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

Chemical vapour deposition, Explain chemical vapour deposition method for t...

Explain chemical vapour deposition method for the preparation of nanomaterial and its properties

How do you modify the direction of rotation of a d.c. motor, Q. How do you ...

Q. How do you modify the direction of rotation of a D.C. motor? Ans: The direction of rotation of DC motor will be changed either by changing the field winding connections o

Explain cascading of multiple pics 8259, Explain cascading of multiple PICS...

Explain cascading of multiple PICS 8259.  The 8259A adds 8 vectored priority encoded interrupts to the microprocessor. It can be expanded to 64 interrupt requests by using one

Frequency response of amplifiers, Q. Frequency response of amplifiers? ...

Q. Frequency response of amplifiers? All amplifiers exhibit variations of performance as the signal frequency is changed. The frequency response of an amplifier may be defined

Draw a block diagramfor a 2-to-4 decoder, Q. Draw a block diagramfor a 2-to...

Q. Draw a block diagramfor a 2-to-4 decoder. Obtain the truth table, and develop a logic diagram.

Ripple voltage amplitude, a) What is meant by Ripple Voltage?  Measure the ...

a) What is meant by Ripple Voltage?  Measure the Ripple Voltage Amplitude, Frequency and DC Offset b) Describe how Ripple Voltage could be decreased.

Merits and demerits of voltage divider bias, Merits and Demerits of Voltage...

Merits and Demerits of Voltage divider bias: Merits: 1. Not like the above circuits, only one dc supply is essential. 2. Operating point is approximately independent o

Transistor, describe the compensation technique for both Vbe and Icbo

describe the compensation technique for both Vbe and Icbo

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