Description : A modern power semiconductor device IGBT is combines the characteristics of a) BJT and MOSFET b) FCT and GTO c) SCR and MOSFET d) SCR and BJT
Last Answer : Ans: BJT and MOSFET
Description : Operating frequency of power MOSFET is higher than that of power BJT. Justify the statement.
Last 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 : Describe triggering of SCR using UJT relaxation oscillator.
Last Answer : I need it's operation
Description : The seven segment arrangement for numerical display on consoles, test meters and other applications can be either ________________. A. UJT or BJT B. BCD or OCD C. JFET or IGFET D. LED or LCD
Last Answer : Answer: D
Description : As compared to power MOSFET, a BJT has (a) Lower switching losses but higher conduction losses (b) Higher switching losses and higher conduction losses (c) Higher switching losses but lower conduction losses (d) Lower switching losses and lower conduction losses.
Last Answer : As compared to power MOSFET, a BJT has Higher switching losses but lower conduction losses
Description : Explain the formation of parasitic BJT and parasitic diode in Power MOSFET. Can parasitic diode be used in same power electronics applications?
Last 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.
Last Answer : Because it has a higher switching frequency and heat tolerance.
Description : What is a thyristor? What is an SCR?
Last Answer : A thyristor is a solid-state semiconductor device with four layers of alternating N and P-type material. They act as bi stable switches, conducting when their gate receives a current trigger, and continue ... ) is a four-layer solid state device that controls current. It is a type of thyristor.
Description : Is the input impedance of MOSFET more than BJT and FET?
Last Answer : Yes, the input impedance of MOSFET more than BJT and FET.
Description : Indicatewhich ofthe followingfrequencies cannotbe used forreliablebeyond-the-horizon terrestrial communicationswithoutrepeaters: a. 20 kHz b. 15 MHz c. 900 MHz d. 12GHz
Last Answer : d. 12GHz
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
Last 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 : 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?
Last 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
Description : Compare BJT, MOSFET and IGBT .
Last 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.
Last Answer : Yes IGBT is costlier than BJT and MOSFET.
Last Answer : ON state losses of IGBT is less as compared to MOSFET and BJT.
Description : The output power of a filter is 100 mW, when the signal frequency is 6 kHz. When the frequency is increased to 25 kHz, the output power falls to 50 mW. What is the dB change in power ? (a) -3 dB (b) -5 dB (c) -7 dB (d) -2 dB
Last Answer : The output power of a filter is 100 mW, when the signal frequency is 6 kHz. When the frequency is increased to 25 kHz, the output power falls to 50 mW. What is the dB change in power ? -3 dB
Description : Low pass filter with cut off frequency of 100 kHz and high pass filter with cut off frequency of 50 kHz are connected in tandem, the resultant filter is Low pass filter with cut off frequency of 100 kHz ... kHz Band pass filter with pass band from 50 kHz to 100 kHz. None of the above.
Last Answer : Low pass filter with cut off frequency of 100 kHz and high pass filter with cut off frequency of 50 kHz are connected in tandem, the resultant filter is Band pass filter with pass band from 50 kHz to 100 kHz.
Description : If the clock frequency to the circuit shown in the illustration were 100 kHz, what would be indicated at the output of 'FF-C'? EL-0087 A. 10.1 kHz B. 12.5 kHz C. 805 kHz D. 1010 kHz
Last Answer : Answer: B
Description : In acoustics, if the volume of the room is 200 m3 then at what frequency the coefficient of absorption is measured? A. 120 kHz B. 120 Hz C. 100 Hz D. 150 Hz
Last Answer : B. 120 Hz
Description : What is the typical frequency used for communicating to submerged submarines? A. 100 Hz B. 500 Hz C. 4 kHz D. 200 Hz
Last Answer : A. 100 Hz
Description : Human ear is most sensitive to noise in the following frequency ranges: (A) 1-2 KHz (B) 100-500 Hz (C) 10-12 KHz (D) 13-16 KHz
Last Answer : (A) 1-2 KHz
Description : A tuned circuit has a Q of 100 at its resonant frequency of 500 kHz. Its bandwidth is _____kHz. (A) 50000 (B) 0.2 (C) 600 (D) 5
Last Answer : A tuned circuit has a Q of 100 at its resonant frequency of 500 kHz. Its bandwidth is 5 kHz.
Description : A series RLC circuit has a resonant frequency of 1 KHz and a quality factor Q = 100. If each of the R,L and C is doubled from its original value, the new Q of the circuit is: (1) 25 (2) 50 (3) 100 (4) 200
Last Answer : A series RLC circuit has a resonant frequency of 1 KHz and a quality factor Q = 100. If each of the R,L and C is doubled from its original value, the new Q of the circuit is: 200.
Description : Silicon transistors are preferred because: (a) High operating temperature (b) Low leakage current (c) Suited to high frequency circuits (d) All
Last Answer : (d) All
Description : Power BJT is a current controlled device. Why?
Last Answer : Because the output (collector) current can be controlled by base current.
Description : A silicon controlled rectifier (SCR) is a solid state device used to change ________________. A. DC to AC and control relatively low load current B. AC to DC and control relatively high load ... to AC and control relatively high load current D. AC to DC and control relatively low load current
Description : The materials having low retentivity are suitable for making (a) weak magnets (b) temporary magnets (c) permanent magnets (d) none of the above
Last Answer : (b) temporary magnets
Description : The most suitable metal for making permanent magnet is a) Iron b) Steel c) Silver d) Copper
Last Answer : a) Iron
Description : Power MOSFET is a voltage controlled device. Why?
Last Answer : Because the output (drain) current can be controlled by gate-source voltage.
Description : The conduction loss versus device current characteristic of a power MOSFET is best approximated by (A) a parabola (B) a straight line (C) a rectangular hyperbola (D) an exponentially decaying function
Last Answer : The conduction loss versus device current characteristic of a power MOSFET is best approximated by a parabola
Description : Which ofthe followingcableswill have the highestlaunch power capability? a. 50/125/0.2 b. 85/125/0.275 c. 62.5/125/0.275 d. 100/140/0.3
Last Answer : d. 100/140/0.3
Description : A galvanometer having a resistance of 4.5 Ω can read up to 5 mA. If it is to read 100 V, then the high resistance to be used in series will be a) 19998 Ω b) 19995.8 Ω c) 19995.5 Ω d) 19996.5 Ω
Last Answer : c) 19995.5
Description : .Aslightis coupledin amultipointreflective device,thepowerisreduced by a. 1.5 dB b. 0.1 dB c. 0.5 dB d. 0.001 dB
Last Answer : c. 0.5 dB
Description : A device based on photo electric effect is called a) Photo sensitive b) Photo diode c) Photo synthesis d) Photo cell
Last Answer : d) Photo cell
Description : Aship-to-ship communicationssystemisplagued byfading.The bestsolutionseemstobe useof a. a more directional antenna b. a broadband antenna c. frequency diversity d. space diversity
Last Answer : c. frequency diversity
Description : Why is it necessary that incoming alternator frequency is more than bus bar?
Last Answer : Prior to paralleling alternators together, the frequency of the incoming alternator is made slightly higher. This is to ensure that the incoming generator will take some of the bus load. If the incoming ... onto the bus. If this happens it is possible to cause other generators to trip off line.
Description : Identify type of BJT configuration having following features : (i) BJT configuration having the least current gain. (ii) KIT configuration called as voltage follower. (iii) BJT ... configuration suitable for voltage amplification. (vi) BJT configuration having the least output impedance.
Last Answer : (i) BJT configuration having the least current gain : Common Base Configuration (ii) KIT configuration called as voltage follower: Common Collector Configuration (iii) BJT ... Emitter Configuration (vi) BJT configuration having the least output impedance: Common Collector Configuration
Description : For High frequency applications will you prefer MOSFET or IGBT? Why?
Last Answer : For High frequency applications, MOSFET is the right choice of the device.Because MOSFET has low switching losses compare to that of IGBT.General rule of thumb is for low-frequency applications ... For high frequency applications having frequency range of more than 200kHz, we have to use MOSFET
Last Answer : Yes MOSFET can operate at very high frequency.
Last Answer : MOSFET provides better efficiency at high frequency and its high speed switching losses are less hence MOSFET is used for high frequency.
Description : The application of mutual induction is: a. TV b. Radio c. Transformer d. Motor
Last Answer : c. Transformer
Description : The practical application of electrostatic is: (a) Photocopier (b) X-rays machines (c) Laser (d) All of above 42. The electric field lines emerge from the charges in: (a) Three dimensions (b) Two dimensions (c) One dimension (d) All of above
Last Answer : (a) Photocopier
Description : Explain the series and parallel operation of MOSFET. Which is suitable and why?
Last 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 : The absorption ofradiowaves bythe atmosphere depends on a. their frequency b. their distance from the transmitter c. the polarization of the waves d. the polarization of the atmosphere
Last Answer : a. their frequency
Description : Arange ofmicrowave frequenciesmore easilypassed bythe atmospherethan are theothersis called a a.window b. critical frequency c. gyro frequency range d. resonance in the atmosphere
Last Answer : a.window
Description : Distancesnearthe skip distance should beused forthe sky-wave propagation a. to avoid tilting b.topreventsky-wave andupper rayinterference c. to avoid the Faraday effect d. so as nor to exceed the critical frequency
Last Answer : b.topreventsky-wave andupper rayinterference
Description : Even though the main engine runs at varying speeds, how does the alternator maintain constant frequency?
Last Answer : By use of thyristor controlled frequency (rpm) converters.
Description : The minimum frequency required to eject electrons from a metallic surface is called a) Critical frequency b) Peak value of frequency c) Threshold frequency d)Photo frequency
Last Answer : c) Threshold frequency
Description : The minimum energy required to eject an electron from a metal surface is called a) Intensity b) Threshold frequency c) Work function d) Photo energy
Last Answer : c) Work function
Description : Can you guys explain the advantages of frequency converter against the star delta or soft starter?
Last Answer : ¬Soft starters A soft starter is, as you would expect, a device which ensures a soft starting of a motor. A softstarter has different characteristics to the other starting ... at rated current from zero to full speed. Frequency converters are becoming cheaper all the time.