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

Explain extrinsic semiconductor, Explain Extrinsic Semiconductor. Extr...

Explain Extrinsic Semiconductor. Extrinsic Semiconductor: An intrinsic semiconductor is able to conduct some current even at room temperature but as this is not helpful for t

Inverter, single phase voltage source inverter complete circuit

single phase voltage source inverter complete circuit

Determine the hysteresis and eddy-current losses, Q. The total core loss fo...

Q. The total core loss for a specimen of magnetic sheet steel is found to be 1800 W at 60 Hz. When the supply frequency is increased to 90 Hz, while keeping the flux density consta

Thevenin theorem, advantages and disadvantages of thevenin theorem

advantages and disadvantages of thevenin theorem

Illustrate inverting operational amplifier, (a) Give the characteristics of...

(a) Give the characteristics of ideal OP-Amp? (b) Illustrate inverting operational amplifier with feedback. get the expression for voltage gain with feedback? Write short not

Explain the excess three codes - bcd to decimal conversion, Explain the Exc...

Explain the Excess three codes - BCD to Decimal Conversion The Excess-3 representation of a number is based on Binary Coded Decimal. It is formed by taking the number in Binary

Determine the active - reactive and apparent power, Determine the active - ...

Determine the active - reactive and apparent power: In the given circuit, determine the active, reactive and apparent power. Figure Solution  The inductive

what does quality factor mean, The Quality factor is also explained, as Q....

The Quality factor is also explained, as Q. So it is a number, which shows the lossness of a circuit. Higher the Q, the lower are the losses. The quality factor is calculated o

Show maximum differential input voltage of amplifier, Q. Show Maximum Diffe...

Q. Show Maximum Differential Input Voltage of amplifier? This is the maximum value of differential input voltage v p - v n that can be applied without damaging the op amp.

State the significance of lock signal in 8086, State the significance of LO...

State the significance of LOCK signal in 8086? If 8086 is working at maximum mode, there are multiprocessors are there. If the system bus is given to a processor then the LOCK

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