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

Digital Electronics, Design a MOD-6 synchronous counter using J-K Flip-Flop...

Design a MOD-6 synchronous counter using J-K Flip-Flops.

Magnetic circuits with air gaps, The creation of a magnetic field in a ring...

The creation of a magnetic field in a ring may need to be accessed by means of an air gap. This is typically used to apply the magnetic field to a current carrying conductor to pro

What is a positive clipper and explain its working, Q. What is a positive c...

Q. What is a positive clipper? Explain its action with the help of a circuit. A positive clipper is the circuit which is used to cut off the positive half cycle. The circuit wi

Explain graphics adapters, Explain graphics adapters. Video card conve...

Explain graphics adapters. Video card converts digital output by the computer in an analog video signal and sends the signal by a cable to the monitor also termed as a graphic

Determine the percentage ripple voltage, Problem (a) Figure gives the ...

Problem (a) Figure gives the basic circuit of the diode limiter. Assuming that the diodes are ideal sketch and annotate the waveforms of the input voltage vi(t) and the load

Series connected motor, In this case, the armature is connected in series w...

In this case, the armature is connected in series with the field coils. Thus I a   = I f = I         NB. At starting, the back emf is zero (because the m

project, I want to make project plz help me n gove me idea about actually ...

I want to make project plz help me n gove me idea about actually its my first year in electrical engineering thts why Ineed help hpfully you will reply soon

Determine the low-pass filter and amplitude spectra, Q. Let a square-wave v...

Q. Let a square-wave voltage source having an amplitude of 5V, a frequency of 1 kHz, a pulse width of 0.5 ms, and an internal source resistance of 50  be applied to a resistive lo

Personal and corporate income tax rate, Ginny Jones currently works as the ...

Ginny Jones currently works as the VP-Product Strategy for a well-established enterprise software company. She and her friend, Tom Robinson, currently CFO at a competing firm (and

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