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already answered here is mosfet current controlled device?

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Description :

Answer : MOSFET  are voltage controlled devices.

Description :

Answer : No, BJT is a current controlled device .

Description :

Answer : No, IGBT is not the current controlled device. IGBT is a voltage controlled device. IGBT have combine qualities of MOSFET and BJT. The high switching speed of MOSFET and low conduction losses of BJT. Also, IGBT which stands for Insulated Gate Bipolar Transistor have high input impedance.

Description :

Answer : Thyristor can only be turned on by small gate pulse but it cannot be turn off by using gate hence thyristor is called semi controlled device.

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 :

Answer : BJT is current controlled device.

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 :

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 : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque  (1) Decreases (2) Increases (3) Remains constant (4) None of the above

Answer : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque Increases 

Description : A current controlled voltage source is equivalent to :  (A) series voltage feed -back amplifier (B) shunt current feed -back amplifier (C) shunt voltage feed -back amplifier (D) series current feed -back amplifier

Answer : A current controlled voltage source is equivalent to : shunt voltage feed -back amplifier

Description : In voltage source converter based HVDC transmission system the active power is controlled by changing (A) phase angle of the converter ac input voltage (B) supply frequency of the converter ac input voltage (C) magnitude of the converter ac input voltage (D) DC voltage at the inverter terminals

Answer : In voltage source converter based HVDC transmission system the active power is controlled by changing phase angle of the converter ac input voltage

Description : For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is

Answer : For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is 25 x 25

Description :

What is meant by pinch off voltage in MOSFET?

Description :

Answer : In  BJT  there  is  movement  of   electrons  and  holes   accros  the  junctions  which  is  basicaly  current  flow.

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

Description : State classification of Phase controlled rectifiers.

Answer : Classification of phase controlled rectifiers:

Description : Single-phase mid-point controlled rectifier with RL load

Answer : Single-phase mid-point controlled rectifier with RL load : The circuit configuration of single-phase midpoint controlled rectifier is shown in the figure. During positive half-cycle of ... some part of next positive half-cycle of voltage with reversed polarity can appear across load.

Description : Single-phase Midpoint controlled rectifier with Resistive load

Answer : Single-phase Midpoint controlled rectifier with Resistive load:  1) During positive half cycle of AC supply, a is positive with respect to b , this makes T1 forward biased and T2 is reverse ... voltage reverses the polarity and T2 is turned off. The operation is as shown in waveforms.

Description : Give the operation of single phase full wave bridge controlled converter with RL load with a neat diagram. Also draw its waveform.

Answer : Single phase fully control bridge converter with RL load: 1. During positive half cycle of input voltage, T1 and T2 are forward biased and during negative half cycle, T3 and T4 are forward biased. Therefore, T1-T2 ... cycle till the firing of next pair of SCRs as shown in the waveform.

Description : Draw a neat diagram of 1Ф half wave controlled converter with RL load. Give its operation.

Answer : Single phase fully controlled half wave converter:  The circuit diagram of single-phase half-wave controlled rectifier with RL load and without freewheeling diode is shown in Fig. (a). The SCR T is ... , when again pulse is applied, the SCR is turned on & the above cycle is repeated. 

Description : A 3 -phase, fully controlled, converter is feeding power into a DC load at a constant current of 150 A, the rms value of the current flowing through each thyristor of the converter is

Answer : A 3 -phase, fully controlled, converter is feeding power into a DC load at a constant current of 150 A, the rms value of the current flowing through each thyristor of the converter is 150/√3

Description : When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a load is 30°, the displacement power factor of the rectifier is

Answer : When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a load is 30°, the displacement power factor of the rectifier is √3/2

Description : A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is (A) 4.5 V (B) 6.75 V (C) 9 V (D) 13.5 V

Answer : A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is 9 V

Description : The device which allows reverse power flow and withstands highest switch frequency is (A) GTO (B) MOSFET (C) IGBT (D) Inverter grade SCR

Answer : The device which allows reverse power flow and withstands highest switch frequency is MOSFET

Description : Why transistor is called as bipolar device.

Answer : BJT is called bipolar device because in BJT current conduction takes place due to majority as well as minority charge carriers that is because of electrons as well as holes.

Description :

Answer : Thyristor can be turn on by positive gate pulse and the current will continue to flow through the device even when the gate voltage is low hence thyristor is called latching device.

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 : 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 : 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 : 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 : 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 :

Why Mosfet is called Mosfet?

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 : Application one lamp controlled from two places

Answer : Application one lamp controlled from two places: 1. For Stair case wiring 2. Hospital Wiring ( For operating the lamp in room and nursing station) 3. Bedroom Lighting. 

Description : How are nuclear reactors controlled? Explain two different methods in brief.

Answer : Nuclear reactor is controlled using control rods: Control rods are made up of very high neutron absorbing material like boron, cadmium. By adjusting height of control rods on reactor core ... of nuclear reaction will increase. Whereas by pushing control rod towards the core it will reduce.

Description :

Answer : The speed of a locomotive is controlled by gear box.

Description :

Answer : The gravity controlled instrument has crowded scale because current is proportional to sine of deflection angle.

Description : How many servos can be controlled by Arduino?

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