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

Connection of shunt capacitors - vantage points, Connection of Shunt Capaci...

Connection of Shunt Capacitors - Vantage Points An unloaded distribution line is capacitive in character and a fully loaded line has inherent inductive and resistive features

Three phase power measurement, what is the relationship between the inducta...

what is the relationship between the inductance, capacitance and resistance in the 2-wattmeter experiment?

Matlab simulation, Simulate and compare BER of QPSK system and 4-QAM system...

Simulate and compare BER of QPSK system and 4-QAM system without grey coding Eb/No=0.2.4.6.8.10

Explain significance of loss tangent of dielectric material, Explain the si...

Explain the significance of the loss tangent of a dielectric material. The loss tangent contains a very small value for free space. For solid materials there tan δ = 0.003, tha

Design the low-pass filter, Q. Design the low-pass filter shown in Figure (...

Q. Design the low-pass filter shown in Figure (by determining L) to have a half-power frequency of 10 kHz.

Equivalent circuit of a polyphase induction machine, Equivalent Circuit of ...

Equivalent Circuit of a Polyphase Induction Machine The inductionmachinemay be regarded as a generalized transformer inwhich energy is converted and electric power is transferr

Explain about zener diodes, Q. Explain about Zener Diodes? Most diodes ...

Q. Explain about Zener Diodes? Most diodes are not intended to be operated in the reverse breakdown region. Diodes designed expressly to operate in the breakdown region are cal

Hybrid parameters, Hybrid parameters (or) h - parameters:- If the ...

Hybrid parameters (or) h - parameters:- If the input current that is denoted as i 1 and output Voltage that is denoted as V 2 are takes as independent variables, input v

Discuss all the five software interrupt instructions, Discuss all the five ...

Discuss all the five software interrupt instructions. The INTEL family microprocessor consist of software interrupts INT, INT0, INT3 and BOUND and IRET. Out of all these five

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