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what is MOSFET ?

1 Answer

•MOSFET is a type of Field Effect Transistor (FET).

•It is a voltage controlled transistor.

•MOSFET have very high input impedance.

•It can be use with very low current circuits.

•It is very fast switching device.

•It is also use for amplifying signals.

•It is useful in low power high frequency converter applications.

•It is use in memory and ICs and processors and various faster switching application.

•It basically consists of 4 terminals out of which two terminals are connected to each other i.e. drain and body.

•Its operation based on flow of majority charged carrier only.

•It is a unipolar device.

•It form a parallel plate capacitor with gate oxide layer.

•It have problem of electrostatics discharge.

•The gate draws a very small leakage current in the order of Nano ampere.

•There are two types of MOSFET one is enhancement mode and second is depletion mode.

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Related questions

Description :

Answer : MOSFETs are of two types namely  1) enhancement type MOSFET  or  E-MOSFET 2) depletion type MOSFET  or  D-MOSFET

Description : what are the uses of MOSFET ?

Answer : Choppers and inverters and where high switching frequency is required.

Description :

Answer : Yes IGBT is costlier than BJT and MOSFET.

Description :

Answer : No MOSFET do not have a second breakdown problem.

Description :

Answer : MOSFET  are voltage controlled devices.

Description :

Answer : MOSFET have high current losses due to High on state resistance. Hence MOSFET is used for low power applications.

Description :

Answer : Because of positive temperature coefficient of mosfet the paralleling of mosfet is easier.

Description :

Answer : Yes MOSFET can operate at very high frequency.

Description :

What parameters are to be considered when choosing a MOSFET?

Description : What is the transconductance of a MOSFET?

Description :

What is meant by pinch off voltage in MOSFET?

Description : What is channel length modulation in MOSFET?

Answer : Shortening of lenght of the inverted channel region with increase in drain bias for large drain biases due to which current increases with drain bias and output resistance decreases is called channel length modulation in MOSFET.

Description : What is meant by body effect in MOSFET?

Description : What is the use of a Mosfet?

Description : What is the work of MOSFET?

Description : What is depletion type MOSFET?..........

Answer : Depletion MOSFET: Depletion MOSFET is a MOSFET in which the channel already exists. If we apply a voltage between drain and source then the drain current will flow even if the gate to source ... in figure. The drain current will be reduced as the gate to source voltage made more negative.

Description : What is enhancement MOSFET?...............

Answer : Enhancement MOSFET: There are two types of MOSFET one is enhancement MOSFET and second is depletion MOSFET. In enhancement MOSFET channel is created by applying threshold voltage between gate and source ... mode. The enhancement MOSFET will not conduct if the gate to source voltage is zero.

Description : State advantages of MOSFET.

Answer : Advantages of MOSFET * MOSFETs provide greater efficiency while operating at lower voltages. * Absence of gate current results in high input impedance. * High switching speed. * They operate at lower ... due to lower resistance of channel. * They are easy to manufacture. * They are portable.

Description : Describe with neat sketch the construction and working principle of MOSFET.

Answer : Construction and working principle of MOSFET:  A) Depletion type MOSFET: Construction: The N-channel depletion type MOSFET is formed on P-type silicon substrate with two heavily ... accumulation of electrons and hence more current. Thus the MOSFET is a gate voltage controlled device.

Description : State the applications of MOSFET

Answer : Applications of MOSFET: i) Switching-mode-power-supplies (SMPS) and linear power supplies. ii) Brushless DC motor drives iii) Solid state DC relay iv) Automobile applications v) Stepper motor controller vi) Lighting controls vii) Solenoid drivers viii) Robotics ix) Induction heating

Description : Compare JFET with MOSFET.

Answer : Particulars JFET MOSFET 1) Type Voltage controlled device Voltage controlled device 2) Mode of operation Operates only in depletion mode Operates in depletion and enhancement ... 6) Gate connection Not isolated from substrate Isolated by SiO2 layer from substrate

Description : Describe the operation of N channel enhancement type MOSFET with diagram.

Answer : As its name indicates, this MOSFET operates only in the enhancement mode and has no depletion mode. It operates with large positive gate voltage only. It does not conduct when the ... of charge carriers attracted to the positive gate. Thus drain current is controlled by the gate potential.

Description :

A certain power MOSFET has a maximum junction temperature specification of 1500o C, a junction-to-case thermal resistance of 1.00 C/W, and a junction-to ambient thermal resistance of 600 C/W. If the ambient temperature is 300o C, then the maximum allowable power dissipation in the device will be A) 1.52 W B) 1.72 W C) 1.92W D) 2.00 W

Answer : A certain power MOSFET has a maximum junction temperature specification of 1500o C, a junction-to-case thermal resistance of 1.00 C/W, and a junction-to ambient thermal resistance of  ... 300o C, then the maximum allowable power dissipation in the device will be 2.00 W 

Description : When does the Body bias effect occur in an n-channel MOSFET?  A) When the Source voltage is less the Bulk voltage B) When the Source voltage is equal to or greater the Bulk voltage C) When the Drain voltage is equal to the Bulk voltage D) When the Gate voltage is equal to the Bulk Voltage 

Answer : When does the Body bias effect occur in an n-channel MOSFET?  A) When the Source voltage is less the Bulk voltage B) When the Source voltage is equal to or greater the Bulk voltage C) ... voltage is equal to the Bulk voltage D) When the Gate voltage is equal to the Bulk Voltage 

Description : The threshold voltage of an n- channel enhancement mode MOSFET is 0.5V when the device is biased at a gate voltage of 3V. Pinch off would be occurs at a drain voltage of (A) 1.5V (B) 2.5V (C) 3.5V (D) 4.5V

Answer : The threshold voltage of an n- channel enhancement mode MOSFET is 0.5V when the device is biased at a gate voltage of 3V. Pinch off would be occurs at a drain voltage of 2.5V

Description : Which phenomenon is present in thyristors but absent in BJT, MOSFET and IGBT ? (A) forward conduction (B) latching (C) forward blocking (D) reverse breakdown

Answer : Which phenomenon is present in thyristors but absent in BJT, MOSFET and IGBT ? (A) forward conduction (B) latching (C) forward blocking (D) reverse breakdown

Description : A MOSFET has how many terminals?

Answer : A MOSFET having three terminals 1st one is Gate (insulated), 2nd one is Source and 3rd one is Drain.

Description : How can we check a Mosfet?

Description :

Why Mosfet is called Mosfet?

Description : In MOSFET, the polarity of the inversion layers is the same as that of?

Answer : In MOSFET, the polarity of the inversion layers is the same as that of majority carriers in the source.

Description : MOSFET uses the electric field of?

Answer : MOSFET uses the electric field of gate capacitance.

Description : Is the input impedance of MOSFET more than BJT and FET?

Answer : Yes, the input impedance of MOSFET more than BJT and FET.

Description : Explain switching model of MOSFET.

Description : Explain MOSFET gate drive circuit and totem pole configuration.

Answer : MOSFET gate drive circuit: The turning on and turning off of MOSFET can be controlled from gate to source voltage signal. If the gate to source voltage of MOSFET exceeds threshold ... this configuration, the two switches (transistors) are used in totem pole arrangement with a comparator.

Description : Explain the formation of parasitic BJT and parasitic diode in Power MOSFET. Can parasitic diode be used in same power electronics applications?

Answer : Parasitic Diode: The parasitic diode is in between drain and source. The MOSFET structure itself contains parasitic diode or body drain diode. This parasitic diode allows the reverse flow of current when the ... of MOSFET as a BJT collector. Parasitic BJT operates in the cut-off region.

Description : Operating frequency of power MOSFET is higher than that of power BJT. Justify the statement.

Answer : Power MOSFET have high turning on and turning off capability high switching speed of MOSFET is due to the high rate of change of drain voltage. The switching losses of power MOSFET ... lower frequency. Hence, operating frequency of power MOSFET is higher than that of power BJT.

Description : Justify the statement. Antiparallel diode is connected across MOSFET.

Answer : In MOSFET current is flow from drain to source but when the load is inductive the current may flow in opposite direction. To avoid the opposite flow of current and to protect MOSFET the antiparallel diode is connected across MOSFET.

Description : parallel operation of MOSFET can be done more easily as compared to thyristor. why?

Answer : Parallel operation of MOSFET can be done more easily as compared to thyristor because the resistance of MOSFET is increases with increase in temperature. MOSFET have the positive temperature coefficient. In ... the parallel operation of MOSFET can be done more easily as compared to the thyristor.

Description : Justify. Power MOSFET is operated at high enough gate source voltage to minimize the conduction losses. 

Answer : MOSFET is metal oxide field effect transistor. MOSFET is a voltage controlled device. MOSFET is majority carrier device. MOSFET are of two one is n-channel MOSFET and p-channel MOSFET. Gate, ... . Hence, power MOSFET is operated at high enough gate-source voltage to minimize the conduction losses.

Description : Explain difference between enhancement MOSFET and depletion type MOSFET.

Answer : In enhancement MOSFET channel is not initially exists but in depletion MOSFET channel is already exists. In case of depletion MOSFET if the voltage is applied between drain and source the drain current will flow ... a channel. depletion MOSFET & enhancement MOSFET

Description : Compare BJT, MOSFET and IGBT .

Answer : BJT MOSFET IGBT BJT is a current controlled device. MOSFET is a voltage controlled device. IGBT is a voltage controlled device. The input impedance of BJT is low. ... is minority carrier device. MOSFET is majority carrier device. IGBT is minority carrier device.

Description : Explain the series and parallel operation of MOSFET. Which is suitable and why?

Answer : Series operation of MOSFET: To increase voltage handling capability MOSFETs are connected in series. When the MOSFETs are connected in series each MOSFET should turn on and turn off ... on and turn off time and transconductance. Each MOSFET should share current equally.  

Description :

Answer : Because it has a higher switching frequency and heat tolerance.

Description :

Answer : ON state losses of IGBT is less as compared to MOSFET and BJT.

Description :

Answer : No, MOSFET is not the curent controlled device. The current between drain and source which is drain current is controlled by applying a voltage between gate and source hence MOSFET is a voltage controlled device. 

Description :

Answer : already answered here is mosfet current controlled device?

Description :

Answer : MOSFET provides better efficiency at high frequency and its high speed switching losses are less hence MOSFET is used for high frequency.

Description : Compared to MOSFET operational amplifier, BJT operational amplifier has  A) Higher input resistance B) Higher slew rate C) Lower input current D) Higher voltage gain

Description : What are the main constructional differences between a MOSFET and a BJT? What effect do they have on the current conduction mechanism of a MOSFET? 

Answer : A MOSFET like a BJT has alternating layers of p and n type semiconductors. However, unlike BJT the p type body region of a MOSFET does not have an external electrical connection. The gate ... .  Distributed under Creative Commons Attribution-ShareAlike - CC BY-SA. Version 2 EE IIT, Kharagpur

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