Why fet is a voltage sensitive device, Electrical Engineering

Assignment Help:

Q. Why FET is a voltage sensitive device explain from the drain characteristics?

The JFET consists of a thin layer of n-type material with two ohmic contacts,the source S and the drain D ,along with two rectifying contacts ,called the gates G .If a positive voltage is placed between drain and source,electrons will flow from source to drain .This conducting path between the source and the drain is called a channel.

Consider holding the drain source voltage fixed and varying the gate-source voltage .As the gate-source voltage is made negative ,the gate channel  pn junction is   reverse biased ,increasing the depletion red\gion between the gate and source .This decreases the channel width ,increasing the channel resistance.if the drain-source voltage  VDS is kept constant   ,the current IDS  decreases .when the gate-source voltage  is  made positive,the depletion region decreases until,for large positive gate-source voltages ,the channel opens .then the pn- junction  between gate and channel  becomes  forward biased and current flows from the gate to the source current Summarizing we find that varying the gate voltage varies the channel width ,and hence the channel resistance  .This  inturn  varies the current from drain to source,IDS .We see that it is the gate-source voltage variation which varies IDS ; thus the FET is a voltage sensitive device ,compared with the junction transistor , which is a current sensitive device.


Related Discussions:- Why fet is a voltage sensitive device

Error in simulink, dear sir, when i am going to simulate my model in matlab...

dear sir, when i am going to simulate my model in matlab i am getting the following error : the derived input for the integrator is inf or nan at time xxxxx. try to reduce the step

Merits and demerits of fixed bias with emitter resistor, Merits: The ci...

Merits: The circuit has the trend to stabilize operating point against changes in temperature and β-value. Demerits: In this type of circuit, to keep I C  independent o

Impedance heating system, Under what circumstances is individual circuit pr...

Under what circumstances is individual circuit protection for a lighting and applications panel board not required? What is the purpose of guarding runway contact conductors and

Determine the speed at which the machine runs as a motor, A 100-kW, dc shun...

A 100-kW, dc shunt generator, connected to a 220-V main, is belt-driven at 300 r/min, when the belt suddenly breaks and the machine continues to run as a motor, taking 10 kW from t

Subtract contents of memory and borrow from accumulator, Subtract Contents ...

Subtract Contents of Memory and Borrow from Accumulator The contents of the  memory  pointed  by the HL register  pair  and the borrow  flag are subtracted from the  contents

Distribution loss reduction and efficiency improvement, Distribution Loss R...

Distribution Loss Reduction and Efficiency Improvement You are well aware of the fact in which all energy supplied to a distribution utility does not reach the end consumers.

Electric Optic Device, Transmission Through a LiNb0 3 Plate Examine the tr...

Transmission Through a LiNb0 3 Plate Examine the transmission of an unpolarized He-Ne laser beam (?o= 633 nm) normally incident on a LiNb0 3 plate (ne = 2.29, no = 2.20) of thickn

Scr, what is finger voltage?

what is finger voltage?

What is the pipelining, A method used in advanced microprocessors where the...

A method used in advanced microprocessors where the microprocessor begins implementing a second instruction before the first has been done. That is, various instructions are in the

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd