MCQOPTIONS
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MCQOPTIONS
This section includes 335 Mcqs, each offering curated multiple-choice questions to sharpen your Power Electronics knowledge and support exam preparation. Choose a topic below to get started.
| 251. |
Printer in which printing head and paper is forced together to form the letters is called |
| A. | impact printer |
| B. | non impact printer |
| C. | page printers |
| D. | line printers |
| Answer» B. non impact printer | |
| 252. |
Printer which is used to produce low-cost posters and handouts is |
| A. | dye-sublimation |
| B. | thermal-wax |
| C. | laser |
| D. | inkjet |
| Answer» B. thermal-wax | |
| 253. |
Types of computer impact printer are |
| A. | dot matrix printers |
| B. | daisy wheel printers |
| C. | line printers |
| D. | all of these |
| Answer» E. | |
| 254. |
Scanning technology, used in banks to read the numbers at the bottom of checks is |
| A. | MICR |
| B. | OCR |
| C. | OMR |
| D. | GRE |
| Answer» B. OCR | |
| 255. |
The OCR is used for the preparation of |
| A. | electricity bills |
| B. | insurance premium |
| C. | telephone bills |
| D. | all of these |
| Answer» E. | |
| 256. |
Hand-held device which is used to pick options that are displayed on a computer screen is known as |
| A. | keyboard |
| B. | mouse |
| C. | joystick |
| D. | stylus pen |
| Answer» C. joystick | |
| 257. |
Laser Jet printer speeds are measured in pages per minute (ppm). what do we use to measure dot-matrix printers? |
| A. | lines per inch |
| B. | lines per sheet |
| C. | characters per inch |
| D. | characters per second |
| Answer» E. | |
| 258. |
Higher the magnitude of the gate pulse |
| A. | lesser is the time required to inject the charges |
| B. | greater is the time required to inject the charges |
| C. | greater is the value of anode current |
| D. | lesser is the value of anode current |
| Answer» B. greater is the time required to inject the charges | |
| 259. |
For a power transistor, if the base current IB is increased keeping VCE constant, then |
| A. | IC increases |
| B. | IC decreases |
| C. | IC remains constant |
| D. | none of the mentioned |
| Answer» B. IC decreases | |
| 260. |
For a power transistor, if the forward current gain α = 0.97, then β = ? |
| A. | 0.03 |
| B. | 2.03 |
| C. | 49.24 |
| D. | 32.33 |
| Answer» E. | |
| 261. |
In a GTO the n+ layer forms the |
| A. | anode & gate |
| B. | cathode & gate |
| C. | cathode |
| D. | gate |
| Answer» D. gate | |
| 262. |
For an SCR the total turn-on time consists ofi) Delay timeii) Rise time andiii) Spread timeDuring the delay time the |
| A. | anode current flows only near the gate |
| B. | anode current rises from zero to very high value |
| C. | losses are maximum |
| D. | anode to cathode voltage is zero |
| Answer» B. anode current rises from zero to very high value | |
| 263. |
With the anode positive with respect to the cathode & the gate circuit open, the SCR is said to be in the |
| A. | reverse blocking mode |
| B. | reverse conduction mode |
| C. | forward blocking mode |
| D. | forward conduction mode |
| Answer» D. forward conduction mode | |
| 264. |
The DIAC can be represented by |
| A. | two SCRs in anti-parallel |
| B. | two SCRs in parallel |
| C. | two diodes in anti-parallel |
| D. | two diodes in parallel |
| Answer» D. two diodes in parallel | |
| 265. |
The major drawback of the first generation IGBTs was that, they had |
| A. | latch-up problems |
| B. | noise & secondary breakdown problems |
| C. | sluggish operation |
| D. | latch-up & secondary breakdown problems |
| Answer» E. | |
| 266. |
The maximum rms current of an SCR is 50 A. For a 120° sine wave conduction the form factor (FF) = 1.878Find the average on-state current rating (ITAV). |
| A. | 93.9 A |
| B. | 174 A |
| C. | 26.62 A |
| D. | 68.52 A |
| Answer» D. 68.52 A | |
| 267. |
In the internal structure of a MOSFET, a parasitic BJT exists between the |
| A. | source & gate terminals |
| B. | source & drain terminals |
| C. | drain & gate terminals |
| D. | there is no parasitic BJT in MOSFET |
| Answer» C. drain & gate terminals | |
| 268. |
The output characteristics of a MOSFET, is a plot of |
| A. | Id as a function of Vgs with Vds as a parameter |
| B. | Id as a function of Vds with Vgs as a parameter |
| C. | Ig as a function of Vgs with Vds as a parameter |
| D. | Ig as a function of Vds with Vgs as a parameter |
| Answer» C. Ig as a function of Vgs with Vds as a parameter | |
| 269. |
The sink to ambient thermal resistance of SCR θsA |
| A. | depends on the flatness of the device |
| B. | depends on the length of the device |
| C. | depends on the current carrying capabilities |
| D. | is independent on thyristor configuration |
| Answer» E. | |
| 270. |
In IGBT, the n– layer above the p+ layer is called as the |
| A. | drift layer |
| B. | injection layer |
| C. | body layer |
| D. | collector Layer |
| Answer» B. injection layer | |
| 271. |
In a power transistor, the IB vs VBE curve is |
| A. | a parabolic curve |
| B. | an exponentially decaying curve |
| C. | resembling the diode curve |
| D. | a straight line Y = IB |
| Answer» D. a straight line Y = IB | |
| 272. |
For an SCR the total turn-on time consists ofi) Delay timeii) Rise time and theiii) Spread timeThe spread time interval depends upon |
| A. | the value of gate current |
| B. | junction temperature |
| C. | area of the cathode |
| D. | area of the anode |
| Answer» D. area of the anode | |
| 273. |
Latching current for an SCR is 100 mA, DC source of 200 V is also connected from the SCR to the L load. Compute the minimum width of the gate pulse required to turn on the device. Take L = 0.2 H. |
| A. | 50 μsec |
| B. | 100 μsec |
| C. | 150 μsec |
| D. | 200 μsec |
| Answer» C. 150 μsec | |
| 274. |
The total thermal resistance between junction and ambient θjA is 10°C/W. θjc is 2°C/W. θcs is 4°C/W. θsA = ? |
| A. | 4°C/W |
| B. | 2°C/W |
| C. | 10°C/W |
| D. | 16°C/W |
| Answer» B. 2°C/W | |
| 275. |
The RCT (Reverse Conducting Thyristor) has |
| A. | a diode in series with the SCR |
| B. | a diode in anti-parallel with the SCR |
| C. | two SCR's in anti-parallel |
| D. | none of the mentioned |
| Answer» C. two SCR's in anti-parallel | |
| 276. |
At present, the state-of-the-art semiconductor devices are begin manufactured using |
| A. | Semiconducting Diamond |
| B. | Gallium-Arsenide |
| C. | Germanium |
| D. | Silicon-Carbide |
| Answer» E. | |
| 277. |
The SOA for a MOSFET is plotted for |
| A. | Id versus Vds |
| B. | Ig versus Id |
| C. | Ig versus Vds |
| D. | Id versus Vgs |
| Answer» B. Ig versus Id | |
| 278. |
The amp2-sec rating of the SCR specifies |
| A. | The power dissipated by the device when fault occurs |
| B. | The energy dissipated by the device when fault occurs |
| C. | The energy that the device can absorb before the fault is cleared |
| D. | The energy that the device can absorb while operating in the forward blocking mode. |
| Answer» D. The energy that the device can absorb while operating in the forward blocking mode. | |
| 279. |
A GTO can be represented by two transistors T1 & T2. The current gain of both transistors are α1 and α2 respectively. A low value of gate current requires |
| A. | low value of α1 and α2 |
| B. | low value of α1 and high value of α2 |
| C. | high value of α1 and low value of α2 |
| D. | high values of α1 and α2 |
| Answer» C. high value of α1 and low value of α2 | |
| 280. |
The value of anode current required to maintain the conduction of an SCR even though the gate signal is removed is called as the |
| A. | holding current |
| B. | latching current |
| C. | switching current |
| D. | peak anode current |
| Answer» C. switching current | |
| 281. |
For an SCR in the forward blocking mode (practically) |
| A. | leakage current does not flow |
| B. | leakage current flows from anode to cathode |
| C. | leakage current flows from cathode to anode |
| D. | leakage current flows from gate to anode |
| Answer» C. leakage current flows from cathode to anode | |
| 282. |
The voltage safety factor (VSF) for an SCR is the ratio of |
| A. | peak working voltage & peak reverse repetitive voltage |
| B. | dv/dt & di/dt |
| C. | peak repetitive reverse voltage & maximum value of input voltage |
| D. | peak repetitive reverse voltage & rms value of input voltage |
| Answer» D. peak repetitive reverse voltage & rms value of input voltage | |
| 283. |
The area under the curve of the gate characteristics of thyristor gives the |
| A. | total average gate current |
| B. | total average gate voltage |
| C. | total average gate impedance |
| D. | total average gate power dissipation |
| Answer» E. | |
| 284. |
For an SCR the average & rms values of current are I/4 & I/2 respectively. Calculate the average on-state current rating (ITAV). Take maximum RMS on-state current = 35 A. |
| A. | 8.78 A |
| B. | 10.10 A |
| C. | 17.5 A |
| D. | 24.74 A |
| Answer» D. 24.74 A | |
| 285. |
In IGBT, the p+ layer connected to the collector terminal is called as the |
| A. | drift layer |
| B. | injection layer |
| C. | body layer |
| D. | collector Layer |
| Answer» C. body layer | |
| 286. |
The value of β is given by the expression |
| A. | IC/IB |
| B. | IC/IE |
| C. | IE/IC |
| D. | IE/IB |
| Answer» B. IC/IE | |
| 287. |
A tangent drawn from the Y-axis to the Pavg on the gate characteristics gives the value of the |
| A. | maximum value of gate-source resistance |
| B. | minimum value of gate-source resistance |
| C. | maximum value of gate-source power |
| D. | minimum value of gate-source power |
| Answer» C. maximum value of gate-source power | |
| 288. |
From the two transistor (T1 & T2) analogy of SCR, the total anode current of SCR is ___________ in the equivalent circuit. |
| A. | the sum of both the base currents |
| B. | the sum of both the collector current |
| C. | the sum of base current of T1 & collector current of T2 |
| D. | the sum of base current of T2 & collector current of T1 |
| Answer» C. the sum of base current of T1 & collector current of T2 | |
| 289. |
The two transistor model of the SCR can obtained by |
| A. | bisecting the SCR vertically |
| B. | bisecting the SCR horizontally |
| C. | bisecting the SCRs top two & bottom two layers |
| D. | bisecting the SCRs middle two layers |
| Answer» E. | |
| 290. |
False triggering of the SCRs by varying flux & noise is avoided by using |
| A. | F.A.C.L.F & C.B |
| B. | Shielded cables & twisted gate leads |
| C. | Snubber circuits |
| D. | di/dt inductor in series with the gate terminal |
| Answer» C. Snubber circuits | |
| 291. |
An IGBT is also know as |
| A. | MOIGT (Metal oxide insulated gate transistor) |
| B. | COMFET (Conductively modulated FET) |
| C. | GEMFET (Grain modulated FET) |
| D. | all of the mentioned |
| Answer» E. | |
| 292. |
In the ___________ type of mounting the SCR is pressed between two heat sinks |
| A. | bolt-down mounting |
| B. | stud-mounting |
| C. | press-pak mounting |
| D. | cross-fit mounting |
| Answer» D. cross-fit mounting | |
| 293. |
The SITH is a |
| A. | normally-off device |
| B. | normally-on device |
| C. | uncontrollable device |
| D. | none of the mentioned |
| Answer» C. uncontrollable device | |
| 294. |
The SITH (Static Induction Thyristor) is a |
| A. | 4 terminal, self-controlled device |
| B. | 3 terminal, self-controlled device |
| C. | 4 terminal, un-controllable device |
| D. | 3 terminal, un-controllable device |
| Answer» C. 4 terminal, un-controllable device | |
| 295. |
The average gate power dissipation for an SCR is 0.5 Watts the voltage applied to the gate is Vg = 10 V. What is the maximum value of current Ig for safe operation? |
| A. | 0.25 A |
| B. | 10 A |
| C. | 0.05 A |
| D. | 0.1 A |
| Answer» D. 0.1 A | |
| 296. |
Thyristors are used in electronic crowbar protection circuits because it possesses |
| A. | high surge current capabilities |
| B. | high amp 2-sec rating |
| C. | less switching losses |
| D. | voltage clamping properties |
| Answer» B. high amp 2-sec rating | |
| 297. |
Two parallel connect SCRs have same voltage drop (Vt) having rated current = 2I1. SCR-1 carries a current of I1=2.6 A whereas SCR-2 carries a current of I2=1.4 A. Find the string efficiency. |
| A. | 0.45 |
| B. | 0.77 |
| C. | 0.92 |
| D. | 0.84 |
| Answer» C. 0.92 | |
| 298. |
The SITH |
| A. | has high reverse blocking capabilities as compared to CTs |
| B. | has low reverse blocking capabilities as compared to CTs |
| C. | has no reverse blocking capabilities |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 299. |
Let's say that a transistor is operating at the middle of the load line, then a decrease in the current gain would |
| A. | move the Q point up |
| B. | move the Q point down |
| C. | result in to & fro motion of the Q point |
| D. | not change the Q point |
| Answer» C. result in to & fro motion of the Q point | |
| 300. |
Pav x (θjc + θcs + θsA) = |
| A. | Maximum specified temperature |
| B. | Energy lost |
| C. | Difference in temperature between junction & ambient |
| D. | Sum of junction & ambient temperature |
| Answer» D. Sum of junction & ambient temperature | |