the substrate-source/channel/drain junction must remain reverse biased. The MOSFET could not act as a MOSFET.
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.
Why must the gate to source voltage of an n channel Jfet always be zero or negative?
to made reverse bias junction between gate to source
What are the applications of jfet?
• High Input Impedance Amplifier. • Low-Noise Amplifier. • Differential Amplifier. • Constant Current Source. • Analog Switch or Gate. • Voltage Controlled Resistor. • JFET as a Switch • JFET as a Chopper • JFET as a Current source • JFET as a Amplifier • JFET as a Buffer
Why is the input impedance of a jfet so high?
If you mean JFET, it is because the gate junction is reverse biased.
Why fet operated in reverse bias?
you want to keep the channel electrically isolated from the gate (jfet) or substrate (mosfet) so that it operates as a fet, don't you? if it was forward biased it would just be a diode with no field effect.
The primary control on drain current in a JFET is exerted by?
Gate reverse bias
Why the n-jfet is operated with the negative voltage not the positive voltage?
In a JFET the only insulation between the gate and the channel is a reverse biased diode junction, if this junction becomes forward biased then the gate and channel are effectively shorted and the device no longer acts as a transistor (it will act as a forward biased diode instead). In the n-channel JFET, the gate is the P-side of this diode and the channel is the N-side of this diode. To keep this diode reverse biased (and the device operating as a transistor) therefor the gate MUST always be maintained at a voltage more negative than the most negative section of the channel.
The voltage of a given common source JFET amplifier is depend on what?
amplification factor
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.
Does an N channel JFET require a positive or negative value for Vgs?
To create the depletion layer required for JFET operation the gate-source junction must be reverse biased.for N channel, the channel must be positive relative to the gate meaning Vgs must be negativefor P channel, the channel must be negative relative to the gate meaning Vgs must be positive
Does an n-channel JFET requires a positive or negative value for VGS?
To create the depletion layer required for JFET operation the gate-source junction must be reverse biased.for N channel, the channel must be positive relative to the gate meaning Vgs must be negativefor P channel, the channel must be negative relative to the gate meaning Vgs must be positive
