Why fet is called a voltage-controlled device, Electrical Engineering

Assignment Help:

Q. Why FET is called a voltage-controlled device? Why its input resistance is high?

In the case of a FET the output current ID is a function of the voltage VGS applied to the input circuit. Hence FET is known as a voltage controlled device. The equation that governs the working of a FET is called Shockley's equation given by,

ID = IDSS[1 - (VGS/VP) 2

where, ID is the drain current

IDSS is the maximum saturation current

VGS is the voltage applied between gate and source

VP is the pinch-off voltage

A FET requires virtually no input current and hence IG is always made zero. This gives an extremely high input resistance to FET. The range of its input impedance is at a level of 1 to several 100MWs.


Related Discussions:- Why fet is called a voltage-controlled device

Find the current, 1. A 1 μm long and 100 μm 2 cross-sectional area silicon...

1. A 1 μm long and 100 μm 2 cross-sectional area silicon bar is doped with 10 16 /cm 3 phosphorous. Use the graph below to: a. Find the current at 300°K with 10 V applie

Permanent magnets, Materials with 'hard' magnetic B/H characteristics often...

Materials with 'hard' magnetic B/H characteristics often show a strong residual magnetism. This makes them suitable for making permanent magnets. If the ring material were magnetis

Energy stored in a switched inductor, The increase in the current is buildi...

The increase in the current is building up the magnetic field surrounding the coil. Energy is stored in that field. Consider the energy supplied by the voltage source during the

Determine the bandwidth required for transmission, 1. A PCM system uses 8 b...

1. A PCM system uses 8 bits per sample and the analog signal is limited to 4.3 kHz. The PCM data is transmitted using (a) BFSK and (b) ASK. Determine the bandwidth required for tra

Determine collector - emitter voltage and base current, Q. A transistor is ...

Q. A transistor is connected in common emitter configuration collector supply voltage Vcc is 10 volts load resistance Rl is 800ohm,voltage drop across load resistance is 0.8v and c

Compare mosfet with jfet, Q. Compare MOSFET with  JFET? a. In enhanceme...

Q. Compare MOSFET with  JFET? a. In enhancement and depletion types of MOSFET,the transverse electric field induced across an insulating layer deposited on the semiconductor ma

What is absolute permittivity, Absolute permittivity (ε):  Permittivity ...

Absolute permittivity (ε):  Permittivity is a capacitance or ability to kept energy of a capacitor.  A force was also generated, called as electric force and the symbol. It d

Capacitive coupling, A Class, "A" Amplifier is needed with the following sp...

A Class, "A" Amplifier is needed with the following specification: Collector Current = 5mA Needed offset voltage across RE= 2V Lowest input Frequency = 50Hz Use a BC108

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