DBATU Model MCQ – Power Electronics Views: 183 [adinserter block="1"] Welcome to your Power Electronics, dated April 19, 2024 1. The typical ratio of latching current to holding current in a 20A thyristor isDeselect Answer 5.0 2.0 1.0 0.5 2. Circuit turn-off time of an SCR is defined as the timeDeselect Answer taken by the SCR to turn off required for SCR current to become zero for which the SCR is reverse biased by the commutation circuit for which the SCR is reverse biased to reduce its current below the holding current 3. 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?Deselect Answer (i), (iii), (iv) (ii), (iii) (ii), (iii), (iv) All of the above 4. A single phase full - wave half controlled bridge converter feeds an inductive loaD. The two SCRs in the converter are connected to a common DC bus. The converter has to have a free wheeling diodeDeselect Answer because the converter inherently does not provide for free wheeling Because the converter does not provide for freewheeling for high values of triggering angles Or else the freewheeling action of the converter will cause shorting of the AC supply Or else if a gate pulse to one of the SCRs is missed, it will subsequently cause a high load current in the other SCR 5. The average output voltage(Vdc) of the full wave diode bridge rectifier isDeselect Answer Vm/2 3Vm/pi 2Vm/pi 4Vm/pi 6. The typical ratio of latching current to holding current in a 20A thyristor isDeselect Answer 5.0 2.0 1.0 0.5 7. The main disadvantage of voltage doubler power supply circuit isDeselect Answer Excessive current Excessive voltage Insufficient rectification Poor regulation under heavy loads 8. The output of a rectifier circuit without filter isA.Deselect Answer 50 Hz AC smooth DC pulsating DC 60 hz AC 9. For a JFET, when VDS is increased beyond the pinch off voltage, the drain currentDeselect Answer Remains constant Decreases Increases First decreases and then increases 10. Compared to Power MOSFET, the Power BJT hasDeselect Answer Lower switching losses but higher conduction loss Higher switching losses and higher conduction loss Higher switching losses but lower conduction loss Lower switching losses and lower conduction loss Please fill in the comment box below. [adinserter block="1"]
