27 Power Electronics questions from the Electrical Core bank, written for Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd.
Free to start: the 2-minute EE readiness check — six questions and a result.
A.delay between the instant a thyristor becomes forward biased and the gate pulse, which controls the average output voltage of a converter
B.deliberate delay between turning off one switch of an inverter leg and turning on its complement to avoid shoot-through, at the cost of output distortion
C.four-layer PNPN device turned on by a gate pulse and turned off only when anode current falls below the holding current
D.comparison of a sine reference with a high-frequency triangular carrier, where modulation index sets the fundamental output voltage
Answer + AI explanation with Pro
2. Which term means: "four-layer PNPN device turned on by a gate pulse and turned off only when anode current falls below the holding current"?
Junior
A.Thyristor (SCR)
B.Freewheeling diode
C.Boost chopper
D.Dead time
Answer + AI explanation with Pro
3. Which statement is correct?
Junior
A.Thyristor (SCR) — comparison of a sine reference with a high-frequency triangular carrier, where modulation index sets the fundamental output voltage
B.Thyristor (SCR) — step-up DC-DC converter with output voltage Vin/(1−D), so the output rises steeply as the duty ratio approaches one
C.Thyristor (SCR) — four-layer PNPN device turned on by a gate pulse and turned off only when anode current falls below the holding current
D.Thyristor (SCR) — step-down DC-DC converter whose average output voltage equals duty ratio times input voltage in continuous conduction
Answer + AI explanation with Pro
4. What is Firing angle?
Junior
A.delay between the instant a thyristor becomes forward biased and the gate pulse, which controls the average output voltage of a converter
B.voltage-controlled switch combining MOSFET gate drive with BJT conduction, dominant from a few kW to MW at switching frequencies up to about 20 kHz
C.diode across an inductive load that carries load current when the switch turns off, preventing negative output voltage and improving power factor
D.comparison of a sine reference with a high-frequency triangular carrier, where modulation index sets the fundamental output voltage
Answer + AI explanation with Pro
5. Which term means: "delay between the instant a thyristor becomes forward biased and the gate pulse, which controls the average output voltage of a converter"?
Junior
A.Dead time
B.Space vector modulation
C.Boost chopper
D.Firing angle
Answer + AI explanation with Pro
6. Which statement is correct?
Junior
A.Firing angle — delay between the instant a thyristor becomes forward biased and the gate pulse, which controls the average output voltage of a converter
B.Firing angle — inverter PWM treating the three legs as one rotating vector, giving about 15% higher DC bus utilisation than sine-triangle PWM
C.Firing angle — four-layer PNPN device turned on by a gate pulse and turned off only when anode current falls below the holding current
D.Firing angle — diode across an inductive load that carries load current when the switch turns off, preventing negative output voltage and improving power factor
Answer + AI explanation with Pro
7. What is Buck chopper?
Junior
A.delay between the instant a thyristor becomes forward biased and the gate pulse, which controls the average output voltage of a converter
B.four-layer PNPN device turned on by a gate pulse and turned off only when anode current falls below the holding current
C.step-down DC-DC converter whose average output voltage equals duty ratio times input voltage in continuous conduction
D.comparison of a sine reference with a high-frequency triangular carrier, where modulation index sets the fundamental output voltage
Answer + AI explanation with Pro
8. Which term means: "step-down DC-DC converter whose average output voltage equals duty ratio times input voltage in continuous conduction"?
Junior
A.Boost chopper
B.Buck chopper
C.Freewheeling diode
D.Sinusoidal PWM
Answer + AI explanation with Pro
9. Which statement is correct?
Junior
A.Buck chopper — comparison of a sine reference with a high-frequency triangular carrier, where modulation index sets the fundamental output voltage
B.Buck chopper — voltage-controlled switch combining MOSFET gate drive with BJT conduction, dominant from a few kW to MW at switching frequencies up to about 20 kHz
C.Buck chopper — step-down DC-DC converter whose average output voltage equals duty ratio times input voltage in continuous conduction
D.Buck chopper — step-up DC-DC converter with output voltage Vin/(1−D), so the output rises steeply as the duty ratio approaches one
Answer + AI explanation with Pro
10. What is Boost chopper?
Junior
A.comparison of a sine reference with a high-frequency triangular carrier, where modulation index sets the fundamental output voltage
B.four-layer PNPN device turned on by a gate pulse and turned off only when anode current falls below the holding current
C.step-down DC-DC converter whose average output voltage equals duty ratio times input voltage in continuous conduction
D.step-up DC-DC converter with output voltage Vin/(1−D), so the output rises steeply as the duty ratio approaches one
Answer + AI explanation with Pro
11. Which term means: "step-up DC-DC converter with output voltage Vin/(1−D), so the output rises steeply as the duty ratio approaches one"?
Junior
A.Boost chopper
B.Sinusoidal PWM
C.IGBT
D.Dead time
Answer + AI explanation with Pro
12. Which statement is correct?
Junior
A.Boost chopper — step-up DC-DC converter with output voltage Vin/(1−D), so the output rises steeply as the duty ratio approaches one
B.Boost chopper — four-layer PNPN device turned on by a gate pulse and turned off only when anode current falls below the holding current
C.Boost chopper — step-down DC-DC converter whose average output voltage equals duty ratio times input voltage in continuous conduction
D.Boost chopper — deliberate delay between turning off one switch of an inverter leg and turning on its complement to avoid shoot-through, at the cost of output distortion
Answer + AI explanation with Pro
13. What is Freewheeling diode?
Mid
A.four-layer PNPN device turned on by a gate pulse and turned off only when anode current falls below the holding current
B.deliberate delay between turning off one switch of an inverter leg and turning on its complement to avoid shoot-through, at the cost of output distortion
C.diode across an inductive load that carries load current when the switch turns off, preventing negative output voltage and improving power factor
D.step-down DC-DC converter whose average output voltage equals duty ratio times input voltage in continuous conduction
Answer + AI explanation with Pro
14. Which term means: "diode across an inductive load that carries load current when the switch turns off, preventing negative output voltage and improving power factor"?
Mid
A.Freewheeling diode
B.Thyristor (SCR)
C.Buck chopper
D.Dead time
Answer + AI explanation with Pro
15. Which statement is correct?
Mid
A.Freewheeling diode — voltage-controlled switch combining MOSFET gate drive with BJT conduction, dominant from a few kW to MW at switching frequencies up to about 20 kHz
B.Freewheeling diode — four-layer PNPN device turned on by a gate pulse and turned off only when anode current falls below the holding current
C.Freewheeling diode — comparison of a sine reference with a high-frequency triangular carrier, where modulation index sets the fundamental output voltage
D.Freewheeling diode — diode across an inductive load that carries load current when the switch turns off, preventing negative output voltage and improving power factor
Answer + AI explanation with Pro
16. What is Sinusoidal PWM?
Mid
A.step-down DC-DC converter whose average output voltage equals duty ratio times input voltage in continuous conduction
B.comparison of a sine reference with a high-frequency triangular carrier, where modulation index sets the fundamental output voltage
C.four-layer PNPN device turned on by a gate pulse and turned off only when anode current falls below the holding current
D.step-up DC-DC converter with output voltage Vin/(1−D), so the output rises steeply as the duty ratio approaches one
Answer + AI explanation with Pro
17. Which term means: "comparison of a sine reference with a high-frequency triangular carrier, where modulation index sets the fundamental output voltage"?
Mid
A.Firing angle
B.Sinusoidal PWM
C.Space vector modulation
D.Buck chopper
Answer + AI explanation with Pro
18. Which statement is correct?
Mid
A.Sinusoidal PWM — comparison of a sine reference with a high-frequency triangular carrier, where modulation index sets the fundamental output voltage
B.Sinusoidal PWM — four-layer PNPN device turned on by a gate pulse and turned off only when anode current falls below the holding current
C.Sinusoidal PWM — diode across an inductive load that carries load current when the switch turns off, preventing negative output voltage and improving power factor
D.Sinusoidal PWM — deliberate delay between turning off one switch of an inverter leg and turning on its complement to avoid shoot-through, at the cost of output distortion
Answer + AI explanation with Pro
19. What is IGBT?
Mid
A.comparison of a sine reference with a high-frequency triangular carrier, where modulation index sets the fundamental output voltage
B.voltage-controlled switch combining MOSFET gate drive with BJT conduction, dominant from a few kW to MW at switching frequencies up to about 20 kHz
C.step-down DC-DC converter whose average output voltage equals duty ratio times input voltage in continuous conduction
D.deliberate delay between turning off one switch of an inverter leg and turning on its complement to avoid shoot-through, at the cost of output distortion
Answer + AI explanation with Pro
20. Which term means: "voltage-controlled switch combining MOSFET gate drive with BJT conduction, dominant from a few kW to MW at switching frequencies up to about 20 kHz"?
Mid
A.Space vector modulation
B.Firing angle
C.Freewheeling diode
D.IGBT
Answer + AI explanation with Pro
21. Which statement is correct?
Mid
A.IGBT — delay between the instant a thyristor becomes forward biased and the gate pulse, which controls the average output voltage of a converter
B.IGBT — step-up DC-DC converter with output voltage Vin/(1−D), so the output rises steeply as the duty ratio approaches one
C.IGBT — voltage-controlled switch combining MOSFET gate drive with BJT conduction, dominant from a few kW to MW at switching frequencies up to about 20 kHz
D.IGBT — diode across an inductive load that carries load current when the switch turns off, preventing negative output voltage and improving power factor
Answer + AI explanation with Pro
22. What is Dead time?
Senior
A.step-up DC-DC converter with output voltage Vin/(1−D), so the output rises steeply as the duty ratio approaches one
B.deliberate delay between turning off one switch of an inverter leg and turning on its complement to avoid shoot-through, at the cost of output distortion
C.delay between the instant a thyristor becomes forward biased and the gate pulse, which controls the average output voltage of a converter
D.voltage-controlled switch combining MOSFET gate drive with BJT conduction, dominant from a few kW to MW at switching frequencies up to about 20 kHz
Answer + AI explanation with Pro
23. Which term means: "deliberate delay between turning off one switch of an inverter leg and turning on its complement to avoid shoot-through, at the cost of output distortion"?
Senior
A.Thyristor (SCR)
B.Dead time
C.IGBT
D.Boost chopper
Answer + AI explanation with Pro
24. Which statement is correct?
Senior
A.Dead time — deliberate delay between turning off one switch of an inverter leg and turning on its complement to avoid shoot-through, at the cost of output distortion
B.Dead time — inverter PWM treating the three legs as one rotating vector, giving about 15% higher DC bus utilisation than sine-triangle PWM
C.Dead time — four-layer PNPN device turned on by a gate pulse and turned off only when anode current falls below the holding current
D.Dead time — diode across an inductive load that carries load current when the switch turns off, preventing negative output voltage and improving power factor
Answer + AI explanation with Pro
25. What is Space vector modulation?
Senior
A.voltage-controlled switch combining MOSFET gate drive with BJT conduction, dominant from a few kW to MW at switching frequencies up to about 20 kHz
B.comparison of a sine reference with a high-frequency triangular carrier, where modulation index sets the fundamental output voltage
C.deliberate delay between turning off one switch of an inverter leg and turning on its complement to avoid shoot-through, at the cost of output distortion
D.inverter PWM treating the three legs as one rotating vector, giving about 15% higher DC bus utilisation than sine-triangle PWM
Answer + AI explanation with Pro
26. Which term means: "inverter PWM treating the three legs as one rotating vector, giving about 15% higher DC bus utilisation than sine-triangle PWM"?
Senior
A.Buck chopper
B.Space vector modulation
C.IGBT
D.Firing angle
Answer + AI explanation with Pro
27. Which statement is correct?
Senior
A.Space vector modulation — inverter PWM treating the three legs as one rotating vector, giving about 15% higher DC bus utilisation than sine-triangle PWM
B.Space vector modulation — step-up DC-DC converter with output voltage Vin/(1−D), so the output rises steeply as the duty ratio approaches one
C.Space vector modulation — diode across an inductive load that carries load current when the switch turns off, preventing negative output voltage and improving power factor
D.Space vector modulation — voltage-controlled switch combining MOSFET gate drive with BJT conduction, dominant from a few kW to MW at switching frequencies up to about 20 kHz
Answer + AI explanation with Pro
Free to start
Start with a free readiness check
Sign up free for the 2-minute EE readiness check and a scored result. Answers, explanations and the AI tutor on every Power Electronics question come with Pro.