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.
asked
Feb 6, 2018
by
anonymous
Answer :
Because it has a higher switching frequency and heat tolerance.
asked
Sep 15, 2017
by
anonymous
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
asked
Apr 28, 2018
by
anonymous
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.
asked
Nov 10, 2017
by
anonymous
Answer :
ON state losses of IGBT is less as compared to MOSFET and BJT.
asked
Sep 13, 2017
by
anonymous
Description : Is the input impedance of MOSFET more than BJT and FET?
Answer :
Yes, the input impedance of MOSFET more than BJT and FET.
asked
Mar 19, 2018
by
anonymous
Answer :
Yes IGBT is costlier than BJT and MOSFET.
asked
Sep 29, 2017
by
anonymous
Answer :
MOSFET provides better efficiency at high frequency and its high speed switching losses are less hence MOSFET is used for high frequency.
asked
Sep 10, 2017
by
anonymous
Answer :
Active , Saturation , Cut-off region of operations in BJT.
asked
Sep 27, 2017
by
anonymous
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.
Answer :
Yes MOSFET can operate at very high frequency.
asked
Sep 22, 2017
by
anonymous
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.
asked
Dec 7, 2017
by
anonymous
Description : Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, respectively. Then the system frequency is (A) 50 Hz (B) 51 Hz (C) 51.25 Hz (D) 51.5 Hz
Answer :
Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, respectively. Then the system frequency is 50 Hz
asked
Apr 28, 2018
by
anonymous
Description : Explain the on state losses in power BJT.
Answer :
On state losses in power BJT: Transistor have four types of losses one is turn on state losses second is turn off state losses third is turn on switching losses and fourth is turn ... ON = VCE sat x IC With increasing collector current collector to emitter saturation voltage increases.
asked
Sep 15, 2017
by
anonymous
Answer :
In cut-off region of BJT both the emitter-base junction and collector-base junction are reverse biased.
asked
Sep 27, 2017
by
anonymous
Description : operating principle of PUT.
Answer :
Constructional diagram & Operating principle of PUT: The PUT is a PNPN device similar to SCR, but its operation is similar to the UJT. The PUT behave like a UJT whose trigger voltage VP can be set ... low resistance and VAK ≈ 1V). The PUT is also referred to as a complementary SCR (CSCR).
asked
Oct 13, 2019
by
anonymous
Description : In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load, the input source current is (A) sinusoidal current (B) constant dc current (C) continuous rectangular pulses (D) alternating rectangular pulses
Answer :
In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load, the input source current is alternating rectangular pulses
asked
Apr 28, 2018
by
anonymous
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
asked
Apr 28, 2018
by
anonymous
Description : What is the difference between beta and forced beta for BJT?
asked
Feb 20, 2018
by
anonymous
Description : Explain open emitter BJT drive circuit.
Answer :
open emitter BJT drive circuit:
asked
Feb 19, 2018
by
anonymous
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.
asked
Jul 25, 2019
by
anonymous
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
asked
Jul 25, 2019
by
anonymous
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
asked
Apr 28, 2018
by
anonymous
Description : Explain switching model of MOSFET.
asked
Mar 10, 2018
by
anonymous
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.
asked
Feb 19, 2018
by
anonymous
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.
asked
Dec 7, 2017
by
anonymous
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 : 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.
asked
Sep 15, 2017
by
anonymous
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.
asked
Sep 15, 2017
by
anonymous
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.
asked
Sep 15, 2017
by
anonymous
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.
asked
Sep 10, 2017
by
anonymous
Answer :
already answered here is mosfet current controlled device?
asked
Sep 10, 2017
by
anonymous
Description : An FET is a better chopper than a BJT because it has (A) lower offset voltage (B) higher series ON resistance (C) lower input current (D) higher input impedance
Answer :
An FET is a better chopper than a BJT because it has lower offset voltage
asked
Apr 26, 2018
by
anonymous
Description : What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016 revolutions and the meter constant in revolution is 420? A) 0.04 B) 1.04 C) 0.96 D) None of these
Answer :
What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016 revolutions and the meter constant in revolution is 420? A) 0.04 B) 1.04 C) 0.96 D) None of these
asked
Apr 29, 2018
by
anonymous
Description : A 230 V/460 V single-phase transformer operating at 20 A and unity power factor has primary referred resistance of 0.2 Ω and reactance of 0.5 Ω. The approximate primary induced emf is (A) 216 V (B) 226 V (C) 234 V (D) 236 V
Answer :
A 230 V/460 V single-phase transformer operating at 20 A and unity power factor has primary referred resistance of 0.2 Ω and reactance of 0.5 Ω. The approximate primary induced emf is 226 V
asked
Apr 28, 2018
by
anonymous
Answer :
Annual operating expenditure of a power plant consists of fixed charges, semi-fixed charges, running charges.
asked
Mar 20, 2018
by
anonymous
Description : The command line interpreter that enables the users to interact with operating system is called the A) Window B) Shell C) Process D) Kernel
Answer :
The command line interpreter that enables the users to interact with operating system is called the Shell
asked
Jun 18, 2018
by
anonymous
Description : What is the value of Beta in power BJT?
Answer :
The beta value in power BJT is 5 to 10.
asked
Sep 20, 2017
by
anonymous
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
asked
Jun 18, 2018
by
anonymous
Answer :
MOSFET have high current losses due to High on state resistance. Hence MOSFET is used for low power applications.
asked
Sep 22, 2017
by
anonymous
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.
asked
Mar 19, 2018
by
anonymous
Description : The SCR would be turned OFF by voltage reversal of applied anode-cathode ac supply frequency of A) 10 kHz B) 10 Hz C) 5 kHz D) 5 Hz
asked
Jun 18, 2018
by
anonymous
Description : Which of the following thyristors can be used for high frequency of operation? A) TRIAC B) DIAC C) SCR D) GTO
Answer :
Which of the following thyristors can be used for high frequency of operation? A) TRIAC B) DIAC C) SCR D) GTO
asked
Jun 18, 2018
by
anonymous
Description : Transistor operating configurations
Answer :
Transistor operating configurations
asked
May 20, 2019
by
anonymous
Description : Draw construction of Megger and write operating principle of it.
Answer :
Megger: Working: Two coils the current coil and pressure coil are mounted at an angle on the same spindle and form the part of the moving system. These coils are connected to a small hand driven ... . When the instrument is not working the pointer may rest at any position on the dial.
asked
Sep 6, 2018
by
anonymous
Description : Explain the operating principle of LASER and list applications of LASER diode.
Answer :
A basic construction of Laser diode is as shown . A PN junction is formed by two layers of doped gallium arsenide. There is highly reflective surface at one end of PN junction and ... 6. laser scanning and light beam illumination. 7. Military applications 8. Medical surgery 9.Diamond cutting
asked
Sep 5, 2018
by
anonymous
Description : The operating point of a protective current transformer is near the
Answer :
The operating point of a protective current transformer is near the Ankle point
asked
May 8, 2018
by
anonymous
Description : The operating time of instantaneous relay is
Answer :
The operating time of instantaneous relay is 0.1 sec
asked
May 3, 2018
by
anonymous
Description : A minimum clearance of 6.3 m to ground is required for overhead lines when operating voltages are : (A) less than 66 kV (B) lie between 66 kV and 110 kV (C) more than 165 kV (D) lie between 110 kV and 165 kV
Answer :
A minimum clearance of 6.3 m to ground is required for overhead lines when operating voltages are : lie between 66 kV and 110 kV
asked
Apr 30, 2018
by
anonymous
Description : In a single-phase induction motor, the operating direction is determined by the ________ A) Rotor B) Stator C) Starting circuit D) None of these
Answer :
In a single-phase induction motor, the operating direction is determined by the Starting circuit
asked
Apr 29, 2018
by
anonymous