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The mobility of N type charge current carriers is more than two times greater than the mobility of P type charge carriers . Resulting in faster transistor operating speed .
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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
Difference between UJT and FET?
the differences between UJT and FET are :- 1. structural :- a. there is only one p-channel in the UJT where as two in JFET b. the p-channel of UJT is more highly doped when compared to p-channel in JFET 2. functional :- UJT always works in forward biased condition (gate is forward biased) where as JFET always work in rverse bias condition (gate is reverse biased)
Explain the operation of jfet with any time?
JFET Construction and OperationA schematic representation of an n channel JFET is shown in Figure 118. An n-type channel is formed between two p-type layers which are connected to the gate. Majority carrier electrons flow from the source and exit the drain, forming the drain current. The pn junction is reverse biased during normal operation, and this widens the depletion layers which extend into the n channel only (since the doping of the pregions is much larger than that of the n channel). As the depletion layers widen, the channel narrows, restricting current flow. Figure 118: n-channel JFET structure.When , there is little voltage drop along the length of the channel, and the depletion regions are parallel, Figure 119. As vGS is increased negatively, they eventually touch reducing iD to zero. The value of vGSat which this occurs is called the pinch-off voltage, Vp (or vGS(off)).Figure: n-channel JFET structure for showing parallel depletion regions.When , there is a voltage drop along the length of the channel, and the depletion regions are no longer parallel, but are closer together towards the drain, Figure 120. As vDS is increased, they will touch (pinch-off) towards the drain, and the drain current iD can increase no longer. At the threshold of pinch-off, vGS-vDS=Vp. As vDS is further increased, iD remains constant, and the JFET is in its current saturationregion, the normal mode of operation. (This constant current region is a characteristic feature of any transistor, FET or BJT.) The channel shape remains unchanged, with a small region of touch near the drain, and further increases in vDS occurs across this small region.Figure: n-channel JFET structure for showing non-parallel depletion regions.JFETS are high input impedance devices, and so (due to the reverse bias pn junctions).
What are the characteristics of bipolar junction transistor?
A Bipolar Junction Transistor(a.k.a. a BJT or BipolarTransistor) is an activesemiconductor deviceformed by twoP-N junctionswhose function is amplification of an electriccurrent.
What are the classifications of MOSFET?
MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor, It is broadly Classified into Depletion type MOSFETS and Enhancement type MOSFETS. Depletion type MOSFETS are further classified into P-Channel and N-Channel Depletion type MOSFET, Similarly Enhancement type MOSFETS are further classified into P-Channel and N-Channel Enhancement type MOSFET.
What are the distinguishing features of an n-channel JFET from a p-channel JFET?
diff. that in n channel & p channel two p type slab in fabricated n type semiconductor & vice -versa
What is semiconductor triode?
It can be either a Bipolar Junction Transistor (NPN or PNP) or a Field Effect Transistor (N channel JFET, P channel JFET, N channel MOSFET, or P channel MOSFET).
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.
How many junctions does a Field Effect transistor have?
1
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
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.
Difference between UJT and FET?
the differences between UJT and FET are :- 1. structural :- a. there is only one p-channel in the UJT where as two in JFET b. the p-channel of UJT is more highly doped when compared to p-channel in JFET 2. functional :- UJT always works in forward biased condition (gate is forward biased) where as JFET always work in rverse bias condition (gate is reverse biased)
Explain the operation of jfet with any time?
JFET Construction and OperationA schematic representation of an n channel JFET is shown in Figure 118. An n-type channel is formed between two p-type layers which are connected to the gate. Majority carrier electrons flow from the source and exit the drain, forming the drain current. The pn junction is reverse biased during normal operation, and this widens the depletion layers which extend into the n channel only (since the doping of the pregions is much larger than that of the n channel). As the depletion layers widen, the channel narrows, restricting current flow. Figure 118: n-channel JFET structure.When , there is little voltage drop along the length of the channel, and the depletion regions are parallel, Figure 119. As vGS is increased negatively, they eventually touch reducing iD to zero. The value of vGSat which this occurs is called the pinch-off voltage, Vp (or vGS(off)).Figure: n-channel JFET structure for showing parallel depletion regions.When , there is a voltage drop along the length of the channel, and the depletion regions are no longer parallel, but are closer together towards the drain, Figure 120. As vDS is increased, they will touch (pinch-off) towards the drain, and the drain current iD can increase no longer. At the threshold of pinch-off, vGS-vDS=Vp. As vDS is further increased, iD remains constant, and the JFET is in its current saturationregion, the normal mode of operation. (This constant current region is a characteristic feature of any transistor, FET or BJT.) The channel shape remains unchanged, with a small region of touch near the drain, and further increases in vDS occurs across this small region.Figure: n-channel JFET structure for showing non-parallel depletion regions.JFETS are high input impedance devices, and so (due to the reverse bias pn junctions).
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 are the characteristics of bipolar junction transistor?
A Bipolar Junction Transistor(a.k.a. a BJT or BipolarTransistor) is an activesemiconductor deviceformed by twoP-N junctionswhose function is amplification of an electriccurrent.
Why junction field effect transistor is called as unipolar devices?
Field Effect Transistors (both JFET & MOSFET) are unipolar because they use only one type of current carrier (electrons in N-channel or holes in P-channel), unlike bipolar transistors (both junction & the obsolete point contact) which always use both types of current carriers.
