Questions

Multiple-choice questions you can practise one by one. Open a question, tap an answer and see at once whether it is right. For a random set, try Quick practice.

941 questions

• An ideal boost chopper operates from 100 V with duty cycle 0.5. Using Vout = Vin/(1-D), what is the ideal output voltage?

  Industrial Electronics & Control of Drives › Unit 3: Inverters, Choppers, Dual Converters and Cyclo-Convertors · Hard

• A DC chopper has an ideal input of 200 V and a duty cycle of 0.35 in buck operation. What is its ideal average output voltage?

  Industrial Electronics & Control of Drives › Unit 3: Inverters, Choppers, Dual Converters and Cyclo-Convertors · Hard

• A TRIAC-based AC controller produces asymmetric half-cycle conduction because of its triggering circuit. What is a likely supply-side concern?

  Industrial Electronics & Control of Drives › Unit 1: Introduction to Thyristors · Hard

• A UJT relaxation oscillator is used to generate firing pulses. If its timing capacitor value is increased with other parameters unchanged, what generally happens?

  Industrial Electronics & Control of Drives › Unit 1: Introduction to Thyristors · Hard

• A freewheeling diode is added across an inductive DC load supplied by a controlled rectifier. Which effect is expected during the freewheeling interval?

  Industrial Electronics & Control of Drives › Unit 2: Controlled Rectifiers · Hard

• A three-phase fully controlled bridge has a firing-angle control fault affecting one valve pulse. What is a likely consequence?

  Industrial Electronics & Control of Drives › Unit 2: Controlled Rectifiers · Hard

• In a line-commutated fully controlled converter, under ideal continuous-current conditions, the average DC voltage becomes negative when the firing angle is:

  Industrial Electronics & Control of Drives › Unit 2: Controlled Rectifiers · Hard

• A single-phase fully controlled bridge operates with a sufficiently large continuous DC current. What does increasing firing angle generally do in rectifier operation below the in…

  Industrial Electronics & Control of Drives › Unit 2: Controlled Rectifiers · Hard

• A controlled rectifier supplies a highly inductive load. Why may the output current be smoother than the output voltage?

  Industrial Electronics & Control of Drives › Unit 2: Controlled Rectifiers · Hard

• A power SCR overheats even though its average current is within rating. Which additional check is especially relevant?

  Industrial Electronics & Control of Drives › Unit 1: Introduction to Thyristors · Hard

• An SCR in a high-voltage circuit turns on without a gate pulse when voltage rises very rapidly. Which protection is most directly relevant?

  Industrial Electronics & Control of Drives › Unit 1: Introduction to Thyristors · Hard

• A thyristor is triggered but the anode current never reaches its latching current. What is the likely outcome after the gate pulse is removed?

  Industrial Electronics & Control of Drives › Unit 1: Introduction to Thyristors · Hard

• An ideal single-phase half-wave controlled rectifier feeds a resistive load from a sinusoidal source. If the firing angle is increased while the supply remains unchanged, what hap…

  Industrial Electronics & Control of Drives › Unit 2: Controlled Rectifiers · Hard

• Which method is commonly used to control the output of a phase-controlled rectifier?

  Industrial Electronics & Control of Drives › Unit 2: Controlled Rectifiers · Medium

• Why should SCR di/dt be limited during turn-on?

  Industrial Electronics & Control of Drives › Unit 1: Introduction to Thyristors · Medium

• What does the term overlap angle refer to in a line-commutated converter?

  Industrial Electronics & Control of Drives › Unit 2: Controlled Rectifiers · Medium

• Which issue is commonly associated with phase-controlled rectifiers?

  Industrial Electronics & Control of Drives › Unit 2: Controlled Rectifiers · Medium

• Why are cycloconverters often associated with low-speed, high-power drives?

  Industrial Electronics & Control of Drives › Unit 3: Inverters, Choppers, Dual Converters and Cyclo-Convertors · Medium

• What is the main function of a cycloconverter?

  Industrial Electronics & Control of Drives › Unit 3: Inverters, Choppers, Dual Converters and Cyclo-Convertors · Medium

• Why may circulating current flow in a dual converter?

  Industrial Electronics & Control of Drives › Unit 3: Inverters, Choppers, Dual Converters and Cyclo-Convertors · Medium