MCQOPTIONS
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MCQOPTIONS
This section includes 227 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
Power electronics essentially deals with control of a.c. power at ___________. |
| A. | requencies above 20 kHz |
| B. | requencies above 1000 kHz |
| C. | requencies less than 10 Hz |
| D. | 0 Hz frequency |
| Answer» E. | |
| 152. |
A triac is equivalent to two SCRs ___________. |
| A. | n parallel |
| B. | n series |
| C. | n inverse-parallel |
| D. | one of the above |
| Answer» D. one of the above | |
| 153. |
The triac is ___________. |
| A. | ike a bidirectional SCR |
| B. | four-terminal device |
| C. | ot a thyristor |
| D. | one of the above |
| Answer» B. four-terminal device | |
| 154. |
When a UJT is turned ON, the resistance between emitter terminal and lower base terminal ___________ |
| A. | emains the same |
| B. | s decreased |
| C. | s increased |
| D. | one of the above |
| Answer» C. s increased | |
| 155. |
A diac has ___________ semiconductor layers |
| A. | hree |
| B. | wo |
| C. | our |
| D. | one of the above |
| Answer» B. wo | |
| 156. |
A Triac has three terminals viz ___________ |
| A. | rain, source, gate |
| B. | wo main terminal and a gate terminal |
| C. | athode, anode, gate |
| D. | one of the above |
| Answer» C. athode, anode, gate | |
| 157. |
The V-I characteristics for a triac in the first and third quadrants are essentially identical to those of ___________ in its first quadrant |
| A. | ransistor |
| B. | CR |
| C. | JT |
| D. | one of the above |
| Answer» C. JT | |
| 158. |
The device that does not have the gate terminal is ___________. |
| A. | riac |
| B. | ET |
| C. | CR |
| D. | iac |
| Answer» E. | |
| 159. |
In a UJT, the p-type emitter is ___________ doped |
| A. | ightly |
| B. | eavily |
| C. | oderately |
| D. | one of the above |
| Answer» C. oderately | |
| 160. |
When the emitter terminal of a UJT is open, the resistance between the base terminal is generally ___________. |
| A. | igh |
| B. | ow |
| C. | xtremely low |
| D. | one of the above |
| Answer» B. ow | |
| 161. |
The device that exhibits negative resistance region is ___________. |
| A. | iac |
| B. | riac |
| C. | ransistor |
| D. | JT |
| Answer» E. | |
| 162. |
A diac is turned on by ___________. |
| A. | breakover voltage |
| B. | ate voltage |
| C. | ate current |
| D. | one of the above |
| Answer» B. ate voltage | |
| 163. |
A UJT is sometimes called ___________ diode. |
| A. | ow resistance |
| B. | igh resistance |
| C. | ingle-base |
| D. | ouble-base |
| Answer» E. | |
| 164. |
After peak point, the UJT operates in the ___________ region. |
| A. | ut-off |
| B. | aturation |
| C. | egative resistance |
| D. | one of the above |
| Answer» D. one of the above | |
| 165. |
Between the peak point and the valley point of UJT emitter characteristics we have ___________ region |
| A. | aturation |
| B. | egative resistance |
| C. | ut-off |
| D. | one of the above |
| Answer» C. ut-off | |
| 166. |
A triac can pass a portion of ___________ half-cycle through the load. |
| A. | nly positive |
| B. | nly negative |
| C. | oth positive and negative |
| D. | one of the above |
| Answer» D. one of the above | |
| 167. |
Which of the following is not a characteristic of UJT? |
| A. | ntrinsic stand off ratio |
| B. | egative resistance |
| C. | eak-point voltage |
| D. | ilateral conduction |
| Answer» E. | |
| 168. |
A triac is a ___________ switch |
| A. | idirectional |
| B. | nidirectional |
| C. | echanical |
| D. | one of the above |
| Answer» B. nidirectional | |
| 169. |
A diac has ___________ terminals. |
| A. | wo |
| B. | hree |
| C. | our |
| D. | one of the above |
| Answer» B. hree | |
| 170. |
A diac has ___________ pn junctions |
| A. | our |
| B. | wo |
| C. | hree |
| D. | one of the above |
| Answer» C. hree | |
| 171. |
The UJT may be used as ___________. |
| A. | m amplifier |
| B. | sawtooth generator |
| C. | rectifier |
| D. | one of the above |
| Answer» C. rectifier | |
| 172. |
MOSFET can be used as a |
| A. | Current controlled capacitor |
| B. | Voltage controlled capacitor |
| C. | Current controlled inductor |
| D. | Voltage controlled inductors |
| Answer» C. Current controlled inductor | |
| 173. |
The early effect in a bipolar junction transistor is caused by |
| A. | Fast turn – on |
| B. | Fast turn – off |
| C. | Large collector - base reverse bias |
| D. | Large emmiter - base forward bias |
| Answer» D. Large emmiter - base forward bias | |
| 174. |
The effective channel length of a MOSFET in a saturation decreases with increase in |
| A. | gate voltage |
| B. | drain voltage |
| C. | drain voltage |
| D. | body voltage |
| Answer» C. drain voltage | |
| 175. |
The MOSFET switch in its on-state may be considered equivalent to |
| A. | resistor |
| B. | inductor |
| C. | capacitor |
| D. | battery |
| Answer» D. battery | |
| 176. |
An n-channel JFET has IDSS=2mA, and Vp=-4V. Its transconductance gm=(in mA/V) for an applied gate to source voltage VGS=-2V is |
| A. | 0.25 |
| B. | . 0.5 |
| C. | 0.75 |
| D. | 1 |
| Answer» C. 0.75 | |
| 177. |
In a p-n junction diode under reverse bias, the magnitude of electric field is maximum at |
| A. | the edge of the depletion region on the p-side |
| B. | the edge of the depletion region on the n-side |
| C. | the p-n junction |
| D. | the center of the depletion region on the n-side |
| Answer» D. the center of the depletion region on the n-side | |
| 178. |
Which of the following is not associated with p-n junction |
| A. | junction capacitance |
| B. | charge storage capacitance |
| C. | depletion capacitance |
| D. | channel length modulation |
| Answer» E. | |
| 179. |
A three phase fully controlled thyristor bridge converter is used as line commutated inverter to feed 50KW power at 420V DC to a three phase 415V(line), 50Hz as mains. Consider Dc link current to be constant. The rms current of the thyristor is [GATE 2007] |
| A. | 119.05A |
| B. | 79.37A |
| C. | 68.73A |
| D. | 39.68A |
| Answer» E. | |
| 180. |
A single phase fully controlled thyristor bridge ac-dc converter is operating at a firing angle of 25 degree, and an overlap angle 10 degree with constant dc output current of 20A. The fundamental power factor ( displacement factor) at input ac mains is [GATE 2007] |
| A. | 0.78 |
| B. | 0.827 |
| C. | 0.866 |
| D. | 0.9 |
| Answer» B. 0.827 | |
| 181. |
An SCR is considered to be a semi-controlled device because [GATE 2009] |
| A. | It can be turned OFF but not ON with a gate pule |
| B. | It conducts only during one half-cycle of an alternating current wave |
| C. | It can be turned ON but not OFF with a gate pulse1 |
| D. | It can be turned ON only during one half-cycle of an alternating voltage wave |
| Answer» D. It can be turned ON only during one half-cycle of an alternating voltage wave | |
| 182. |
Which one of the following statement is true |
| A. | MOSFET has positive temperature coefficient whereas BJT has negative temperature Coefficient |
| B. | Both MOSFET and BJT have positive temperature coefficient |
| C. | Both MOSFET and BJT have negative temperature coefficient |
| D. | MOSFET has negative temperature coefficient whereas BJT has positive temperature coefficient |
| Answer» B. Both MOSFET and BJT have positive temperature coefficient | |
| 183. |
Compared to Power MOSFET, the Power BJT has |
| A. | Lower switching losses but higher conduction loss |
| B. | . Higher switching losses and higher conduction loss |
| C. | Higher switching losses but lower conduction loss |
| D. | Lower switching losses and lower conduction loss |
| Answer» D. Lower switching losses and lower conduction loss | |
| 184. |
The three terminals of MCT |
| A. | Anode, cathode, gate |
| B. | Collector, emitter, gate |
| C. | Drain, source, base |
| D. | Drain, source, gate |
| Answer» B. Collector, emitter, gate | |
| 185. |
The three terminals of IGBT |
| A. | Collector, emitter, base |
| B. | Drain, source, base |
| C. | Drain, source, gate |
| D. | Collector, emitter, gate |
| Answer» E. | |
| 186. |
The three terminals of power MOSFET |
| A. | Collector, Emitter, base |
| B. | Drain, source, base |
| C. | Drain, source, gate |
| D. | Collector, emitter, gate |
| Answer» D. Collector, emitter, gate | |
| 187. |
Reverse recovery current in a diode depends on |
| A. | Forward field current |
| B. | Storage charge |
| C. | Temperature |
| D. | PIV |
| Answer» B. Storage charge | |
| 188. |
The softness factor for soft-recovery and fast-recovery diodes are respectively |
| A. | 1, >1 |
| B. | <1, 1 |
| C. | 1, 1 |
| D. | 1, <1 |
| Answer» E. | |
| 189. |
The cut-in voltage and forward-voltage drop of the diode are respectively |
| A. | 0.7V, 0.7V |
| B. | 0.7V, 1V |
| C. | 0.7V, 0.6V |
| D. | 1V, 0.7V |
| Answer» D. 1V, 0.7V | |
| 190. |
The transformer utilization factor of a half wave rectifier is approximately |
| A. | 0.6 |
| B. | 0.3 |
| C. | 0.9 |
| D. | . 1.1 |
| Answer» C. 0.9 | |
| 191. |
In an intrinsic semiconductor, the Fermi-level is |
| A. | closer to the valence band |
| B. | midway between conduction and valence band |
| C. | closer to the conduction band |
| D. | within the valence band |
| Answer» D. within the valence band | |
| 192. |
The value of ripple factor of a half wave rectifier without filter is approximately |
| A. | 1.2 |
| B. | o.2 |
| C. | . 2.2 |
| D. | 2.0 |
| Answer» B. o.2 | |
| 193. |
In a JFET, at pinch-off voltage applied on the gate |
| A. | The drain current becomes almost zero |
| B. | The drain current begins to decrease |
| C. | The drain current is almost at saturation value |
| D. | The drain to source voltage is close to zero volts |
| Answer» D. The drain to source voltage is close to zero volts | |
| 194. |
Space charge region around a P-N junction |
| A. | does not contain mobile carries |
| B. | contains both free electrons and holes |
| C. | contains one type of mobile carriers depending on the level of doping of the P or N regions |
| D. | contains electrons only as free carriers |
| Answer» B. contains both free electrons and holes | |
| 195. |
In a full wave rectifier without filter, the ripple factor is |
| A. | 0.482 |
| B. | 1.21 |
| C. | 1.79 |
| D. | 2.05 |
| Answer» B. 1.21 | |
| 196. |
The breakdown mechanism in a lightly doped p-n junction under reverse biased condition is called |
| A. | avalanche breakdown |
| B. | zener breakdown |
| C. | breakdown by tunnelling |
| D. | high voltage breakdown |
| Answer» B. zener breakdown | |
| 197. |
Which of the following is a half controlled semiconductor device? |
| A. | MOSFET |
| B. | GTO |
| C. | MCT |
| D. | SCR |
| Answer» E. | |
| 198. |
Which of the following is called as uncontrolled semiconductor device? |
| A. | Diode |
| B. | Thyristor |
| C. | GTO |
| D. | MOSFET |
| Answer» B. Thyristor | |
| 199. |
The MOSFET has (i)Higher Power handling capability than BJT (ii) Faster switching speed than BJT (iii) High on state resistance (iv) Secondary breakdown voltage problem which of the above statements are incorrect? |
| A. | (i), (iii), (iv) |
| B. | (ii), (iii) |
| C. | All of the above |
| D. | (ii), (iii), (iv) |
| Answer» B. (ii), (iii) | |
| 200. |
Which of the following is true about the diodes A. During forward biased small amount of voltage drop will appear across anode and cathode B. If the reverse voltage exceed VRRM the diode will destroy C. trr is depends on softness factor D. schottky diodes have low trr |
| A. | All are true |
| B. | A, B, D |
| C. | A, B,C |
| D. | B,C, D |
| Answer» D. B,C, D | |